Automatic, self-diagnosing, electro-optical imaging system

Abstract

An electro-optical imaging system is disclosed which automatically self-diagnoses the operations of its photosensor and its video processing circuitry during each of first and second modes of operation of a processor, when no object is being imaged. In a preferred embodiment, a power supply is controlled by the processor to prevent a light source from illuminating a reference background during the first mode of operation and to enable the light source to illuminate the reference background during the second mode of operation. The photosensor sequentially develops first and second signals respectively proportional to the intensity of reflected light received from the reference background during the first and second modes of operation. The video processing circuitry is responsive to the first and second signals for sequentially developing respective first and second data signals. A first circuit is responsive to the first and second signals for sequentially developing first and second test signals respectively proportional to the average values of respective portions of the first and second signals. A second circuit is responsive to the first and second data signals for sequentially developing third and fourth test signals respectively representative of predetermined portions of the first and second data signals. The processor is selectively responsive to the first, second, third and fourth test signals for automatically testing the operation of each of the photosensor and video processing circuitry during each of the first and second modes of operation.