Character recognition method and system with leading trailing edge control

Claim 5

A method of character recognition as recited in claim 1, further comprising: defining an index condition comprising the set of output conditions corresponding to the absence of any character segment in any scan path, and responding to the index condition to distinguish between successive characters being scanned.

Claim 6

A method of character recognition as recited in claim 1, further comprising: defining an index condition comprising the set of output conditions corresponding to the absence of any character segment in any scan path, and responding to the index condition to identify completion of scanning of a character.

Claim 7

A method of character recognition as recited in claim 3, further comprising: for each character having no vertical segment at the trailing edge thereof, selecting as the trailing edge set of output conditions, the output conditions of said intermediate scan paths identifying the absence of character segments therein, and the index condition.

Claim 8

A method of character recognition as recited in claim 1, wherein the class of characters is defined by a seven segment, generally rectangular font of upper and lower left vertical segments, upper and lower right vertical segments, and said upper, middle and lower horizontal segments.

Claim 11

A method of character recognition as recited in claim 6, further comprising: selecting said sets of output conditions for identifying the central portion of a character to include only those sets for which no vertical segment is scanned in the intermediate scan paths.

Claim 12

A method of character recognition as recited in claim 6, further comprising: responding to the decoded output condition identifying the leading edge of a character being scanned thereby to enable the decoding of said output conditions in accordance with the selected sets thereof corresponding to the central portions and trailing edges of the characters being scanned.

Claim 13

A method of character recognition as recited in claim 6, further comprising: responding to the set of output conditions for all of said scan paths identifying the absence of any character segment in any scan path to define an index condition, and inhibiting the decoding of any of said output conditions during the index condition.

Claim 14

A method of character recognition as recited in claim 6, further comprising: storing the output conditions for the intermediate scan paths corresponding to scanning of the leading edge of a scanned character, prior to decoding thereof, and enabling the decoding of the thus stored output conditions for the intermediate scan paths, only in response to the subsequent set of output conditions for the intermediate scan paths corresponding to the absence of any vertical segment therein.

Claim 17

A character recognition system for recognizing characters of a class having a font style of substantially straight line segments including upper and lower vertical segment positions and upper, middle, and lower horizontal segment positions, wherein each character to be recognized is scanned in a plurality of horizontal scan paths including at least two scan paths aligned with said horizontal segment positions and two scan paths respectively intermediate the upper and middle, and the middle and lower horizontal segment positions to produce output conditions identifying the presence or absence of a character segment in each of the scan paths, each differing combination of simultaneously occurring scan path output conditions defining a respectively corresponding set of output conditions and wherein each character of the class includes at least one vertical segment at a commonly disposed vertical position thereof defining the leading edge of each character and determining thereby the direction of scan of the characters, the leading edge thereby being scanned in at least one of said intermediate paths, comprising: means for scanning each character to be recognized in the predetermined direction to produce a succession of sets of output conditions of said scan paths in accordance with the output condition of any scan path changing during the scanning of the character, decoding means responsive to the output conditions of the intermediate scan paths in each of said succession of sets for decoding said output conditions in accordance with selected sets thereof corresponding to leading and trailing edges of the characters of the class, and producing outputs identifying the sets of output conditions decoded thereby in response to the output conditions produced in scanning thE leading and trailing edges, respectively, of each character, further decoding means responsive to the output conditions of at least two of the upper, middle, and lower scan paths in each of said succession of sets for decoding said output conditions in accordance with selected sets thereof corresponding to the central portion of each character of the class, and producing an output identifying the set of output conditions decoded thereby in response to the output conditions produced in scanning the central portion of each character, and logic recognition means defining prescribed sequences of leading edge, central, and trailing edge selected sets of conditions uniquely identifying each character of the class, and responsive to the outputs of said decoding means in scanning of each unknown character to identify the character in accordance with the sets of conditions identified by the decoded outputs of said decoding means and corresponding to one of said prescribed sequences.

