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Focus adjustment information forming device |
| RE36280 |
Focus adjustment information forming device
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| Patent Drawings: | |
| Inventor: |
Kawabata, et al. |
| Date Issued: |
August 24, 1999 |
| Application: |
08/057,113 |
| Filed: |
May 4, 1993 |
| Inventors: |
Ichida; Yasuteru (Tokyo, JP)
Kawabata; Takashi (Kanagawa, JP)
Masuda; Hidetoshi (Kanagawa, JP)
Miyanari; Hiroshi (Kanagawa, JP)
Nishimori; Eiji (Tokyo, JP)
Odaka; Yukio (Kanagawa, JP)
Shingu; Toshiaki (Kanagawa, JP)
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| Assignee: |
Canon Kabushiki Kaisha (Tokyo, JP) |
| Primary Examiner: |
Adams; Russell |
| Assistant Examiner: |
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| Attorney Or Agent: |
Robin, Blecker & Daley |
| U.S. Class: |
396/122; 396/49; 706/900 |
| Field Of Search: |
354/400; 354/402; 354/403; 354/404; 354/405; 354/406; 354/407; 354/408; 354/432; 396/49; 396/122 |
| International Class: |
G02B 7/28 |
| U.S Patent Documents: |
4339185; 4364650; 4394078; 4395099; 4445778; 4476383; 4534636; 4621917; 4664495; 4720724; 4740806; 4745427; 4800409; 4827303; 4908646; 4912495; 4943824; 4951082; 4977423; 5051766; 5070352; 5313245 |
| Foreign Patent Documents: |
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| Other References: |
Fuzzy Set Theory and Its Applications, H.J. Zimmermann, Kluwer Academic Publishers, 1985, pp. 11-14.. |
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| Abstract: |
Disclosed is a focus adjustment information forming device of the kind arranged to measure distances at a plurality of distance measuring areas on a picture plane specified by optical means which has its focal point being adjusted and to form information on adjustment of the focal point, the plurality of distance measuring areas including a center distance area located approximately in the center of the picture plane. The device comprises first priority means for giving priority to a measured distance value which represents the nearest distance among measured distance values obtained from the distance measuring areas; a second priority means for giving priority to the measured distance value obtained from the center distance measuring area according to its relations to the measured distance values of other distance measuring areas when one of the measured distance values of the distance measuring areas other than the center distance measuring area represents the nearest distance; and focus adjustment information forming means for forming information on adjustment of the focal point of the optical means on the basis of outputs of the first and second priority means. |
| Claim: |
What is claimed is:
1. A focus adjustment information forming device, comprising:
(a) detection means for detecting signals depending on distances to objects existing in a plurality of directions relative to a photographic scene, and
(b) a focus adjustment information forming means for forming a focus adjustment information centering on an object existing in a central target direction in response to said detection means when the distances to the objects in said plurality ofdirections are in mutual relations of a long distance in a marginal target direction toward one marginal portion of said photographic scene, an intermediate distance in said central target direction toward a central portion of said photographic scene anda short distance in another marginal target direction toward another marginal portion of said photographic scene.
2. A device according to claim 1, wherein said focus adjustment information forming means includes means for forming a focus adjustment information centering on the object existing in said another marginal target direction when the distances ofthe objects existing in the plurality of distances are not in said mutual relation of the long distance in the one marginal target direction, the intermediate distance in the central target direction and the short distance in the another marginal targetdirection and are in a mutual relation wherein the distance in the one marginal target direction is shorter than the distances in the central target direction and the another marginal target direction.
3. A device according to claim 2, wherein said focus adjustment information forming means includes means for forming a focus adjustment information centering on the object existing in the central target direction when the distances of theobjects existing in the plurality of directions are not in the mutual relation wherein the distance in the one marginal target direction is long, the distance in the central target direction is intermediate, and the distance in the another marginaltarget direction is short, and are not in a mutual relation wherein the distance in the one marginal target direction is shorter than the distances in the central and the another marginal target directions.
4. A device according to claim 1, wherein said focus adjustment information forming means includes means for forming a focus adjustment information centering on the object existing in the central target direction when the distances of theobjects existing in the plurality of directions are not in the mutual relation wherein the distance in the one marginal target direction is long, the distance in the central target direction is intermediate, and the distance in the another marginaltarget direction is short, and are in a mutual relation wherein the distance in the another marginal target direction is shorter than the distances in the central target direction and in the one marginal target direction.
5. A device according to claim 4, wherein said focus adjustment information forming means includes means for forming a focus adjustment information centering on the object existing in the central target direction when the distances of theobjects existing in the plurality of directions are not in the mutual relation wherein the distance in the one marginal target direction is long, the distance in the central target direction is intermediate, and the distance in the another marginaltarget direction is short, and are not in a mutual relation wherein the distance in the another marginal target direction is shorter than the distances in the central target direction and in the one marginal target direction.
6. A device according to claim 1, wherein said focus adjustment information forming means includes a program operation circuit.
7. A device according to claim 1, wherein said focus adjustment information forming means includes an analog operation circuit.
8. A device according to claim 1, wherein said focus adjustment information forming means includes means for judging said long distance, said intermediate distance and said short distance on the basis of their absolute distances.
9. A device according to claim 1, wherein said focus adjustment information forming means includes means for judging said long distance, said intermediate distance and said short distance on the basis of their relative distances.
10. A device according to claim 1, wherein said focus adjustment information forming means includes means for judging said long distance, said intermediate distance and said short distance in view of a depth of field. .Iadd.
11. A camera comprising:
measuring means for outputting information associated with an object to be photographed;
a fuzzy computer for receiving an output from the measuring means as an input value, obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and the then-partmembership function, both of which correspond to a plurality of rules representing a degree of influence of the input value on an optimal exposure, obtaining a center of gravity value from a plurality of fitting degree corresponding to the rules, andobtaining a determination value as a result of inference; and
means for determining photographic conditions from the determination value from the fuzzy computer and the output from said measuring means..Iaddend..Iadd.12. A camera according to claim 11, wherein said measuring means includes photometricmeans for outputting a plurality of object brightness signals including a signal representing a brightness level of at least a central portion of the object..Iaddend..Iadd.13. A camera according to claim 12, wherein said measuring means further includesdistance measuring means for outputting distance data of the object..Iaddend..Iadd.14. A camera according to claim 11, wherein the photographic conditions include an exposure value and data representing a light emission enable/disable state of anelectronic flash..Iaddend..Iadd.15. An exposure value operation apparatus for a camera, comprising:
photometric means for outputting a plurality of object brightness signals including a signal representing a brightness level of at least a central portion of an object;
a fuzzy computer for receiving an output from said photometric means as an input value, obtaining a fitting degree of the input value with respect to a then-part membership function from an if-part membership function and the then-part membershipfunction, both of which correspond to a plurality of rules representing a degree of influence of the input value on an exposure state, obtaining a center of gravity value from a plurality of fitting degrees corresponding to the rules, and obtaining adetermination value as an inference result; and
operating means for determining weighting of the brightness signal from said photometric means to obtain an exposure value in accordance with the
determination value from said fuzzy computer..Iaddend..Iadd.16. An exposure value operation apparatus for a camera, comprising:
photometric means for outputting a plurality of object brightness signals including a signal representing a brightness level of at least a central portion of an object;
distance measuring means for outputting distance data of the object;
a fuzzy computer for receiving outputs from said distance measuring means and said photometric means as input values, obtaining a fitting degree of the input values with respect to a then-part membership function from an if-part membershipfunction and the then-part membership function, both of which correspond to a plurality of rules representing a degree of influence of the input values on an exposure state, obtaining a center of gravity value from a plurality of fitting degreescorresponding to the rules, and obtaining a determination value as an inference result; and
operating means for determining weighting of the brightness signal from said photometric means to obtain the exposure value in accordance with the determination value from said fuzzy computer..Iaddend..Iadd.17. An electronic flash controlapparatus for a camera, comprising:
photometric means for outputting a plurality of object brightness signals including a signal representing a brightness level of at least a central portion of an object;
a fuzzy computer for receiving an output from said photometric means as an input value, obtaining a fitting degree of the input value with respect to a then-part membership function from an if-part membership function and the then-part membershipfunction, both of which correspond to a plurality of rules representing a degree of influence of the input value on electronic flash control, obtaining a center of gravity value from a plurality of fitting degrees corresponding to the rules, andobtaining a determination value as an inference result; and
electronic flash control means for controlling a light emission enable/disable state of an electronic flash by the determination value from said fuzzy computer..Iaddend..Iadd.18. An exposure determining apparatus for a camera having means formeasuring a brightness distribution of an object, comprising:
a fuzzy computer for obtaining fitness degrees against exposure conditions represented as a plurality of membership functions in accordance with input values corresponding to brightness distribution states of an object and outputting as adetermination value an inference result determined by operations for obtaining a center of gravity value from said plurality of fitness degrees;
control means for determining an exposing condition on the basis of the determination value; and
a control target object driven by an output from said control means..Iaddend..Iadd.19. An apparatus according to claim 18, wherein said control means includes at least one of an exposure value operation circuit, an electronic flash lightemission enable/disable control circuit, and an electronic flash light emission angle control circuit..Iaddend..Iadd.20. An apparatus according to claim 18, wherein the target object includes at least one of a shutter, an aperture, and an electronicflash..Iaddend..Iadd.21. A camera comprising:
measuring means for outputting information associated with an object to be photographed;
a fuzzy operation circuit for receiving an output from the measuring means as an input value, obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and thethen-part membership function, both of which correspond to a plurality of rules representing a degree of influence of the input value on an optimal exposure;
a defuzzifier operation circuit for obtaining a determination value as a result of inference in correspondence with a center of gravity value obtained from said fitting degree; and
means for determining photographic conditions from the determination value from the defuzzifier operation circuit and the output from the measuring means..Iaddend..Iadd.22. A camera according to claim 21, wherein the if-part membership functionis a function in which an axis of abscissa corresponds to the output from the measuring means and an axis of ordinate corresponds to the degree of influence from 0 to 1, and the then-part membership function is a function in which the axis of abscissacorresponds to a correction value, and the axis of ordinate corresponds to the degree of influence from 0 to 1..Iaddend..Iadd.23. An exposure value operation apparatus for a camera, comprising:
photometric means for outputting a plurality of object brightness signals including a signal representing a brightness level of at least a central portion of an object;
a fuzzy operation circuit for receiving an output from the photometric means as an input value, obtaining a fitting degree of the input value with respect to a then-part membership function from an in-part membership function and the then-partmembership function, both of which correspond to a plurality of rules representing a degree of influence of the input value on an exposure state;
a defuzzifier operation circuit for obtaining a center of gravity value form a plurality of fitting degrees corresponding to the rules, and obtaining a determination value as an inference result; and
