Abstract Apparatus for assessting the quality of printed characters on a record has a document support arranged beneath a scanning head. The scanning head has a lens arranged to oscillate in a direction parallel to the vertical axis of characters printed on the document. The lens is arranged to focus a character to be evaluated on to a set of photoelectic strips arranged side-byside in a direction perpendicular to the oscillatory movement of the lens, so that a character image is scanned in vertical strips. The lens moving arrangement also has a timing pulse generator so that the character scan is broken into notional zones which, in conjunction with the orientation of the photoelectric strips enables a matrix representation of the recorded character to be generated. The separate output signals from the photoelectric strips are passed to shifting registers whose stages are connected to a storage matrix capable of selecting an idealised character form to be compared with the scanned character. The comparison is carried out over a number of scanning cycles while the position of the document carrying the character is changed and an indication is provided of the least deviation of the scanned character from the idealised character form during the change.
Apparatus for matching characteristics of a printed character with a preferred standard form of that character to evaluate the suitability of the printed character for use in a character recognition system, including scanning means arranged to scan in a single operation a predetermined planar area, the area being of greater extent than is required to contain the character; means for supporting a document carrying the printed character in a position in which the character is in the plane of but not lying wholly within said area; means operable to move the document along a path such that the character lies within the area throughout at least a part of the path, the movement permitting scanning of the entire character, the scanning being arranged during movement of the document repeatedly to scan the area in a succession of scanning operations to derive a first signal representing for each operation those parts of the character scanned during that operatIon; a character store containing representations of preferred standard forms of a plurality of characters; means operable to select from the store the standard form representation of the printed character to derive a second signal; comparing means responsive to said first and said second signals to generate an output whose magnitude is proportional for each complete scanning operation to the degree of divergence of the scanned portion of the printed character from the standard form; a signal storage device responsive to the output from each successive scanning operation such that a stored signal is changed only if the magnitude of the current output is less than the least of the outputs from preceding scanning operations, whereby the stored signal at the end of the succession of scanning operations has a magnitude proportional to the least deviation of the printed character from the standard form during the succession; and means responsive to the stored signal to produce a visual indication of said least deviation under the best possible match conditions occurring during the succession.
Claim 2
Dependent Claim
329 words
Apparatus for matching characteristics of a printed character with a preferred standard form of that character to evaluate the suitability of the printed character for use in a character recognition system, including scanning means arranged to scan in a single operation a predetermined planar area, the area being of greater extent than is required to contain the character; means for supporting a document carrying the printed character in a position in which the character is in the plane of but not lying wholly within said area; means operable to move the document along a path such that the character lies within the area throughout at least a part of the path, the movement permitting scanning of the entire character, the scanning being arranged during movement of the document repeatedly to scan the area in a succession of scanning operations to derive a first signal representing for each operation those parts of the character scanned during that operatIon; a character store containing representations of preferred standard forms of a plurality of characters; means operable to select from the store the standard form representation of the printed character to derive a second signal; comparing means responsive to said first and said second signals to generate an output whose magnitude is proportional for each complete scanning operation to the degree of divergence of the scanned portion of the printed character from the standard form; a signal storage device responsive to the output from each successive scanning operation such that a stored signal is changed only if the magnitude of the current output is less than the least of the outputs from preceding scanning operations, whereby the stored signal at the end of the succession of scanning operations has a magnitude proportional to the least deviation of the printed character from the standard form during the succession; and means responsive to the stored signal to produce a visual indication of said least deviation under the best possible match conditions occurring during the succession.