Claim 18

A character recognition system for recognizing characters of a class having a font style of substantially straight line segments including upper and lower vertical segment positions and upper, middle, and lower horizontal segment positions, wherein each character to be recognized is scanned in a plurality of horizontal scan paths including at least two scan paths aligned with said horizontal segment positions and two scan paths respectively intermediate the upper and middle, and the middle and lower horizontal segment positions to produce output conditions identifying the presence or absence of a character segment in each of the scan paths, each differing combination of simultaneously occurring scan path output conditions defining a respectively corresponding set of output conditions and wherein each character of the class includes at least one vertical segment at a commonly disposed vertical position thereof defining the leading edge of each character and determining thereby the direction of scan of the characters, the leading edge thereby being scanned in at least one of said intermediate paths, comprising: means for scanning each character to be recognized in the predetermined direction to produce a succession of sets of output conditions of said scan paths in accordance with the output condition of any scan path changing during the scanning of the character, decoding means responsive to the output conditions of the intermediate scan paths in each of said succession of sets for decoding said output conditions in accordance with selected sets thereof corresponding to leading and trailing edges of the characters of the class, and producing outputs identifying the sets of output conditions decoded thereby in response to the output conditions produced in scanning thE leading and trailing edges, respectively, of each character, further decoding means responsive to the output conditions of at least two of the upper, middle, and lower scan paths in each of said succession of sets for decoding said output conditions in accordance with selected sets thereof corresponding to the central portion of each character of the class, and producing an output identifying the set of output conditions decoded thereby in response to the output conditions produced in scanning the central portion of each character, and logic recognition means defining prescribed sequences of leading edge, central, and trailing edge selected sets of conditions uniquely identifying each character of the class, and responsive to the outputs of said decoding means in scanning of each unknown character to identify the character in accordance with the sets of conditions identified by the decoded outputs of said decoding means and corresponding to one of said prescribed sequences.

Claim 19

A character recognition system as recited in claim 12, wherein said further decoding means for identifying the central portion of a character is responsive only to those sets of output conditions corresponding to the absence of a vertical segment in the intermediate scan paths.

Claim 20

A character recognition system as recited in claim 12, further comprising: means responsive to the output of said decoding means identifying a decoded selected set of conditions corresponding to the leading edge of a character being scanned, for producing an enabling signal, and said decoding means for the central and trailing edge sets of conditions being normally disabled, and being responsive to the enabling signal output of said enabling signal means for producing outputs identifying the decoded, selected sets of conditions for the leading and trailing edges of a character being scanned.

Claim 21

A character recognition system as recited in claim 14, further comprising: indexing means responsive to the output conditions for all of said scan paths and operative in response to all of said output conditions corresponding to the absence of any character segment in all of said corresponding scan paths to produce an output identifying an index condition, and said decoding means for the leading edge set of conditions being disabled in response to the index condition output of said indexing means from decoding the output conditions of said intermediate scan paths.

Claim 22

A character recognition system as recited in claim 12, wherein said leading/trailing edge decoding means further comprises: means for storing the output conditions derived for the intermediate scan paths in scanning of a character, said decoding means for said leading and said trailing edge sets of condition being responsive to said stored output conditions for decoding thereof in producing said outputs identifying the leading and trailing edges, respectively, of each character, and means responsive to the output conditions of the intermediate scan paths for disabling said leading and trailing edge decoding means when said intermediate scan path output conditions identify the presence of a vertical segment in either of said intermediate scan paths and for enabling said leading and trailing edge decoding means when said intermediate scan path output conditions correspond to the absence of a vertical segment in both of said intermediate scan paths.

Claim 23

A character recognition system for recognizing characters of a class having a font style of substantially straight line segments including upper and lower vertical segment positions and upper, middle, and lower horizontal segment positions, wherein each character to be recognized is scanned in a plurality of horizontal scan paths including at least two scan paths aligned with said horizontal segment positions and two scan paths respectively intermediate the upper and middle, and the middle and lower horizontal segment positions to produce output conditions identifying The presence or absence of a character segment in each of the scan paths, each differing combination of simultaneously occurring scan path output conditions defining a respectively corresponding set of output conditions and wherein each character of the class includes at least one vertical segment at a commonly disposed vertical portion thereof defining the leading edge of each character and determining thereby the direction of scan of the characters, the leading edge thereby being scanned in at least one of said intermediate paths, comprising: leading/trailing edge output condition storage means for storing the output conditions of the intermediate scan paths in scanning of a character, leading/trailing edge decoding means responsive to the stored output conditions of the intermediate scan paths of said storing means for decoding thereof in accordance with sets of said intermediate scan path output conditions selected for identifying the leading and trailing edges of the characters of the class and producing outputs identifying the sets thus decoded in scanning the leading and trailing edges of each character, leading edge storage means for storing the output of said leading/trailing edge decoding means identifying the decoded and selected set of conditions for the leading edge of a character being scanned, control means responsive to the identification of a leading edge selected set of conditions from said leading edge storage means to produce an enabling signal, input gate means for said leading edge storage means normally enabled to supply the decoded output of said leading/trailing edge decoding means to said leading edge storage means and responsive to the output of said control means to be disabled thereby, said leading edge storage means thereby maintaining the stored and decoded selected set of conditions derived in scanning the leading edge of a character throughout the duration of scanning of that character, central portion output condition storage means for storing the output conditions of the scan paths for the upper, middle and lower horizontal segments, gate means for said central portion storage means responsive to said enabling signal output of said control means for being enabled to supply the output conditions derived in scanning a central portion of the character to said central portion output condition storage means for storage therein, central portion decoding means responsive to the stored central portion output conditions in accordance with selected sets thereof and producing an output identifying the decoded selected set of output conditions derived in scanning the central portion of a character, trailing edge gating means enabled by the enabling output of said control means and responsive to the outputs of said leading/trailing edge decoding means corresponding to scanning of a trailing edge of a character to produce an output identifying the decoded selected set of trailing edge conditions for a character being scanned, and logic recognition means defining prescribed sequences of leading edge, central and trailing edge selected sets of conditions uniquely identifying each character of the class, and responsive to the outputs of said leading edge storage means, and said central and said trailing edge decoding means produced in scanning each unknown character, to identify the character in accordance with the decoded, selected sets of conditions identified by the outputs of said decoding means and corresponding to one of said prescribed sequences.