operating means for determining weighting of the brightness signal from said photometric means to obtain an exposure value in accordance with the determination value from the defuzzifier operation circuit..Iaddend..Iadd.24. An exposure valueoperation apparatus for a camera, comprising:
photometric means for outputting a plurality of object brightness level of at least a central portion of an object;
distance measuring means for outputting distance data of the object;
a fuzzy operation circuit for receiving an output from the distance measuring means and the photometric means as input values, obtaining a fitting degree of the input values with respect to as then-part membership function from an if-partmembership function and the then-part membership function, both of which correspond to a plurality of rules representing a degree of influence of the input values on an exposure state;
a defuzzifier operation circuit for obtaining a center of gravity value in correspondence with an output from the fuzzy operation circuit, and obtaining a determination value as an inference result; and
operating means for determining weighting of the brightness signal from said photometric means to obtain an exposure value in accordance with the determination value from the defuzzifier operation circuit..Iaddend..Iadd.25. An exposure valueoperation apparatus for a camera, comprising:
photometric means for outputting a plurality of object brightness signals including a signal representing a brightness level of at least a central portion of an object;
a fuzzy operation circuit for receiving an output from the photometric means as an input value, obtaining a fitting degree of the input value with respect to a then-part membership function from an if-part membership function and the then-partmembership function, both of which correspond to a plurality of rules representing a degree of influence of the input value on electronic flash control;
a defuzzifier operation circuit for obtaining a center of gravity value from a plurality of fitting degrees corresponding to the rules, and obtaining a determination value as an inference result; and
electronic flash control means for controlling a light emission enable/disable state of an electronic flash by the determination value from the defuzzifier operation circuit..Iaddend..Iadd.26. A method for determining photographic conditions tobe used in controlling a camera, comprising the steps of:
providing information associated with an object to be photographed;
receiving said information as an input value to a fuzzy operation circuit, obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and the then-partmembership function, both of which correspond to a plurality of rules representing a degree of influence of the input value on an optimal exposure;
obtaining with a defuzzifier operation circuit a center of gravity value as a result of inference in correspondence with an output from the fuzzy operation circuit; and
determining photographic conditions from the determination value from the defuzzifier operation circuit and said information..Iaddend..Iadd.27. A camera according to claim 26, wherein the if-part membership function is a function in which anaxis of abscissa corresponds to the output from the measuring means and an axis of ordinate corresponds to the degree of influence from 0 to 1, and the then-part membership function is a function in which the axis of abscissa corresponds to a correctionvalue, and the axis of ordinate corresponds to the degree of influence from 0 to 1..Iaddend..Iadd.28. An exposure value operation method for a camera, comprising the step of:
outputting with a photometric means a plurality of object brightness signals including a signal representing a brightness level of at least a central portion of an object;
receiving an output from the photometric means as an input value to a fuzzy operation circuit, obtaining a fitting degree of the input value with respect to a then-part membership function from an if-part membership function and the then-partmembership function, both of which correspond to a plurality of rules representing a degree of influence of the input value on an exposure state;
obtaining with a defuzzifier operation circuit a center of gravity value from a plurality of fitting degrees corresponding to the rules, and obtaining a determination value as an inference result; and
determining weighting of the brightness signal from the photometric means to obtain an exposure value in accordance with the determination value from the defuzzifier operation circuit..Iaddend..Iadd.29. An exposure value operation method for acamera, comprising the steps of:
outputting with photometric means a plurality of object brightness levels of at least a central portion of an object;
outputting with distance measuring means distance data of the object;
receiving outputs from the distance measuring means and the photometric means as input values to a fuzzy operation circuit, obtaining a fitting degree of the input values with respect to a then-part membership function from an if-part membershipfunction and the then-part membership function, both of which correspond to a plurality of rules representing a degree of influence of the input values on an exposure state;
obtaining with a defuzzifier operation circuit a center of gravity value in correspondence with an output from the fuzzy operation circuit, and obtaining a determination value as an inference result; and
determining weighting of the brightness signal from the photometric means to obtain the exposure value in accordance with the determination value from the defuzzifier operation circuit..Iaddend..Iadd.30. An electronic flash control method for acamera, comprising the steps of:
outputting with a photometric means a plurality of object brightness signals including a signal representing a brightness level of at least a central portion of an object;
receiving an output form the photometric means as an input value to a fuzzy operation circuit, obtaining a fitting degree of the input value with respect to a then-part membership function from an if-part membership function and the then-partmembership function, both of which correspond to plurality of rules representing a degree of influence of the input value on electronic flash control;
obtaining with a defuzzifier operation circuit a center of gravity value from a plurality of fitting degrees corresponding to the rules, and obtaining a determination value as an inference result; and
controlling with an electronic flash control means a light emission enable/disable sate of an electronic flash by the determination value from the defuzzifier operation circuit..Iaddend..Iadd.31. A control device for an image handling apparatus,comprising:
generating means for generating information for said image handling apparatus;
operation means for receiving an output from said generating means as an input value, obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and thethen-part membership function, both of which correspond to a plurality of rules representing a degree of influence of the input value on an operation of said image handling apparatus, obtaining a center of gravity value from a plurality of fitting degreecorresponding to the rules, and obtaining a determination value as a result of inference; and
means for determining a condition associated with the operation of said image handling apparatus on the basis of the determination value..Iaddend..Iadd.32. A device according to claim 31, wherein said image handling apparatus includes acamera..Iaddend..Iadd.33. A device according to claim 31, wherein said generating means includes means for generating data on an object distance..Iaddend..Iadd.34. A device according to claims 31 or 33, wherein said generating means includesphotometric means for generating photometric data..Iaddend..Iadd.35. A device according to claim 34, wherein said photometric means includes means for generating a plurality of object brightness signals..Iaddend..Iadd.36. A device according to claim34, wherein said photometric means includes means for generating photometric data on an entire picture field..Iaddend..Iadd.37. A device according to claim 36, wherein said photometric means includes at least one of means for generating averagephotometric data on the entire picture field and means for generating partial photometric data on the entire picture field..Iaddend..Iadd.38. A device according to claim 31 or claim 33, wherein said generating means includes focal length means forgenerating focal length data..Iaddend..Iadd.39. A device according to claim 38, wherein said generating means includes means for generating diaphragm data..Iaddend..Iadd.40. A device according to claim 31 or claim 33, wherein said generating meansincludes at least one of means for generating diaphragm data and means for generating data on a remote-control device..Iaddend..Iadd.41. A device according to claim 31, wherein said operation means includes means for obtaining a value indicating alikely main object as the determination value..Iaddend..Iadd.42. A device according to claim 31, wherein said operation means includes means for obtaining a peak value..Iaddend..Iadd.43. A device according to claim 31, wherein said operation meansincludes means for obtaining an intermediate value..Iaddend..Iadd.44. An optical system, comprising:
generating means for generating information for said optical system;
operation means for receiving an output from said generating means as an input value, obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and thethen-part membership function, both of which correspond to a plurality of rules representing a degree of influence of the input value on an operation of said optical system, obtaining a center of gravity value from a plurality of fitting degreecorresponding to the rules, and obtaining a determination value as a result of the inference; and
means for determining a condition associated with the operation of said optical system on the basis of the determination value..Iaddend..Iadd.45. An optical system according to claim 44, wherein said optical system includes acamera..Iaddend..Iadd.46. A control device for an image handling apparatus, comprising:
generating means for generating information for said image handling apparatus;
operating means for receiving an output from said generating means as an input value, obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and thethen-part membership function, both of which correspond to a plurality of rules representing a degree of influence of the input value on an operation of said image handling apparatus, synthetically evaluating a plurality of fitting degree correspondingto the rules, and obtaining a determination value as a result of inference; and
means for determining a condition associated with the operation of said image handling apparatus on the basis of the determination value..Iaddend..Iadd.47. A device according to claim 46, wherein said image handling apparatus includes acamera..Iaddend..Iadd.48. A device according to claim 46, wherein said generating means includes means for generating data on an object distance..Iaddend..Iadd.49. A device according to claim 46, wherein said generating means includes photometric meansfor generating photometric data..Iaddend..Iadd.50. A device according to claim 49, wherein said photometric means includes means for generating a plurality of object brightness signals..Iaddend..Iadd.51. A device according to claim 50, wherein saidphotometric means includes at least one of means for generating photometric data on an entire picture field and means for generating partial photometric data on the entire picture field..Iaddend..Iadd.52. A device according to claim 46, wherein saidgenerating means includes means for generating focal length data..Iaddend..Iadd.53. A device according to claim 52, wherein said generating means includes means for generating diaphragm data..Iaddend..Iadd.54. A device according to claim 46, whereinsaid generating means includes at least one of means for generating diaphragm data and means for generating data on a remote-control device..Iaddend..Iadd.55. A device according to claim 46, wherein said operation means includes means for obtaining avalue indicating a likely main object as the determination value..Iaddend..Iadd.56. A device according to claim 46, wherein said operation means includes means for obtaining a peak value..Iaddend..Iadd.57. A device according to claim 46, wherein saidoperation means includes means for obtaining an intermediate value..Iaddend..Iadd.58. An optical system, comprising:
generating means for generating information for said optical system;
operation means for receiving an output from said generating means as an input value, obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and thethen-part membership function, both of which correspond to a plurality of rules representing a degree of influence of the input value on an operation of said optical system, synthetically evaluating a plurality of fitting degree corresponding to therules, and obtaining a determination value as a result of inference; and
means for determining a condition associated with the operation of said optical system on the basis of the determination value..Iaddend..Iadd.59. An optical system according to claim 58, wherein said optical system includes acamera..Iaddend..Iadd.60. A control device for an image handling apparatus, comprising:
generating means for generating information for said image handling apparatus;
operation means for receiving an output from said generating means as an input value, obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and thethen-part membership function, wherein the then-part membership function corresponds to a conversion rule obtaining from the input value two kinds of values converted in accordance with a degree of probable correctness and a value to weight the degree ofprobable correctness, and obtaining a degree of influence of the input value on an operation of said image handling apparatus by synthetically evaluating the two kinds of converted values; and
means for determining a condition associated with an operation of said image handling apparatus on the basis of the degree of
