Image Number 2 for United States Patent #6452136.
An apparatus that determines properties of a cooktop is provided. The cooktop includes a cooktop surface and a vessel that is selectively placed on the cooktop surface. The apparatus comprises a radiation sensor positioned below the cooktop surface. The radiation sensor senses at least a portion of, at least one of reflected radiation and ambient radiation that are provided above the cooktop surface and that pass through the cooktop surface. The radiation sensor also generates a detected radiation signal based on the sensed radiation. A processor is connected to the radiation sensor, and the processor determines properties of the cooktop from analyzing the detected radiation signal.