GB1324123A - Device for recognising characters and structures - Google Patents

Abstract

1324123 Character recognition systems KOMBINAT ROBOTRON VEB 19 Jan 1971 61128/70 Heading G4R In a character recognition system the degree of openness of the character is determined. This is defined as the ratio of the length a of the character opening to the arc length s, Fig. 2. The openness is determined in each of four directions Z1-Z4, Fig. 5. The openness may have more than one value in any one direction; thus in direction Z2, Fig. 5, there is one openness value for the upper segment of the 5 and one for the lower segment. The system also determines whether the segment occupies the entire width of the character in the viewing direction (e.g. as in directions Z1, Z3) or is to left or right of the viewing direction. It is also determined whether the segment is concave or convex in the viewing direction. Signals representing the values of these various parameters are passed to recognition circuitry (not described). The character is sensed by, for example, a matrix or line of photo-cells or a scanning cathode-ray tube and photomultipliers. The resulting signals are placed in a store comprising a stack of nine matrices each of n Î m cells. When a black part of the character is sensed a mark is stored in the corresponding cell x, y of one matrix. A mark is also recorded on each of the other matrices but in cells x + r, y + s, r and s being different for each matrix. Thus each matrix finally stores the character in 9 spatially displaced forms so that selection of a single read-out line causes read out of a selected bit cell x, y of each matrix, providing a signal equivalent to read out of cell x, y of the first matrix and of the 8 cells surrounding it. The circuitry described subsequently searches for a starting point of the character and thereafter follows the outline of the stored character. Small gaps are ignored, large gaps being assumed to indicate the end of a character or segment of a character. The end position co-ordinates are stored and used to calculate the open length a, Fig. 2. The value and the signals read from the store pass to circuits employing counters, threshold units, gates, &c., to provide the parameter values referred to above.