influence..Iaddend..Iadd.61. A device according to claim 60, wherein said image handling apparatus includes a camera..Iaddend..Iadd.62. A device according to claim 60, wherein said generating means includes means for generating data on anobject distance..Iaddend..Iadd.63. A device according to claim 60, wherein said generating means includes photometric means for generating photometric data..Iaddend..Iadd.64. A device according to claim 63, wherein said photometric means includes meansfor generating a plurality of object brightness signals..Iaddend..Iadd.65. A device according to claim 63, wherein said photometric means includes means for generating photometric data on an entire picture field..Iaddend..Iadd.66. A device according toclaim 65, wherein said photometric means includes at least one of means for generating average photometric data on the entire picture field and means for generating partial photometric data on the entire picture field..Iaddend..Iadd.67. A deviceaccording to claim 60 wherein said generating means includes means for generating focal length data..Iaddend..Iadd.68. A device according to claim 67, wherein said generating means includes means for generating diaphragm data..Iaddend..Iadd.69. Adevice according to claim 60, wherein said generating means includes at least one of means for generating diaphragm data and means for generating data on a remote-control device..Iaddend..Iadd.70. A device according to claim 60, wherein said operationmeans includes means for obtaining a value indicating a likely main object as the determination value..Iaddend..Iadd.71. A device according to claim 60, wherein said operation means includes means for obtaining a peak value..Iaddend..Iadd.72. A deviceaccording to claim 60, wherein said operation means includes means for obtaining an intermediate value..Iaddend..Iadd.73. An optical system, comprising:
generating means for generating information for said optical system;
operation means for receiving an output from said generating means as an input value, obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and thethen-part membership function, wherein the then-part membership function corresponds to a conversion rule obtaining from the input value two kinds of values converted in accordance with a degree of probable correctness and value to weight the degree ofprobable correctness and a value to weight the degree of probable correctness, and obtaining a degree of influence of the input value on an operation of said optical system by synthetically evaluating the two kinds of converted values; and
means for determining a condition associated with an operation of said optical system on the basis of the degree of influence..Iaddend..Iadd.74. An optical system according to claim 73, wherein said optical system includes acamera..Iaddend..Iadd.75. A control device for an image handling apparatus, comprising:
generating means for generating information for said image handling apparatus;
operation means for receiving an output from said generating means as an input value, obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and thethen-part membership function, both of which correspond to a plurality of rules representing a degree of influence of the input value on an operation of said image handling apparatus, obtaining a peak value from a plurality of fitting degreecorresponding to the rules, and obtaining a determination value as result of inference; and
means for determining a condition associated with the operation of said image handling apparatus on the basis of the determination value..Iaddend..Iadd.76. A device according to claim 75, wherein said image handling apparatus includes acamera..Iaddend..Iadd.77. A device according to claim 75, wherein said generating means includes means for generating data on an object distance..Iaddend..Iadd.78. A device according to claim 75, wherein said generating means includes photometric meansfor generating photometric data..Iaddend..Iadd.79. A device according to claim 78, wherein said photometric means includes means for generating a plurality of object brightness signals..Iaddend..Iadd.80. A device according to claim 78, wherein saidphotometric means includes means for generating photometric data on an entire picture
field..Iaddend..Iadd.81. A device according to claim 80, wherein said photometric means includes at least one of means for generating average photometric data on the entire picture field and means for generating partial photometric data on theentire picture field..Iaddend..Iadd.82. A device according to claim 75, wherein said generating means includes means for generating focal length data..Iaddend..Iadd.83. A device according to claim 82, wherein said generating means includes means forgenerating diaphragm data..Iaddend..Iadd.84. A device according to claim 75, wherein said generating means includes at least one of means for generating diaphragm data and means for generating data on a remote-control device..Iaddend..Iadd.85. A deviceaccording to claim 75, wherein said operation means includes means for obtaining a value indicating a likely main object as the determination value..Iaddend..Iadd.86. A device according to claim 75, wherein said operation means includes means forobtaining a peak value..Iaddend..Iadd.87. A device according to claim 75, wherein said operation means includes means for obtaining an intermediate value..Iaddend..Iadd.88. An optical system, comprising:
generating means for generating information for said optical system;
operation means for receiving an output from said generating means as an input value, obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and thethen-part membership function, both of which correspond to a plurality of rules representing a degree of influence of the input value on an operation of said optical system, obtaining a peak value from a plurality of fitting degree corresponding to therules, and obtaining a determination value as a result of inference; and
means for determining a condition associated with the operation of said optical system on the basis of the determination value..Iaddend..Iadd.89. An optical system according to claim 88, wherein said optical system includes acamera..Iaddend..Iadd.90. A method for determining a condition associated with an operation of image handling apparatus, comprising steps of:
generating information for said image handling apparatus;
receiving the information as an input value, and obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and the then-part membership function, both of whichcorrespond to a plurality of rules representing a degree of influence of the input value on an operation of said image handling apparatus;
obtaining a center of gravity value from a plurality of fitting degree corresponding to the rules, and obtaining a determination value as a result of inference; and
determining the condition associated with the operation of said image handling apparatus on the basis of the determination value..Iaddend..Iadd.91. A method according to claim 90, wherein said image handling apparatus includes acamera..Iaddend..Iadd.92. A method for determining a condition associated with an operation of image handling apparatus, comprising steps of:
generating information for said image handling apparatus;
receiving the information as an input value, and obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and the then-part membership function, both of whichcorrespond to a plurality of rules representing a degree of influence of the input value on an operation of said image handling apparatus;
synthetically evaluating a plurality of rules representing a degree of influence of the input value on an operation of said image handling apparatus; and
determining the condition associated with the operation of said image handling apparatus on the basis of the determination values..Iaddend..Iadd.93. A method according to claim 92, wherein said image handling apparatus includes acamera..Iaddend..Iadd.94. A method for determining a condition associated with an operation of image handling apparatus, comprising steps of:
generating information for said image handling apparatus;
receiving the information as an input value, and obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and the then-part membership function, wherein thethen-part membership function corresponds to a conversion rule obtaining from the input value two kinds of values converted in accordance with a degree of probable correctness and a value to weight the degree of probable correctness;
obtaining a degree of influence of the input value on an operation of said image handling apparatus by synthetically evaluating the two kinds of converted values; and
determining the condition associated with an operation of said image handling apparatus on the basis of the degree of influence..Iaddend..Iadd.95. A method according to claim 94, wherein said image handling apparatus includes acamera..Iaddend..Iadd.96. A method for determining a condition associated with an operation of an image handling apparatus, comprising steps of:
generating information for said image handling apparatus;
receiving the information as a an input value, and obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and the then-part membership function, both ofwhich correspond to a plurality of rules representing a degree of influence of the input value on an operation of said image handling apparatus;
obtaining a peak value from a plurality of fitting degree corresponding to the rules, and obtaining a determination value as a result of inference; and
determining the condition associated with the operation of said image handling apparatus on the basis of the determination value..Iaddend..Iadd.97. A method according to claim 96, wherein said
image handling apparatus includes a camera..Iaddend..Iadd.98. A control device for an image handling apparatus, comprising:
generating means for generating information for said image handling apparatus;
operation means for receiving an output from said generating means as an input value, obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and thethen-part membership function, wherein the then-part membership function corresponds to a two-dimensional conversion rule obtaining from the input value two kinds of values converted in accordance with a degree of probable correctness and a value toweight the degree of probable correctness, and obtaining a degree of influence of the input value on an operation of said image handling apparatus by one-dimensionally converting the two kinds of converted values; and
means for determining a condition associated with an operation of said image handling apparatus on the basis of the degree of influence..Iaddend..Iadd.99. An optical system, comprising:
generating means for generating information for said optical system;
operation means for receiving an output from said generating means as an input value, obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and thethen-part membership function, wherein the then-part membership function corresponds to a two-dimensional conversion rule obtaining from the input value two kinds of values converted in accordance with a degree of probable correctness and a value toweight the degree of probable correctness, and obtaining a degree of influence of the input value on an operation of said optical system by one-dimensionally converting the two kinds of converted values; and
means for determining a condition associated with an operation of said optical system on the basis of the degree of influence..Iaddend..Iadd.100. A method for determining a condition associated with an operation of image handling apparatus,comprising steps of:
generating information for said image handling apparatus;
receiving the information as an input value, and obtaining a fitting degree of the input value with respect to a then-part membership function in accordance with an if-part membership function and the then-part membership function, wherein thethen-part membership function corresponds to a two-dimensional conversion rule obtaining from the input value two kinds of values converted in accordance with a degree of probable correctness and a value to weight the degree of probable correctness;
obtaining a degree of influence of the input value on an operation of said image handling apparatus by one-dimensionally converting the two kinds of converted values; and
determining the condition associated with an operation of said image handling apparatus on the basis of the degree of influence..Iaddend. |
| Description: |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an improvement on a focus adjustment information forming device arranged to measure distances to objects appearing at a plurality of distance measuring points (or areas) set within a picture plane such as a photo-takingpicture plane or the like specified by optical means which is used for an optical system such as a camera and to be focus adjusted.
2. Description of the Related Art
The devices of the above-stated kind has been known as wide-field distance measuring devices, which have been disclosed, for example, in Japanese Laid-Open Patent Application No. SHO 58-201015 and U.S. Pat. No. 4,470,681. After thesedisclosures, devices arranged to prevent a distance measurement error due to a foreground has been disclosed in Japanese Laid-Open Patent Applications No. SHO 59-193307 and No. SHO 60-172008. In addition to these known devices, a device arranged toexclude any object located nearer than a given distance as an obstacle has been proposed in U.S. patent application Ser. No. 184,931, etc.
However, these known wide-field distance measuring devices have been incapable of accurately discriminating a nearby object from a nearby obstacle such as the ground and thus have often failed to give accurate focus adjustment information.
SUMMARY OF THE INVENTION
Such being the background situation, a principal object of the present invention is to provide a focus adjustment information forming device which is capable of forming reliable focus adjustment information by accurately discriminating themeasured distance value of an object to be focused on by optical means from other measured distance values obtained by a plurality of distance measuring areas including one located approximately in the central part of a picture plane.
To attain this object, a focus adjustment information forming device arranged according to this invention to measure distances to objects appearing at a plurality of distance measuring areas of a picture plane specified by optical means which hasits focal point being adjusted and to form information on adjustment of the focal point of the optical means, the plurality of distance measuring areas including a substantially central distance measuring area located approximately in the center of thepicture plane, comprises: first priority means for giving priority to a measured distance value which represents the nearest distance among measured distance values obtained from the plurality of distance measuring areas; a second priority means forgiving priority to the measured distance value obtained from the substantially central distance measuring area according to relations thereof to measured distance values obtained from distance measuring areas other than the substantially central distancemeasuring area when one of the measured distance values of the distance measuring areas other than the central distance measuring area represents the nearest distance; and focus adjustment information forming means for forming information on adjustmentof the focal point of the optical means on the basis of outputs of the first and second priority means.
