GB1058720A - Apparatus for character recognition - Google Patents

Abstract

1,058,720. Automatic character reading. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 23, 1963 [Dec. 24, 1962], No. 50603/63. Heading G4R. In a character reading apparatus the character area is scanned by a raster of horizontal lines and the signals obtained are sampled to obtain black and white representations which are used to detect shape elements or features and the character is identified from the order of detection of those features. The character field 10 Fig. 1 (not shown) is scanned by a series of horizontal strokes by C.R.T. scanner 11 and the video signals from photo-cell 13 are applied to a pulse generator 14 to obtain binary black and white signals. During each horizontal stroke multivibrator 15 produces 8 pulses. These pass to a counter having three stages 71, 72, 73 the last controlling the sweep circuit 20 to fly-back and start the next line. The outputs of the counter stages T2, T3 define the four horizontal zones α, #, γ, 8 and the left and right halves L, R. The outputs of these stages are gated together to indicate the zones α, #, γ, # by signals on corresponding leads. The zone signals are gated with the output of pulse generator 14 to obtain the following feature signals: IL (a vertical line in the left portion of the field) when four successive scan lines contain a black signal in zone α or the same in zone #; IR (a vertical line in the right portion of the field) when four successive scan lines contain a black signal in zone 8 or the same in zone γ; H (a horizontal line) when any scan line contains four consecutive black signals; and 0 (a gap between two portions of a numeral) when in any scan line black signals are separated by one or more white signals. The consecutive black or white signals required for the above indications are counted by trigger stages, e.g. 22, 23 connected to count four consecutive black signals in one scan line. Once a feature has been identified the corresponding output circuit is disabled until another feature has been identified. This is effected by gates and triggers 70-82. The feature signals, in the form of successive pulses each on an appropriate one of four leads are applied to an identifying circuit, Figs. 2a, 2b (not shown). Since the sequence of detection of the features is the basis for recognition each feature lead is connected to the input of a 6-stage shift-register, all the registers being stepped together. The outputs, each of which indicates a feature and its order of arrival, are combined in a diode matrix to identify the character.