Character recognition apparatus

Claim 2

Character recognition apparatus which comprises a. means to obtain a peripheral distribution pattern of an unknown input character by projecting the density distribution of said character on at least one axis, b. means to obtain an amplitude spectrum pattern of said peripheral distribution pattern, c. memory means for storing a number of standard amplitude spectrum patterns corresponding to a number of standard characters, d. comparator means for comparing said standard spectrum patterns stored in said memory means and said amplitude spectrum pattern of said unknown input character and providing a correlation value between both the patterns, and e. output circuit means for deriving as the unknown input pattern the standard character corresponding to the standard amplitude spectrum pattern which attains the maximum one of a number of correlation values obtained by said comparator means.

Claim 3

Character recognition apparatus according to claim 1, further including means to sample a spectral component of a specific part within an angular frequency region 0 - 2 pi of said amplitude spectrum pattern of said unknown input character, the angular frequency region of each of the standard spectra corresponding to said standard characters stored in said memory being the same as the sampled frequency region of said unknown input character at said specific part.

Claim 4

Character recognition apparatus according to claim 2, wherein said angular frequency region of said specific part ran as from 0.2 radian to 1.4 radian.

Claim 5

Character recognition apparatus according to claim 1, wherein said at least one axis from the projection consists of the axes orthogonal to each other, the vertical and horizontal density distributions of said unknown input character being respectively projected on said axes.

Claim 6

Character recognition apparatus which comprises a. a photoelectric converter which periodically scans an unknown input character in successive scanning periods to convert it into an electric signal, b. a quantizing circuit connected to said photoelectric converter which quantizes said electric signal into two values in response to detected signal levels, c. a gate circuit connected to said quantizing circuit which opens and closes a circuit providing a clock signal in response to the output signal levels of said quantizing circuit, d. a counter connected to said gate circuit for counting the outputs of said gate circuit during each scanning period, e. a first buffer memory connected to said counter which stores an output of said counter in the form of a projection pattern representative of a peripheral distribution, f. A Fourier transform unit connected to receive an amplitude spectrum from said buffer memory, g. a buffer spectrum memory which stores an output of said Fourier transform unit, h. main memory means for storing amplitude spectra corresponding to a number of standard characters i. comparator means for calculating the degree of correlation between the amplitude spectrum from said main memory and the amplitude spectrum of said buffer spectrum memory, j. output circuit means connected to said comparator means for providing the standard character of the highest degree of correlation as a recognized output on the basis of the degrees of correlation evaluated by said comparator means, and k. control circuit means which generates signals for controlling the respective circuits.

Claim 7

Character recognition apparatus which comprises a. a photoelectric converter which periodically scans an unknown input character in successive scanning periods to convert it into an electric signal, b. a quantizing circuit connected to said photoelectric converter which quantizes said electric signal into two values in response to detected signal levels, c. a gate circuit connected to said quantizing circuit which opens and closes a circuit providing a clock signal in response to the output signal levels of said quantizing circuit, d. a counter connected to said gate circuit for counting the outputs of said gate circuit during each scanning period, e. a first buffer memory connected to said counter which stores an output of said counter in the form of a projection pattern representative of a peripheral distribution, f. A Fourier transform unit connected to receive an amplitude spectrum from said buffer memory, g. a buffer spectrum memory which stores an output of said Fourier transform unit, h. main memory means for storing amplitude spectra corresponding to a number of standard characters i. comparator means for calculating the degree of correlation between the amplitude spectrum from said main memory and the amplitude spectrum of said buffer spectrum memory, j. output circuit means connected to said comparator means for providing the standard character of the highest degree of correlation as a recognized output on the basis of the degrees of correlation evaluated by said comparator means, and k. control circuit means which generates signals for controlling the respective circuits.

Claim 8

Character recognition apparatus according to claim 5, wherein a. said buffer spectrum memory comprises first and second memory parts which stOre the vertical and horizontal amplitude spectrum patterns of said unknown input character, b. said comparator being additionally provided with a memory circuit which stores a plurality of standard characters of higher degrees of correlation, and c. the comparisons for all said standard characters are first conducted as to one of the horizontal and vertical amplitude spectra, to thereby select a plurality of standard characters of higher degrees of correlation, and the comparisons for only the selected standard characters and subsequently conducted as to the other amplitude spectrum.