Other objects and features of the invention will become apparent from the following detailed description of embodiments thereof taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing in outline the arrangement of an embodiment of the invention.
FIG. 2 is a flow chart showing the operation of the embodiment of FIG. 1.
FIG. 3 is a circuit diagram showing circuit arrangement of the embodiment for zone (area) comparison.
FIG. 4 is a circuit diagram showing a circuit arrangement of the embodiment made with a distance difference taken into consideration.
FIG. 5 is an analog circuit arrangement of the same embodiment.
FIG. 6 shows the input-output characteristic of an output circuit 81 of FIG. 5.
FIG. 7 is a circuit diagrams showing a circuit arrangement for attaining the same characteristic.
FIG. 8 is a circuit diagram showing a circuit arrangement for a probability addition to be performed on the basis of a distance difference for the embodiment shown in FIG. 1.
FIG. 9 shows the input-output characteristic of an output circuit 120 of FIG. 8.
FIG. 10 is a circuit diagram showing a circuit arrangement for attaining the same characteristic.
FIG. 11 is a circuit diagram showing by way of example the details of a peak detection circuit of FIG. 8.
FIG. 12 is a flow chart showing the operation of the circuit arrangement of FIG. 8 to be performed with a microcomputer included therein.
FIG. 13 is a flow chart showing by way of example a programmed operation of the same.
FIG. 14 is a circuit diagram showing a circuit arrangement for a probability subtraction to be performed on the basis of a distance difference for the embodiment shown in FIG. 1.
FIG. 15 is a circuit diagram showing a circuit arrangement made according to a probability array of the same embodiment.
FIG. 16 is a circuit diagram showing by way of example the arrangement of a barycenter computing unit of FIG. 15.
FIG. 17 is a flow chart showing the operation of the arrangement of FIG. 15 with a microcomputer included therein.
FIG. 18 shows by way of example a programmed operation of the same arrangement.
FIG. 19 is a block diagram showing the arrangement of FIG. 15 based on the Fuzzy theory.
FIG. 20 is a flow chart showing the operation of the arrangement of FIG. 19 with a microcomputer included therein.
FIG. 21 shows by way of example a programmed operation of the same.
FIG. 22 is a circuit diagram showing a circuit arrangement for obtaining an intermediate value through an analog computing operation using a distance difference for the embodiment shown in FIG. 1.
FIG. 23 is a circuit diagram showing by way of example a circuit arrangement for obtaining an intermediate value by a probability computation for the same embodiment.
FIG. 24 is a circuit diagram showing by way of example a normalizing arrangement for the circuit of FIG. 23.
FIG. 25 is a circuit diagram showing by way of example a probability array arranged to obtain an intermediate value by using a distance difference for the embodiment of FIG. 1.
FIG. 26 shows by way of example the arrangement of the distance and light measuring units of another embodiment of the invention.
FIGS. 27 to 29 show examples of positions of distance measuring points arranged within the photo-taking picture plane of the same embodiment.
FIG. 30 is a block diagram showing in outline the arrangement of a further embodiment of the invention.
FIG. 31 is a flow chart showing an operation using a measured light value for the same embodiment.
FIG. 32 shows by way of example a program for the operation of FIG. 31.
FIG. 33 shows the consequent membership functions of the same program.
FIGS. 34 and 35 are illustrations showing a shutter release operation to be performed with a camera held in vertical and horizontal postures.
FIG. 36 is a flow chart showing the same operation.
FIG. 37 shows an example where the same operation is performed according to a program.
FIG. 38 shows a mechanism arranged to give information on other postures of the camera.
FIG. 39 is a flow chart showing the operation of the same mechanism.
FIG. 40 shows an example where the same operation is performed according to a program.
FIG. 41 is a flow chart showing the operation of an embodiment of the invention arranged to use information on the use or nonuse of a flash device.
FIG. 42 shows an example where the same operation is arranged to be performed according to a program.
FIG. 43 shows a membership function for a reachable distance to be used for other embodiments of the invention.
FIG. 44 shows a weakly affirmative membership function to be used for other embodiments.
FIG. 45 shows a membership function for a remote-control received signal.
FIGS. 46 to 48 show membership functions based on distance differences.
FIG. 49 is a flow chart showing an operation performed by using aperture-value or focal-length information.
FIG. 50 shows by way of example a program of the operation of FIG. 49.
FIGS. 51 and 52 show membership functions of the aperture-value or focal-length information.
FIGS. 53 and 54 show membership functions for different focal lengths.
FIG. 55 is a flow chart showing an operation performed by using a focal length-using frequency for an embodiment of the invention.
FIG. 56 shows by way of example a program for the operation of FIG. 55.
FIG. 57 is a block diagram showing a further embodiment of the invention.
FIG. 58 shows distance measuring areas arranged within the viewfinder of the same embodiment.
FIGS. 59(a) to 59(e) show typical framing examples according to the Fuzzy rules of FIG. 21.
FIG. 60 shows Fuzzy rules employed by the embodiment of FIG. 57.
FIG. 61 schematically shows the Fuzzy rules of FIG. 60.
FIG. 62 shows by way of example a photographic framing to be employed in the event of having nearby obstacles on both sides.
FIGS. 63(a) and 63(b) show methods generally employed for a Fuzzy computation.
FIGS. 64, 66 to 68 and 70 show membership functions used by the embodiment of FIG. 57.
FIGS. 65, 69 and 71 show the formulas of the membership functions relative to the embodiment of FIG. 57.
FIG. 72 shows in outline the program of the same embodiment.
FIGS. 73 to 80 show the program examples of the same embodiment.
FIGS. 81, 82(a), 82(b), 83(a), 83(b), 84(a), 84(b), 85(a) and 85(b) show assembler program examples to be used for the same embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows in a block diagram an embodiment of this invention. The embodiment is arranged to measure distances to objects by means of three known distance measuring units 1, 2 and 3 through left, center (approximately in the center) and rightdistance measuring points (or areas) provided within a photo-taking picture plane (.Iadd.picture field) .Iaddend.specified by a photo-taking lens which is not shown. An analog voltage is produced as a result of the distance measurement. The nearer themeasured distance value DV1, DV2 or DV3 is, the lower the level of the analog voltage is. A computing circuit 4 receives the analog voltages from the distance measuring units 1, 2 and 3. The circuit 4 is arranged to compute and obtain lens driving(focus adjusting) information from the measured distance values, differences among them, information ANG about the posture of the camera, information ST about the use or nonuse of a flash device, information AV on an aperture value, etc. A focusadjusting system 5 is arranged to drive and control the lens according to the lens driving information from the computing circuit 4.
The details of the computing operation and the arrangement of the computing circuit 4 are as follows:
In the case of this embodiment, one of the measured distance values obtained from the three distance measuring points is selected through a computing operation which is performed on the basis of the following concept: Among these measureddistance values, the nearest distance value represents an object to be photographed in general. Hence, the nearest distance value is output as a general rule. However, in the case of "provided that" conditions where one of the left and right measureddistance values indicates a near distance, where the center measured distance value indicates a medium distance and where the other of the left and right measured distance values indicates a far distance, the measured distance value indicating the neardistance is regarded as representing a nearby obstacle such as a ground or the like located between the camera and the object to be photographed and, in that case, the computing circuit 4 outputs the center measured distance value, because: In such acase, it is highly probable that one of the distance measuring points is facing the ground with the camera held aslant or an obstacle such as a tree or the like is located nearby even if the camera is in a normal posture.
In a case where the computing circuit 4 of FIG. 1 includes a microcomputer, etc., the embodiment operates as shown in FIG. 2 which is a flow chart. In this instance, as criteria for determining whether the camera is under the above-stated"provided that" condition, the near distance is considered to be not exceeding 1.5 m, the medium distance to be between 2 m and 4 m and the far distance to be exceeding 5 m.
Referring to FIG. 2, the embodiment operates as follows: At a step #1: A check is made to see if the measured distance value (left measured distance value) obtained from the distance measuring unit 1 is not exceeding 1.5 m; if the measureddistance value (center measured distance value) obtained from the distance measuring unit 2 is between 2 m and 4 m; and if the measured distance value (right measured distance value) obtained from the distance measuring unit 3 is exceeding 5 m. If theseconditions are all satisfied, the center measured distance value is selected as the current measured distance information. If not, the flow proceeds to a step #2. At the step #2: A check is made to see if the measured distance value from the distancemeasuring unit 3 is not exceeding 1.5 m; if the value from the unit 2 is between 2 m and 4 m; and if the value from the unit 1 is exceeding 5 m. If these conditions are all satisfied, the center measured distance value is selected as the current measureddistance information like in the case of the step #1. If not, the flow proceeds to a step #3. At the step #3: A check is made to see if the value from the unit 3 is smaller than the value from the unit 2 and if the value from the unit 3 is smaller thanthe value from the unit 1. If these conditions are all satisfied, the measured distance value obtained from the distance measuring unit 3 is selected as the current measured distance information. If not, the flow proceeds to a step #4. At the step #4:A check is made to see if the value from the unit 1 is smaller than the value from the unit 2 and if the value from the unit 1 is smaller than the value from the unit 3. If these conditions are satisfied, the measured distance value from the unit 1 isselected as the measured distance information of that point of time. If not, the value from the unit 2 is selected as the measured distance information in the same manner as in the cases of the steps #1 and #2.
The above stated arrangement enables the camera of the AF type to more adequately bring the object into focus than the conventional AF camera of a narrow distance measuring field even with framing freely determined. Further, compared even withthe conventional camera of the kind measuring distances with a wide visual field, the embodiment is capable of eliminating the possibility of measuring a distance to a nearby obstacle such as the ground or the like by mistake. Therefore, a distance tothe object to be photographed can be correctly measured without any erroneous distance measurement.
In the case of FIG. 2, the flow chart shows a programmed operation. However, the operation can be also executed with an analog circuit arrangement. An example of that arrangement is shown in FIG. 3.
