Optical character recognition system including a matrix of scanned photosensitive elements

Claim 1

An optical character recognition system comprising, a photohead having a matrix of photosensitive elements providing signals the relative polarity of which is dependent upon the light to which they are exposed, a plurality of detectors each responsive to signals from first and second sets of a group of said elements a different group for each detector, wherein each said detector includes a signal comparator, a first signal assessor and a second signal assessor, the first signal assessor providing onE input signal for the comparator corresponding to a most negative signal of signals from the said first set and a second signal assessor providing another input signal for the comparator corresponding to a most positive signal of signals from the said second set the comparator being arranged to provide an output signal indicative of the detection of a feature when the most negative signal from the first set is more positive than the most negative signal from the second set, and recognition indicator means responsive to such detection for providing a final output signal indicating the recognition of a character consequent upon the detection of a number of features common to that character.