Claim 24

A character recognition system for recognizing characters of a class having a font style of substantially straight line segments including upper and lower vertical segment positions and upper, middle, and lower horizontal segment positions, wherein each character to be recognized is scanned in a plurality of horizontal scan paths including at least two scan paths aligned with said horizontal segment positions and two scan paths respectively intermediate the upper and middle, and the middle and lower horizontal segment positions to produce output conditions identifying The presence or absence of a character segment in each of the scan paths, each differing combination of simultaneously occurring scan path output conditions defining a respectively corresponding set of output conditions and wherein each character of the class includes at least one vertical segment at a commonly disposed vertical portion thereof defining the leading edge of each character and determining thereby the direction of scan of the characters, the leading edge thereby being scanned in at least one of said intermediate paths, comprising: leading/trailing edge output condition storage means for storing the output conditions of the intermediate scan paths in scanning of a character, leading/trailing edge decoding means responsive to the stored output conditions of the intermediate scan paths of said storing means for decoding thereof in accordance with sets of said intermediate scan path output conditions selected for identifying the leading and trailing edges of the characters of the class and producing outputs identifying the sets thus decoded in scanning the leading and trailing edges of each character, leading edge storage means for storing the output of said leading/trailing edge decoding means identifying the decoded and selected set of conditions for the leading edge of a character being scanned, control means responsive to the identification of a leading edge selected set of conditions from said leading edge storage means to produce an enabling signal, input gate means for said leading edge storage means normally enabled to supply the decoded output of said leading/trailing edge decoding means to said leading edge storage means and responsive to the output of said control means to be disabled thereby, said leading edge storage means thereby maintaining the stored and decoded selected set of conditions derived in scanning the leading edge of a character throughout the duration of scanning of that character, central portion output condition storage means for storing the output conditions of the scan paths for the upper, middle and lower horizontal segments, gate means for said central portion storage means responsive to said enabling signal output of said control means for being enabled to supply the output conditions derived in scanning a central portion of the character to said central portion output condition storage means for storage therein, central portion decoding means responsive to the stored central portion output conditions in accordance with selected sets thereof and producing an output identifying the decoded selected set of output conditions derived in scanning the central portion of a character, trailing edge gating means enabled by the enabling output of said control means and responsive to the outputs of said leading/trailing edge decoding means corresponding to scanning of a trailing edge of a character to produce an output identifying the decoded selected set of trailing edge conditions for a character being scanned, and logic recognition means defining prescribed sequences of leading edge, central and trailing edge selected sets of conditions uniquely identifying each character of the class, and responsive to the outputs of said leading edge storage means, and said central and said trailing edge decoding means produced in scanning each unknown character, to identify the character in accordance with the decoded, selected sets of conditions identified by the outputs of said decoding means and corresponding to one of said prescribed sequences.

Claim 25

A character recognition system as recited in claim 17, further comprising: means responsive to the enabling output of said control means upon the identification of a decoded selected set of leading edge conditions, for clearing said leading/trailing edge storage means in preparation for storing of the output conditions of said intermediate scan paths resultant from scanning of a trailing edge of a character.

Claim 26

A character recognition system aS recited in claim 17, further comprising: inhibit means responsive to the output conditions of the intermediate scan paths for producing an inhibit signal when said output conditions correspond to the presence of a vertical segment in either of said intermediate scan paths, and to produce an enable output when said output conditions correspond to the absence of a vertical segment in both of said intermediate scan paths, and said leading/trailing edge decoding means further being responsive to the inhibit and enable outputs of said inhibit means for being correspondingly inhibited from, and enabled for, decoding of the stored output conditions of said leading/trailing edge storage means.

Claim 27

A character recognition system as recited in claim 17, further comprising: indexing means responsive to the output conditions for all of said scan paths and operative in response to all of said output conditions corresponding to the absence of any character segment in all of said corresponding scan paths to produce an output identifying an index condition, and input gating means for supplying and leading/trailing edge output conditions to said storage means therefor, said input gating means being disabled in response to the index condition output of said indexing means for inhibiting gating of said output conditions to said storage means.