Referring to FIG. 3, the distance measuring units 1 to 3 shown in FIG. 1 are provided with output lines 31, 32 and 33 respectively. The output of each of these units is arranged to be in the form of an analog voltage which decreases accordinglyas the distance represented by the output is nearer. Distance information on the nearest distance is obtained from one of the output lines by means of diodes 34, 35 and 36 and a pull-up resistor 37. A window comparator 39 is arranged to make the levelof a signal line 40 high when a center measured distance value obtained through the output line 32 is within a given range (indicating a medium distance). Another window comparator 41 is arranged to make the level of a signal line 43 high when a leftmeasured distance value obtained through the output line 31 is above a given value (indicating a far distance) and to make the level of another signal line 42 high when it is less than the given value (indicating a near distance). A window comparator 44is arranged to make the level of a signal line 46 high when a right measured distance value obtained through the output line 33 is above a given value (indicating a far distance) and to make that of another signal line 45 high when it is less than thegiven value (indicating a near distance). An AND gate 47 is arranged as follows: In a case where, in respect to the above-stated "provided that" condition, the left indicates a near distance, the center a medium distance and the right a far distance,the AND gate 47 have all its inputs at high levels. In that case, therefore, the AND gate 47 makes the level of a signal line 48 high. An AND gate 49 is arranged as follows: In a case where, in respect to the above-stated "provided that" condition, theright indicates a near distance, the center a medium distance and the left a far distance, the AND gate 49 have all its inputs at high levels. In that case, therefore, the AND gate 49 makes the level of a signal line 50 high. An OR gate 51 is arrangedto make the level of a signal line 52 high in the event of the above-stated "provided that" condition. An analog switch 53 is arranged to output as lens driving information the center measured distance value obtained through the output line 32, insteadof the nearest measured distance value obtained through a signal line 38, in the event of the "provided that" condition."
The arrangement is simple as described above.
Each of the measured distance values is processed in the form of an analog signal the level of which increases accordingly as the measured distance is farther. However, the signal is not proportional to the absolute distance (at zero for 0 m andat infinity for an infinity distance) but is arranged to be reciprocal with the absolute distance suited for AF (automatic focusing). In other words, the signal is proportional to the depth of field.
Next, in cases where the criterional logic of the above-stated "provided that" condition part is changed, the embodiment operates as follows:
The nearest measured distance value is output as a general rule;
"provided that" the center measured distance value is output in cases where one of the left and right measured distance values indicates a distance considerably nearer than the distance indicated by the center measured distance value, where thecenter measured distance value indicates a medium distance, and where the other of the left and right measured distance values indicates a distance considerably farther than the distance indicated by the center measured distance value.
In other words, in respect to the above-stated logic, in a case where the left and right measured distance values indicate values in the opposite directions relative to the center measured distance value, the mode of rewriting the conditions intorelative values is used for the logic.
FIG. 4 shows a case where the logic is digitally embodied in an analog circuit. In FIG. 4, the parts having the same functions as the corresponding parts of FIG. 3 are indicated by the same reference numerals.
While the window comparators 44 and 41 of FIG. 3 are arranged to make a discrimination between a far distance and a near distance, this is changed according to the change in logic as follows in the case of FIG. 4: A differential amplifier 61 isarranged to output to a signal line 62 "the left measured distance value--the center measured distance value". As a result, a signal of a considerably low level flows to the signal line 62 when the left measured distance value indicates a considerablynearer distance than the center measured distance value. Then, a high level signal is generated in a signal line 64 via a window comparator 63. Further, in a case the left indicates a considerably farther distance than the center, a signal of aconsiderably high level flows to the signal line 62 to cause a high level signal to be generated in a signal line 65 via the window comparator 63. Meanwhile, a differential amplifier 66 is arranged to output and supply "the right measured distancevalue--the center measured distance value" to a signal line 67. As a result, a fairly low level signal flows to the signal line 67 when the right measured distance value indicates a considerably nearer distance than the center. Then, a high levelsignal is generated in a signal line 69 via a window comparator 68. When the right measured distance value indicates a considerably farther distance than the center, a considerably high level signal flows in the signal line 67 to cause a high levelsignal to be generated in a signal line 70 via the window comparator 68.
The ensuing processes of operation are similar to those of the arrangement of FIG. 3. The AND gate 47 makes the level of the signal line 48 high in cases where the level of the signal line 40 is high with the center measured distance valueindicating a medium distance, where the level of the signal line 70 is high with the right measured distance value indicating a farther distance than the center measured distance value, and where the level of the signal line 64 is high with the leftmeasured distance value indicating a nearer distance than the center measured distance value. Further, another AND gate 49 is arranged to make the level of the signal line 50 high in cases where the level of the signal line 40 is high with the centermeasured distance value indicating a medium distance, where the level of the signal line 65 is high with the left measured distance value indicating a farther distance than the center measured distance value, and where the level of the signal line 69 ishigh with the right measured distance value indicating a nearer distance than the center measured distance value. With the embodiment arranged in this manner, the center measured distance value is selected and output as lens driving information from theanalog switch 53 as in the case of the "provided that" conditions of the foregoing logic description.
With the distance difference included in the logic as described above, the arrangement of FIG. 4, unlike that of FIGS. 2 and 3, enables the device to make a discrimination without being restricted by the fixed distance measuring zones. In otherwords, it enables the device to correctly make a discrimination even in cases where the center measured distance value indicates a nearer distance or a farther distance than the medium distance. The details of this will be described later.
The arrangement to take the distance difference into consideration means consideration for a degree of blur that likely results from focusing on one side. In other words, a great difference in distance in the logic means that the use of one sidefor focusing would result in a blurred picture of the other side. In selecting one of the distance measuring points, this bears an important meaning.
An example of an arrangement for an analog discrimination of the "provided that" conditions of the logic described in the foregoing is as shown in FIG. 5. Referring to FIG. 5, an output circuit 80 is arranged to produce an output having afunction which increases the output when information indicating a medium distance is received and decreases it when information indicating a near distance or a far distance is received. As a result, a medium distance causes a larger output to beproduced into the signal line 40. An output circuit 81 likewise has a function which is arranged to give a larger output when its input is positive and large. When the right measured distance value indicates a farther distance than the center measureddistance value, the output circuit 81 produces a large output to a signal line 70. Another output circuit 82 has a function which gives a larger output accordingly as its input is negative and large. The output circuit 82 is thus arranged to produce toa signal line 69 a large output which increases accordingly as negative input increases. As a result, the signal line 69 generates an output which increases accordingly as the right measured distance value indicates a more nearer distance than thecenter measured distance value. A function circuit 83 is arranged in the same manner as the output circuit 82. Another function circuit 84 is arranged in the same manner as the output circuit 84.
The arrangement described above supplies the signal lines 40, 70, 69, 64 and 65 with signals similar to those of the digital arrangement of FIG. 4.
An example of arrangement for obtaining an input-output characteristic like that of the output circuit 81 is as follows: Referring to FIG. 6 which shows the characteristic, the axis of abscissa 91 shows an input (positive and large on theright-hand side). The axis of ordinate 92 shows an output. In relation to the input, the output value is produced at a function which is represented by a straight line 93. When the input is less than a value indicated by a point 94, the output valueis zero. The output is arranged to increase accordingly as the input increases from this point 94. FIG. 7 shows by way of example a circuit arrangement for obtaining this characteristic. Referring to FIG. 7, with an input voltage applied to a signalline 95, a voltage of a value corresponding to the above-stated point 94 is applied to a signal line 96. Diodes 98 and 99 are arranged to transmit to a signal line 100 the higher one of the voltages applied to the signal lines 95 and 96. A differentialamplifier 97 is arranged to produce a voltage difference between the signal lines 100 and 96 to a signal line 101. The signal line 101 thus carries information on a difference between the value of the higher one of the signal levels of the signal lines95 and 96 and the level value of the signal line 96. In other words, when the signal level of the signal line 95 is higher than that of the signal line 96, a difference by which the former is higher than the latter is produced to the signal line 101. Further, this circuit arrangement can be changed into the same arrangement as the above-stated output circuit 82 by arranging an inversion circuit in front of the diode 99 on the signal line 95 and by arranging the voltage of the zero-crossing point ofthe output circuit 82 to be applied to the signal line 96.
Again referring to FIG. 5, the circuit arrangement operates as follows: Multipliers 110 and 111 are arranged to compute the "and" parts of "provided that" conditions. A signal indicating the degree of satisfying the "provided that" conditions byits level is obtained at a signal line 113 from the outputs of the multipliers 110 and 111 which are output through signal lines 48 and 50 and supplied to an adder 112. A comparator 114 receives this signal makes a discrimination between satisfactionand nonsatisfaction of the conditions in two values. This determines whether or not the center measured distance value is to be selected by the analog switch 53.
According to this method, the "provided that" conditions are computed in an analog manner instead of a binary computation. This permits synthetic judgment of the conditions. In other words, this method has the following advantage: In a casewhere the center measured distance value is somewhat deviating from a medium distance, the center measured distance value is selected if the left measured distance value indicates a very near distance and if the right measured distance value an extremelyfar distance such as an infinity distance. In an opposite case where the left and right measured distance values are not indicating extremely far or near distances, the center measured distance value does not have to be selected. All elements of theabove-stated "provided that" conditions thus can be synthetically judged. In other words, synthetic evaluation of each condition prevents a possible misjudgment without setting a strict criterion for the "medium distance". For example, even in caseswhere a judged medium distance somewhat deviates from an ideal medium distance, a strong influence of other conditions would give the same result as mentioned above. This method is thus considered to allow a greater latitude to the logic.
FIG. 8 shows a circuit arrangement for carrying out the computing operation of the arrangement of FIG. 5 in a mode of "selecting a measured distance value which is probably most correct". The circuit arrangement thus makes selection byprobability.
In the case of this embodiment, the logic of "selecting the nearest one" is changed to a logic of "selecting a nearer distance at an increased rate within a range from the infinity to 1 m and at a lowered rate within a range nearer than 1 m". Further, a logic of "selecting the center measured distance value when the left and right measured distance values are larger than the center measured distance value in the opposite directions" is changed to a logic of "selecting the center measureddistance value at an increased rate when the left and right measured distant values are larger than the center measured distance value in the opposite directions". The arrangement of FIG. 8 then acts to "select one having a greater rate of selectionamong the measured distance values".
In other words, the arrangement of FIG. 8 is based on the following logic:
The rate where the left measured distance value is correct increases accordingly as the left measured distance value is close to 1 m;
The rate where the center measured distance value is correct increases accordingly as the center measured distance value is close to 1 m;
The rate where the right measured distance value is correct increases accordingly as the right measured distance value is close to 1 m;
The rate where the center measured distance value is correct increases accordingly as the left measured distance value farther than the center measured distance value and the right measured distance value is nearer than the center measureddistance value; and
The rate where the center measured distance value is correct increases accordingly as the right measured distance value is farther than the center measured distance value and the left measured distance value is nearer than the center measureddistance value.
The measured distance value to be selected is determined on the basis of the above-stated logic according to the overall selectable degrees of the three different measured distance values.
