Character recognition method and system with strobe control

Claim 2

In a character recognition method wherein a character to be read is scanned along a plurality of scan paths by a corresponding plurality of sensors, each of which sensors is responsive to and produces output conditions identifying the presence or absence of a character segment in its corresponding scan path and the plurality of simultaneously occurring sensor output conditions defining a set of conditions, each occurrence of a change in the output condition of any sensor defining a further said set of conditions and further there is defined, for each character, a prescribeD sequence of states respectively corresponding to at least selected ones of said sets of output conditions as successively defined in scanning that character, each said prescribed sequence of states uniquely identifying the respectively corresponding character as a character of the class, the improvement comprising: scanning a character with said plurality of sensors, responding to a change in a sensor output condition, wherein the resulting set of conditions includes at least one sensor output condition identifying the presence of a character segment in the corresponding scan path, to produce a condition change signal, producing a strobe signal a predetermined time delay following each occurrence of a condition change signal, said time delay being less than the shortest time duration of any set of output conditions produced in scanning any character of the class, responding to the output conditions of said plurality of sensors produced in scanning a character concurrently with each said strobe signal and in accordance with said selected sets of output conditions, to define corresponding states, and processing each successive state thus defined in scanning a character in accordance with the prescribed sequences of states for uniquely identifying the scanned character as one of the characters of the class to be recognized.

Claim 3

In a character recognition method wherein a character to be read is scanned along a plurality of scan paths by a corresponding plurality of sensors, each of which sensors is responsive to and produces output conditions identifying the presence or absence of a character segment in its corresponding scan path and the plurality of simultaneously occurring sensor output conditions defining a set of conditions, each occurrence of a change in the output condition of any sensor defining a further said set of conditions and further there is defined, for each character, a prescribeD sequence of states respectively corresponding to at least selected ones of said sets of output conditions as successively defined in scanning that character, each said prescribed sequence of states uniquely identifying the respectively corresponding character as a character of the class, the improvement comprising: scanning a character with said plurality of sensors, responding to a change in a sensor output condition, wherein the resulting set of conditions includes at least one sensor output condition identifying the presence of a character segment in the corresponding scan path, to produce a condition change signal, producing a strobe signal a predetermined time delay following each occurrence of a condition change signal, said time delay being less than the shortest time duration of any set of output conditions produced in scanning any character of the class, responding to the output conditions of said plurality of sensors produced in scanning a character concurrently with each said strobe signal and in accordance with said selected sets of output conditions, to define corresponding states, and processing each successive state thus defined in scanning a character in accordance with the prescribed sequences of states for uniquely identifying the scanned character as one of the characters of the class to be recognized.

Claim 4

In a character recognition method wherein a character to be read is scanned along a plurality of scan paths by a corresponding plurality of sensors, each of which sensors is responsive to and produces output conditions identifying the presence or absence of a character segment in its corresponding scan path and the plurality of simultaneously occurring sensor output conditions defining a set of conditions, each occurrence of a change in the output condition of any sensor defining a further said set of conditions and further there is defined, for each character, a prescribeD sequence of states respectively corresponding to at least selected ones of said sets of output conditions as successively defined in scanning that character, each said prescribed sequence of states uniquely identifying the respectively corresponding character as a character of the class, the improvement comprising: scanning a character with said plurality of sensors, responding to a change in a sensor output condition, wherein the resulting set of conditions includes at least one sensor output condition identifying the presence of a character segment in the corresponding scan path, to produce a condition change signal, producing a strobe signal a predetermined time delay following each occurrence of a condition change signal, said time delay being less than the shortest time duration of any set of output conditions produced in scanning any character of the class, responding to the output conditions of said plurality of sensors produced in scanning a character concurrently with each said strobe signal and in accordance with said selected sets of output conditions, to define corresponding states, and processing each successive state thus defined in scanning a character in accordance with the prescribed sequences of states for uniquely identifying the scanned character as one of the characters of the class to be recognized.

Claim 5

An improved method of character recognition as recited in claim 1 wherein certain sensor output conditions of said selected sets are treated as ''''don''t care'''' conditions.

Claim 6

An improved method of character recognition as recited in claim 1 further comprising: defining a space state in response to the set of output conditions of said plurality of sensors identifying the absence of character segments in all of the scan paths, and responding to a space state to inhibit generation of a strobe signal.

Claim 7

An improved method of character recognition as recited in claim 1, further comprising: responding only to selected output conditions of said plurality of sensors for producing condition change signals, and selecting sets of conditions for defining corresponding states of the prescribed sequences in accordance with each such set including at least one of the output conditions of said plurality of sensors selected for producing condition change signals.

Claim 8

An improved method of character recognition as recited in claim 1 further comprising: selecting a time delay of said strobe signal in accordance with the speed of scan and the width of a character segment lying transverse to the scan path, to effect generation of the strobe signal when the sensors are positioned, on the average, midway of the width of such transverse character segments.

