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1320243 Character recognition RECOGNITION EQUIPMENT Inc 20 Oct 1970 [20 Oct 1969] 49740/70 Heading G4R A character is recognized using an array of sensors, vector boundary-direction signals being derived from black and white signals and used to derive quadrature-limited, curvature feature, binary signals which are stored and compared with character masks. Signals from a matrix of photocells seeing a moving character are quantized to black/white by comparing each with the average of the signals from surrounding photocells followed by thresholding, the results being stored in a shift matrix. When the character is in the matrix, the matrix is successively shifted up, left and right so that for each of nine overlapping zones of the character in turn, each bit in turn can be sensed together with surrounding bits by logic circuitry to detect elementary boundary directions (perhaps more than one at a given bit position). A white border is simulated in this logic circuitry to isolate top data from bottom and left from right. Sequences of three and five directions are sensed by further logic circuitry, which is also controlled by a vector sequencer responsive to the elementary boundary directions present to ensure that, in the event of there being more than one at a given position, all are dealt with in turn. This further logic circuitry feeds feature accumulators which use logic to detect the following features: convex and concave curves in four quadrants with a yes/no sharpness indication for each quadrant, horizontal, vertical, right sloping and left sloping straight lines, stops and nodes. Bidirectional counters with weighted inputs are also use in detecting sharpness, and counters are also used in detecting stops, nodes and straight lines. The resulting feature signals are then stored, and when the signals for all the zones have arrived resistor masks combine the features to identify the character, masks being provided for features which-should be present and features which should be absent for respective characters, there being a plurality of each sort of mask for each possible character. Resulting voltages relating to respective possible characters are amplified, except that voltages below a given level are replaced by a very low voltage, an upper clipping level also being imposed. The largest resulting voltage identifies the character, being detected by a null detector fed with a staircase voltage triggered via a threshold detector. Operation of the system