The circuit arrangement of FIG. 8 includes output circuits 120, 121 and 123, which are arranged to have such functions that cause them to output to signal lines 123, 124 and 125 signals at higher levels accordingly as the measured distance valuesare close to 1 m respectively. The details of the arrangement of these output circuits will be described later. The level of the signal line 123 is high if the left measured distance value is close to 1 m. As a result, a large amount of currentindicating "the rate of correctness of the left measured distance value" flows to a signal line 129 via a resistor 126. The level of the signal line 124 likewise is high if the center measured distance value is close to 1 m. As a result, a large amountof current indicating "the rate of correctness of the center measured distance value" flows to a signal line 130 via a resistor 127. The level of the signal line 125 is high if the right measured distance value is close to 1 m. Then, a large amount ofcurrent indicating "the rate of correctness of the right measured distance value" flows to a signal line 131 via a resistor 128.
Next, like in the case of FIG. 5, a distance difference between the left and right measured distance values is used as follows: A signal line 133 obtains information on the degree of a difference between the left and right measured distancevalues from the output circuits 81 and 83 via a multiplier 132 if the left measured distance value indicates a near distance and if the right measured distance value indicates a far distance. As a result a large amount of current indicating "the rate ofcorrectness of the center measured distance value" flows via a resistor 134 to the signal line 130. In cases where the right measured distance value indicates a near distance and where the left measured distance value indicates a far distance,information on the degree of difference is obtained on the signal line 136 via an amplifier 135 from the output circuits 82 and 84. In this case, a current indicating "the rate of correctness of the center measured distance value" flows in a largeamount to the signal line 130 via a resistor 137.
Resistors 138, 139 and 140 are arranged to convert into voltage values the added current values indicating "the rate of probable correctness" obtained through the above-stated computing processes. A peak detection circuit 141 is arranged toselect the highest one of the voltages obtained from the signal lines 129 to 131 and to make high the level of one of signal lines 142, 144 and 146 which correspond to the lines 129, 130 and 131. This circuit arrangement will be described in detaillater.
In a case where the left measured distance value is most probably a correct value, the level of the signal line 142 becomes high. Then, an analog switch 143 is turned on to allow the measured distance value coming through the output line 31 tobe output as lens driving information. When the center measured distance value is most probably the correct value, the level of the signal line 144 becomes high to turn on an analog switch 145. The switch 145 then allows the measured distance valuereceived from the output line 32 to be output as the lens driving information. If the right measured distance value is most probably the correct value, the level of the signal line 146 becomes high to turn on another analog switch 147. The switch 147then allows the measured distance value coming through the output line 33 to be output as the lens driving information.
The priority degrees thus can be given to the logic as in the case of the above-stated "provided that" conditions by changing the function provided within each of the output circuits 81 to 84 and 120 to 122 or by changing the value of each of theresistors 134, 137 and 126 to 128.
Each logic is thus synthetically judged by performing an adding operation on the values of "the rate of correctness". This means that a plurality of logic conditions are added up in an analog manner. Therefore, each logic does not have to beindependent of others. The criterion for the logic also does not have to be strict. In other words, the logic is acceptable even if it involves some contradiction. It is an advantage that the logic conditions of varied kinds can be added in a similarform.
The word "rate" as used in the foregoing description qualitatively means probability. However, the word differs from probability in the following points: Each of the logic conditions is independently computed without checking the above-statedindependency; and they are arranged to be computable without normalization and even when they include some graybody (ambiguity).
The input-output characteristic of the output circuit 120 of FIG. 8 is, for example, as described below:
FIG. 9 shows an example of the characteristic. The axis of abscissa 371 shows the input and the axis of ordinate 372 the output. In relation to the input, the output is produced with functions as represented by straight lines 373a and 373b. Upto a value of input indicated by a point 374 (which is 1 m in the case of this embodiment), the output gradually increases as shown by the straight line 373a. In the event of input values above this particular point, the output comes to graduallydecrease from this point 374 as shown by the straight line 372b. FIG. 10 shows a circuit arrangement for attaining this characteristic. Referring to FIG. 10, a signal line 359 is arranged to have an input applied thereto while a voltage correspondingto the point 374 is applied to signal lines 360 and 361. If the input value is less than the value of the point 374, since the voltage corresponding to the point 374 is applied to a signal line 360, by operations of an adder 358 which has a givenvoltage applied to a signal line 362, diodes 351 and 352, a differential amplifier 355, a diode 356 and a signal line 362, an output is produced on a signal line 364 in a manner as represented by the straight line 373a of FIG. 9. If the value of theinput to the signal line 359 is higher than the point 374, the voltage which corresponds to the point 374 and which is applied to the signal line 361 causes diodes 353 and 354, a differential amplifier 365, a diode 357 and the adder 358 to produce anoutput as represented by the straight line 373b of FIG. 9.
FIG. 11 shows an example of arrangement of the peak detection circuit 141 of FIG. 8. The level of an output line 154 becomes high when an input coming via an input line 151 is at a maximum value. The level of another output line 155 becomeshigh when an input coming via an input line 152 is at a maximum value. The level of an output line 156 becomes high when an input coming via an input line 153 is at a maximum value. In other words, when the input coming via the input line 151 is at amaximum value, the output level of a comparator 157 becomes high as the input via the input line 151 is larger than the input coming via the input line 152. Then, the output level of a comparator 158 also becomes high as the input via the input line 151is also larger than the input coming via the input line 153. As a result, the output level of an AND gate 159 becomes high to make the level of the output line 154 high. Further, when the input coming via the input line 153 is at its maximum value, theinput via the input line 153 is larger than the input coming via the input line 151. This causes the output level of a comparator 160 to become high. Then, since the input via the input line 153 is larger than the input coming via the input line 152,the output level of a comparator 161 also becomes high. As a result, the output level of an AND gate 162 become high to make the level of the output line 156 high. In a case where the input coming via the input line 152 is at a maximum value, thelevels of the comparators 157 and 161 and those of the AND gates 159 and 162 are low. In this case, therefore, the output level of a NOR gate 163 becomes high to make the level of the output line 155 high.
FIG. 12 is a flow chart showing the operation of the analog circuit of FIG. 8 to be performed with a microcomputer, etc. included in the circuit arrangement. Referring to FIG. 12, the operation is as follows:
At a step #21: For example, a register which is arranged to hold each of the measured distance values is set in its initial position. The flow of operation proceeds to a step #22. At the step #22: The left, center and right measured distancevalues are examined to see how much each of them differs from "1 m" which is regarded as a near distance in this embodiment. Each of these measured distance values is weighted according to the difference (an absolute value) detected. The weightingdegree increases accordingly as the value is close to 1 m. The weighted values thus obtained correspond to the outputs of the output circuits 120 to 122 of FIG. 8. The flow then proceeds to a step #23. At the step #23: A check is made for a differencebetween the center measured distance value and each of the left and right measured distance values. The center measured distance value is weighted according to degrees to which the left measured distance value is nearer than the center measured distancevalue and the right measured distance value is farther than the center measured distance value or according to the degrees to which the right measured distance value is nearer than the center measured distance value and the left measured distance valueis farther than the center measured distance value. The weighted values corresponds to the outputs of the multipliers 132 and 135 of FIG. 8. The flow proceeds to a step #24. At the step #24: The measured distance value which is most heavily weightedamong the weighted measured distance values of the left, center and right measured distance value is selected and output as the current lens driving information, which corresponds to the output of the peak detection circuit 141 of FIG. 8.
FIG. 13 shows an example of a program prepared for the flow of operation shown in FIG. 12. The left, center and right measured distance values are used as variables L, C and R respectively and the "rate" mentioned in the foregoing is computed. As a result of the computation, distance values are selected and output in the form of variables OUT. In this example, the program is prepared in a machine language something like the language called FORTRAN which is employed in coding for a computer.
Referring to FIG. 13, the first letters "L", "C" and "R" in codes LR, CR and RR respectively represent the left measured distance value, the center measured distance value and the right measured distance value. The letter "R" disposed in thesecond place in each of these codes LR, CR and RR indicates the above-stated "rate of probable correctness". Letters .alpha. and .beta. represent weighting functions. The function .alpha. becomes a maximum value when each of the left, center andright measured distance values is 1 m. The function beta increases the weighting degree accordingly as the difference between the center measured distance value and each of the left and right measured distance values increases further than a differencevalue of 2 m. Further, a code ABS means an absolute value. A code "max1" means selection of a maximum value. Therefore, ABS (L-1 m) means to obtain the absolute value of a difference obtained by subtracting 1 m from the left measured distance value. The expression max1 ((L-C)-2 m, 0) means selection of the larger one of "0" and a difference between 2 m and a computed difference value between the left measured distance value and the center measured distance value. Further "EQ" means equal.
Referring to FIG. 13, the details of the program are as follows: At a part corresponding to the step #21 of FIG. 12, an initial setting action is of course performed on each of the variables. At a part corresponding to the step #22, the left,center and right measured distance values are respectively weighted according to their differences from 1 m (by using the function .alpha.). They are thus converted into the variables LR, CR and RR which respectively include the rate of probablecorrectness. At a part corresponding to the step #23: The center measured distance value which has already been weighted by the function alpha is further weighted by using the function .beta. to obtain the variable CR according to a degree to which theleft and right measured distance values differ from the center measured distance value (with 2 m used as a datum point in the case of the embodiment). At a part corresponding to the step #24: One of the variables LR, CR and RR which is most heavilyweighted among them is selected. More specifically, if the variable LR is equal to max1 (LR, CR, RR) is equal to each other, the variable L which is the left measured distance value is output as lens driving information.
To facilitate the program, a peak selecting action is changed into a condition having the same value as the "max1".
Next, an arrangement for performing the operation of the arrangement of FIG. 8 in a subtracting mode is described below with reference to FIG. 14:
Referring to FIG. 14, the output of the output circuit 120 causes the level of the signal line 123 to increase accordingly as the left measured distance value is near to a given near distance. However, an inverting amplifier 170 sucks currentsout from the signal lines 130 and 131 by means of resistors 171 and 172 in such a way as to lower the rate of probable correctness of the center and right measured distance values. The level of the signal line 124 likewise becomes higher accordingly asthe center measured distance value is close to the given near distance. However, an inverting amplifier 173 sucks currents out from the signal lines 129 and 131 by means of resistors 174 and 175 in such a way as to lower the rate of probable correctnessof the left and right measured distance values. The level of the signal line 125 also increases accordingly as the right measured distance value is near to the given near distance. However, an inverting amplifier 176 sucks currents out from the signallines 129 and 130 by means of resistors 177 and 178 in such a way as to lower the rate of probable correctness of the center and left measured distance values.
