Image Number 3 for United States Patent #7672020.
Method for duplex printing on transparencies to create auto-stereoscopic enhancement to rendered images. On one side of the transparency is provided a uniform halftone with a selected median spatial frequency as printed. On the other side, the image for enhanced rendering consisting of two partitions is printed: that partition which is to be perceived as the background is printed using a halftone with spatial frequency equal to the median plus some delta x, while the other image partition is printed using a halftone with a spatial frequency equal to the median minus the same delta x. The spatial frequency difference creates a corresponding shift-magnification factor M with an amplified total depth of the shift-magnification factor M times the thickness of the transparency.