Further, when the output of the signal line 136 indicates that the left measured distance value is farther than the center measured distance value and the right measured distance value is nearer than the center measured distance value, aninverting amplifier 179 causes resistors 180 and 181 to suck out currents from the signal lines 129 and 131 which carry signals indicating the rates of the left and right measured distance values. In cases where the output of the signal line 133indicates the right measured distance value is farther than the center measured distance value while the left measured distance value is nearer than the center measured distance value, an inverting amplifier 182 causes resistors 183 and 184 to suckcurrents out from signal lines 129 and 131 which carry signals indicating the rates of the left and right measured distance values.
As apparent from the above description of the arrangement of FIG. 14, the use of the current sucking subtraction mode in combination with the adding mode shown in FIG. 8 enables the device to perform about the same functions. Besides, thearrangement of FIG. 14 prevents the values (voltage values) from becoming excessively large in computing and obtaining a total of them.
FIG. 15 shows another embodiment, which is arranged as follows: In the arrangements of FIGS. 8 and 14, the "rate of probable correctness" is obtained from one of the signal lines carrying a signal of the "rate of probable correctness" byperforming an adding or subtracting operation. In the case of FIG. 15, however, the "rate" is obtained by performing an adding operation by using a plurality of signal lines.
For example, three signal lines for 0%, 50% and 100% are used in the following manner:
In the case of a strongly negative result of logic: A given value is added to the 0% signal line.
In the case of a weakly negative result of logic (rather negative): The given value is added to the 0% and 50% signal lines.
In the case of an indecisive result of logic: The given value is added to the 50% signal line.
In the case of a weakly affirmative result of logic: The given value is added to the 50% and 100% signal lines.
In the case of a strongly affirmative result of logic: The given value is added to the 100% signal line.
In making an overall judgment, the barycenter positions (%) of the three signal lines are obtained from the values obtained in the above-stated manner and then the line having the largest value of the barycenter position is selected.
Compared with the mode described in the foregoing, the above-stated mode of computation requires a greater number of computing processes. However, in the modes described in the foregoing, since the synthesization (or integration) of logic iscarried out by one of the signal lines, the affirmative and negative degrees are synthesized. In other words, these modes are incapable of discriminating the "rate of probable correctness" obtained in the event of a plurality of indecisive results oflogic from the "rate of probable correctness" obtained without any indecisive result of logic. Therefore, an ambiguous (gray) result of logic might be selected by mistake. Whereas, in the mode of FIG. 15, the "rate" of the 50% signal lines increases inthe event of many indecisive results of logic. Then, in carrying out the barycenter computation, "0%" negative or "100%" affirmative becomes "25%" or "75%." In other words, the negative and the affirmative are computed in a thinned state. It is,therefore, an advantage of this mode that the computing operation is carried out including the above-stated indecisive and weak affirmative results and a weak negative result.
This mode can be extended into the so-called "Fuzzy theory" which has recently become popular.
In the arrangement of FIG. 15, the single signal line of "the rate of probable correctness" used in the arrangement of FIG. 8 is replaced with five signal lines including 0%, 25%, 50%, 75% and 100% signal lines.
The level of the signal lines 123 becomes higher and the output level of an amplifier 200 increases accordingly as the left measured distance value is near to the near distance. The resistor 126 which is singly disposed in the signal line 123 inthe case of FIG. 8 is replaced with a resistor block 201. The resistor block 201 consists of five resistors of five different resistance values which are connected to five signal lines for five different "rates of likely correctness", including: A 100%signal line arranged to have a large current with a small resistance and a 0% signal line arranged to have a small current with a large resistance. Information about the degree of likeliness as to whether the center measured distance value is the neardistance is likewise supplied via an amplifier 202 to a resistor block 203 including five signal lines provided for determining the rate of the center measured distance value. Information about the degree of likeliness as to whether the right measureddistance value is the near distance is also supplied via an amplifier 204 to a resistor block 205 including signal lines provided for determining the rate of the right measured distance value.
The resistance difference among the above-stated resistor blocks is, so to speak, a "ratio" between one way of thinking that "the left measured distance value is absolutely correct and should be selected" and another way of thinking that,although it is logically correct, "there is a possibility that a measured distance value other than the left measured distance value might be correct, that is, the left measured distance value might be not selected" in a case where the left measureddistance value is, for example, logically determined to be the near distance. Therefore, the internal resistance ratios of resistor blocks 206 and 401 which are provided for supplying currents from signal lines 133 and 136 to the five signal linesarranged to determine the rate of the center measured distance value may, in some cases, differ from those of the resistance ratios of other resistor blocks 201, 203 and 205. Especially, as mentioned in the foregoing, the priority logic arrangement of"provided that ---" conditions results in a lower resistance on the 100% side and a higher resistance on the 0% side. Further, the average internal resistance value of each resistor block is arranged to be low in the case of a strong logic depending onthe strength of the whole logic, i.e. according to the weight of the result of logic.
The signal line groups provided of three kinds carrying information on different rates to be selected are arranged to supply information on the rates to be selected to signal lines 208, 209 and 210 through barycenter computing units 207 which arearranged to compute applicable barycenters respectively. The peak detection circuit 141 is arranged to obtain the highest selectable rate of the left, center and right measured distance values. The level of one of the signal lines 142, 144 and 146 thenbecomes high to cause the output of the peak detection circuit 141 to be output as lens driving information from one of the analog switches 143, 145 and 147.
FIG. 16 shows by way of example the details of each of the above-stated barycenter computing unit 207.
The signal lines for the selective rates of 0 to 100% (five signal lines for 0%, 25%, 50%, 75% and 100% in this specific case) are connected to a resistor 221 in positions from the left to the right in order of rate. As a result, a current isdivided and shunted to signal lines 222 and 223 in a ratio according to the connecting positions of the five signal lines. The shunted currents are supplied to a divider 224, which is arranged to produce an output according to the dividing ratio betweenthe input currents. The output of the divider 224 is supplied to a signal line 225 in the form of a voltage. Such being the arrangement, 100 parts of voltage is produced to the line 225, for example, if the current is flowing only to the position of100%, and 50 parts of voltage is produced if the current is flowing only to the position of 50%. This arrangement enables the unit 207 to give a signal for the "rate to be selected" on the basis of the synthetic logic. .Iadd.The selecting operation canbe called a defuzzifying operation and unit 207 can be called a defuzzifier operation circuit..Iaddend.
With a plurality of signal lines for 0 to 100% provided as mentioned above, even such a measured distance value that has a gray result of logic can be computed. This is an advantage in case where the rates are to be influenced by varied numberof logics. In other words, the arrangement to have the plurality of signal lines is advantageous, for example, in cases where one logic is used for determining the rate of each of the left and right measured distance values and three logics for that ofthe center measured distance value like in the case of the preceding example described in the foregoing, because: For an accurate computation of probability, the result of computation must be normalized for each logic. In the case of the exampledescribed above, the probability of the center must be increased by affirmation, decreased by ambiguity and decreased by denial while those of others must be decreased and increased accordingly (although it depends also on the involutional relation oflogic). In the case of the ambiguous logic, the decrease and increase must be different from the increase and decrease under affirmative and negative conditions. In short, the accuracy of computation cannot be maintained without accurate and complexoperations on the probability of the cases according to the logical results (especially in the event of many cases and many gray logics).
In the above-stated example, the provision of, for example, the 50% signal line enables the device to thin down the degrees of affirmation and denial for each of the rates. Further, as regards affirmation or denial of each rate, a distributionconstant having some value in the 50% signal line permits normalization of distributed values through comparison of the barycenters of them.
FIG. 17 is a flow chart showing the operation of the above-stated arrangement of FIG. 15 with a microcomputer, etc. included therein. Referring to FIG. 17, the operation is as follows: At a step #31: Initial setting is performed. At a step #32:The left, center and right measured distance values are checked for their differences from "1 m" which is considered to be a standard near distance. Each of them is weighted within its array (of signal lines) according to the difference thus found (bythe resistor blocks 210, 203 and 205 of FIG. 15). At a step #33: With importance attached to the difference of the center measured distance value from the left and right measured distance values, the center measured distance value is weighted within itsarray (the resistor blocks 206 and 401 of FIG. 15) according to degrees to which the left measured distance value is nearer and the right measured distance value is farther than the center measured distance value, or the right measured distance value isfarther and the left measured distance value is nearer than the center measured distance value. .Iadd.Such degrees can be called fitting degrees. .Iaddend.Then, the flow proceeds to a step #34. At the step #34: The barycenters of the weighted left,center and right measured distance values are obtained from within their arrays respectively. At a step #35: The measured distance value having the largest barycenter (.Iadd.center of gravity) .Iaddend.is selected and output (the output of the peakdetection circuit 141 of FIG. 15).
FIG. 18 shows an example of a program prepared for the flow of operation shown in FIG. 17. In this case, the array of the 0 to 100% signal lines is expressed as an array 0 to 100 indexes ($) for computation. Further, the functions of theresistor blocks 210, 203, 205, 206 and 401 are expressed as the arrays of .alpha.$ and .beta.$.
Referring to FIG. 18, the details of the program are as follows: At a part corresponding to the step #31 of FIG. 17, initial setting of all variables is performed. At a part corresponding to the step #32: The left, center and right measureddistance values are weighted within their arrays (by a multiplying operation with the function .alpha. for 0 to 100). They are thus converted into variables LR, CR and RR which respectively include the "rate of probable correctness". At a partcorresponding to the step #33: According to the degrees to which the left and right measured distance values deviate in different directions, weight is further attached to the center measured distance value within its array (by a multiplying operationwith the function .beta. for 0 to 100). The center measured distance value is thus made into the variable CR. At a part corresponding to the step #34: The barycenters of the added left, center and right measured distance values which are weighted for0 to 100 are obtained from within their arrays respectively. At a part corresponding to the step #35: The valve having the largest barycenter is selected and output.
FIG. 19 shows a circuit arrangement based on a higher notion than the arrangement of FIG. 15. Referring to FIG. 19, output circuits 230 have functions for "outputting a larger value accordingly as the measured distance value is close to 1 m"like in the case of the output circuits 120 to 122 of FIG. 15. The circuits 230 are thus arranged to output via signal lines 231 to 233 such signals that indicate degrees to which the left, center and right measured distance values are close to 1 mrespectively. An output circuit 234 has a function for varying the rate according to the degrees of the measured distance values. The circuit 234 corresponds to the resistor blocks 201, 203 and 205 of FIG. 15. Function circuits 235 to 237 whichcorrespond to the amplifiers 200, 202 and 204 of FIG. 15 are arranged to multiply the degree outputs by the function output of the circuit 234. A computer 238 which is arranged to add to the current rate a rate change obtained as a result of logic. This computing operation corresponds to the operation of adding currents by the resistor blocks of FIG. 15. Output circuits 239 have functions for "outputting a larger value accordingly as the measured distance value is farther than the center measureddistance value" like in the case of the output circuits 82 and 83 of FIG. 15. Multipliers 241 are arranged to perform multiplying actions corresponding to the "and" included in the same logic conditions as those of the multipliers 132 and 135 of FIG.15. An output circuit 242 has a function for changing the rate on the basis of the same logic as that of the resistor blocks 206 and 401 of FIG. 15. A computer 243 is arranged to multiply the degree outputs of the circuits 241 by the function output ofthe circuit 242. A computer 245 is arranged to change the value of rate with the output of the computer 243.
The ensuing operation of the arrangement of FIG. 19 is similar to that of the arrangement of FIG. 15 and one of the measured distance value is eventually output as lens driving information.
Again referring to FIG. 19, the arrangement is described according to the Fuzzy theory as follows: The output circuits 230, 239 and 240 correspond to condition membership functions in the Fuzzy rules. .Iadd.Such condition membership functionscan also be called if-part membership functions. .Iaddend.The output circuits 234 and 242 are consequent membership functions. .Iadd.Such consequent membership functions can also be called then-part membership functions. .Iaddend.In the above-statedarrangement, the computing operations of the computers 235, 236, 237, 243 and 244 are performed in accordance with the method of Larsen to obtain the consequent membership functions from the condition membership functions. .Iadd.Computers 235, 236, 237,243 and 244 can be called Fuzzy computers or Fuzzy operation circuits. .Iaddend.The convolution of rules performed by the computers 238 and 245 corresponds to computation of an algebraic sum. (While a simple adding operation is performed by thearrangement described, a maximum value "1" must be computed, in theory.) Further, an algebraic product is used for the composition of conditions performed by the multiplier 241.
Other effective methods include, for example, the method listed below (an excerpt from a thesis of Mr. Mizumoto of Osaka Electric Communication College, disclosed at the 5th Knowledge Engineering Symposium):
______________________________________ Product obtaining operation: Logical product: X Y = min (X, Y) Algebraic product: X .multidot. Y = X * Y Bounded product: X .multidot. Y = max (0, (X + Y - 1)) Drastic product: X Y = X * Y (when X =1 or Y = 1) 0 (when X .noteq. 1 and Y .noteq. 1) Sum obtaining operation: Logical sum: X Y = max (X, Y) Algebraic sum: X Y = X + Y - X * Y Bounded sum: X .sym. Y = min (1, (X + Y)) Drastic sum: X Y = X + Y (when X = 0 or Y = 0) 0 (when X .noteq.0 and Y .noteq. 0) ______________________________________
The computing operation methods for obtaining consequent membership functions from the condition membership functions, include a method of using sum obtaining operation in composing (combining) rules, i.e. a method of adding rates of probablecorrectness (adding "0" if totally unknown), which are as shown below: ##EQU1##
Further, there are methods of using a product obtaining operation in composing (combining) rules. This is based on the following concept: In the event of a totally unknown part, "1" is used. The number of unknown parts decreases accordingly asconditions are established to give the consequent membership functions. The methods based on this concept includes: ##EQU2##
FIG. 20 is a flow chart showing the operation of the arrangement of FIG. 19 with a microcomputer, etc. included in the arrangement. Referring to FIG. 20, the flow of operation is as follows At a step #41: Weight is attached to each of the left,center and right measured distance values according to degrees to which they are deviating from 1 m. At a next step #42: The center measured distance value is weighted according to degrees to which the left and right measured distance values aredeviating from the center measured distance value. At a step #43: Among these measured distance values, the most heavily weighted value is selected and output.
FIG. 21 describes the flow of operation of FIG. 20 according to the Fuzzy theory. In FIG. 21, a term "near distance" means the distance of 1 m as mentioned in the foregoing and is a function which takes a maximum value of "1". A function.alpha. gradually takes "0 to 1" for 0 to 100%. A function .beta. somewhat acutely takes, for example, 0 to 1 for 50 to 100%. The strengths of two logics are differentiated from each other by a difference between the functions .alpha. and .beta..
The details of the operation of FIG. 21 are as follows: At a part corresponding to the step #41: The left, center and right measured distance values are respectively weighted according to the degrees to which they are close to the near distance 1m. Then the rate of probable correctness of each measured distance value is computed with the function .alpha. to obtain variables LR, CR and RR. At a step corresponding to the step #42: Weight is further attached to the center measured distance valueaccording to the degree to which the difference of the center measured distance value from the left and right measured distance values is large and positive (i.e. the degrees to which the left and right measured distance values deviate from the centermeasured distance value, or relative relations of the left, center and right measured distance values in respect to far (near), medium, and near (far) distances. Then, the rate of probable correctness of the weighted center measured distance value iscomputed with the function .beta. to obtain the variable CR. At a part corresponding to the step #43: Among the weighted variables LR, CR and RR, the most heavily weighted one is selected and output.
In all the examples described, one of the distance values obtained from the left, center and right distance measuring areas is selected as a result of distance measurement. In the following, however, a method of employing an intermediate valuebetween these measured distance values as the result of distance measurement: FIG. 22 shows an arrangement for carrying out this method. This arrangement is described as a modification of the analog computing arrangement of FIG. 5.
The use of the signal line 113 for the center measured distance value gives a signal showing a better rate. Therefore, a value between the center measured distance value and a distance value nearest thereto is produced in an analog manneraccording to the result obtained from the signal line 113. A variable resistor 260 is provided for this purpose. The resistor 260 is arranged to select the nearest measured distance value obtained from the signal line 38 when the level of the signalline 113 is zero and to select the center measured distance value obtained from the output line 32 when the signal line 113 is at a maximum level. The variable resistor 260 thus operates in a servo-like manner according to the level of the signal line113. When the signal line 113 is at a medium level, the resistor 260 produces an intermediate distance value between the nearest distance value and the center measured distance value.
The selection of an intermediate value in this manner might bring both distance measuring concerned out of focus in the event of shallow depth of field. However, ordinary photographing operations generally have a certain depth of field to give agood picture with both areas in focus.
FIG. 23 shows a circuit arrangement which is a modification of the arrangements of FIGS. 8 and 14 and is arranged to output an intermediate value. Referring to FIG. 23, the processes of operation up to the computation of the rates of the signallines 129, 130 and 131 are about the same as in the preceding example. This arrangement includes a normalizing circuit 261, which is arranged to normalize the signals of three rates and to output the normalized signals to three signal lines 262, 263 and264, in such a way as to make the total of these three rates into "1". Multipliers 265, 266 and 267 are arranged to multiply the measured distance values by these three normalized signals. The outputs of the multipliers 265, 266 and 267 are supplied toan adder 268 to obtain a weighted average of the measured distance values. The weighted average value is output as lens driving information. The arrangement thus makes a synthetic or integral judgment on the three measured distance values to give apicture which is in focus all over.
FIG. 24 shows by way of example the details of the above-stated normalizing circuit 261 of FIG. 23. Reference numerals 271, 272 and 273 denote positive rate signals. Multipliers 274, 275 and 276 multiply these rate signals by the signal of asignal line 280. The results of the multiplying actions are output to signal lines 277, 278 and 279. The three signals thus obtained are added together through resistors 281, 282 and 283. An inverting amplifier 284 is arranged to control the signalline 280 in such a way as to make the sum of these three signals into "1".
FIG. 25 shows a circuit arrangement which is arranged to output an intermediate value in computing the distribution probability in a manner as shown in FIG. 15. The circuit parts up to the part 210 are identical with those of FIG. 15. Parts 261to 268 are arranged to obtain a weighted average value in the same manner as in the case of FIG. 23.
The arrangement to obtain a weighted average after completion of rate computation as in the cases of FIGS. 23 and 25 enables the device to give a correct output with the three values selected through the complex computing operation irrespectivelyof variations taking place in the rates of the three values.
The arrangements described in the foregoing eliminate the adverse effects of nearby obstacles such as the ground, etc. by means of the measured distance values and information on differences between them. However, information of other kinds arealso usable as means for making an effective discrimination.
An example of arrangement for making the discrimination by means of a measured light value (brightness) is as follows: FIG. 26 shows by way of example the arrangement of a light measuring sensor of a camera. The illustration includes a camerabody 300; and distance measuring units 1, 2 and 3 which are also shown in FIG. 1. The units 1, 2 and 3 are arranged to measure distances in the directions 301, 302 and 303 respectively. Known light measuring units 304, 305 and 306 are arranged tomeasure light also in the directions 301, 302 and 303.
FIG. 27 shows a photographing frame of the camera in relation to the distance and light measuring directions. The measuring directions 301, 302 and 303 are arranged to be not only laterally spreading as shown but also vertically spreadingrelative to a photographing picture plane 307, because: In some cases, framing requires to have the picture plane in a vertical posture as shown in FIG. 28. The spreading arrangement of measuring directions then permits distance measurement in thelateral directions with the picture plane in the vertical posture.
For an improved degree of accuracy, the number of measuring points may be increased from three points to five or more points as shown in FIG. 28. However, the increase of measuring points is not easy in terms of cost and, therefore, should bedetermined according to the purpose for which the camera is designed. Meanwhile, the discrimination of a nearby obstacle such as the ground from other objects is necessary in all cases. In view of this, the following description is given on theassumption that the number of measuring points is three.
FIG. 30 shows by way of example the arrangement of the above-stated embodiment. In this case, the camera is controlled by measuring distances and brightness in three directions. An average light measuring unit 308 is arranged to obtain theaverage of three measured light values received from the light measuring units 304, 305 and 306. The average value is output to a signal line 309. A computing circuit 310 is arranged to selectively output a measured distance value as lens drivinginformation. Compared with the arrangements described in the foregoing, the computing circuit 310 receives a greater number of inputs including the above-stated three measured light values and the average measured light value of the signal line 309 inaddition to measured distance values.
FIG. 31 is a flow chart showing the operation of the above-stated embodiment with a microcomputer, etc. included in the arrangement described. Referring to FIG. 31, the operation is as follows: At a step #51: The left, center and right measureddistance values are weighted according to degrees to which they deviate from 1 m. At a step #52: The center measured distance value weighted according to degrees to which the left and right measured distance values differ from the center measureddistance value. At a step #53: If one of the left and right measured distance values indicates a near distance and if the brightness of the other side is high, the | | | |