Claim 9

An improved method of character recognition as recited in claim 1 further comprising: recognizing the initiation of each successive set of output conditions produced in scanning a character by responding to the change in output condition of a sensor of said plurality thereof first effecting such a change, responding to the output conditions of said plurality of sensors a predetermined time interval following each said first sensor output condition change initiating each of said successive sets of conditions and in accordance with said selected sets of output conditions, to define corresponding states, and processing each successive state thus defined in scanning a character in accordance with the prescribed sequences of states for uniquely identifying the scanned character as one of the characters of the class to be recognized.

Claim 10

In a method of character recognition for recognizing characters embossed on a medium and utilizing a plurality of aligned electromechanical sensors individually actuatable and normally urged to a first position corresponding to the background of said medium for producing a first output condition and moved to a second position in response to engaging the segments of the embossed characters to produce a second outpuT condition, and wherein logic means respond to at least selected sets of said output conditions to define corresponding states and further logic means establish prescribed sequences of states uniquely identifying each character of a class to be recognized and process the succession of states defined by the selected ones of the sets of output conditions produced in the scanning of each character for generating an output identifying the scanned character, the improvement comprising: scanning each character in a given direction of scan with the plurality of sensors aligned transversely to the scan direction for responding to each successive, new combination of character segments presented to the transversely aligned sensors in effecting a scan of a character, and thereby identifying successive sets of output conditions of said sensors for each scanned character, responding to the first occurring change in output condition of any of said sensors resultant from movement thereof from one to the other of said positions in scanning each character for recognizing the initiation of the resulting set of output conditions of said sensors, for each such first occurring change in a sensor output condition and the respectively associated, resulting set of conditions, in succession, and responding, a predetermined time interval following each said first occurring change in output condition, to the respectively associated resulting set of output conditions produced, in succession, in scanning each character to define as to the said selected sets of output conditions, the corresponding succession of states.

Claim 11

In a method of character recognition for recognizing characters embossed on a medium and utilizing a plurality of aligned electromechanical sensors individually actuatable and normally urged to a first position corresponding to the background of said medium for producing a first output condition and moved to a second position in response to engaging the segments of the embossed characters to produce a second outpuT condition, and wherein logic means respond to at least selected sets of said output conditions to define corresponding states and further logic means establish prescribed sequences of states uniquely identifying each character of a class to be recognized and process the succession of states defined by the selected ones of the sets of output conditions produced in the scanning of each character for generating an output identifying the scanned character, the improvement comprising: scanning each character in a given direction of scan with the plurality of sensors aligned transversely to the scan direction for responding to each successive, new combination of character segments presented to the transversely aligned sensors in effecting a scan of a character, and thereby identifying successive sets of output conditions of said sensors for each scanned character, responding to the first occurring change in output condition of any of said sensors resultant from movement thereof from one to the other of said positions in scanning each character for recognizing the initiation of the resulting set of output conditions of said sensors, for each such first occurring change in a sensor output condition and the respectively associated, resulting set of conditions, in succession, and responding, a predetermined time interval following each said first occurring change in output condition, to the respectively associated resulting set of output conditions produced, in succession, in scanning each character to define as to the said selected sets of output conditions, the corresponding succession of states.

Claim 12

The method of character recognition as recited in claim 7 further comprising selecting the predetermined time interval in accordance with the speed of scan of said sensors relative to said characters and the minimum width of any character segment lying transverse to the scan path, to enable response to the output conditions of said plurality of sensors when said sensors are, on the average, positioned midway of the width of the character segment.

Claim 13

The method of character recognition as recited in claim 7 wherein said sensors normally engage the surface of the medium from which the embossed characters are raised and are deflected upon engaging the raised segments of each character, each such segment of the character lying transverse to the direction of scan being of finite width, further comprising the steps of: responding to the first occurring change in output condition of the one of said plurality of sensors first moving between positions in response to scanning either the leading or trailing edge of an embossed character segment in its scan path and which change identifies the initiation of a resulting, successive set of conditions, and selecting a time interval such that all of said sensors which are moved to the second position by engaging a transverse segment are located, on the average, midway of the width of the transverse embossed character segment in their respective scan paths and those which are moved to the first position are engaging the background of the medium.

Claim 14

In a character recognition system wherein a character to be read is scanned along a plurality of scan paths by a corresponding plurality of sensors, each of which sensors is responsive to and produces output conditions identifying the presence or absence of a character segment in its corresponding scan path, and wherein a change in the output condition of any sensor defines a new set of output conditions of said plurality of sensors and there furthermore is provided means responsive to at least selected sets of output conditions for defining corresponding states and logic recognition means establishing a prescribed sequence of states uniquely identifying each character of a class to be recognized, said logic recognition means processing the successive states defined by said state defining means during scanning of a character in accordance with said prescribed sequences of states for idenTifying the scanned character, the improvement comprising: means responsive to a change in the output condition of one of said plurality of sensors wherein the resulting, new set of output conditions includes at least one sensor output condition identifying the presence of a character segment in the scan path thereof, to produce a condition change signal, delay means responsive to said condition change signal to produce a strobe signal a predetermined time interval following each occurrence of a condition change signal, defining a further said set of conditions, and said state defining means is normally disabled and is enabled by each said strobe signal to respond to said sets of output conditions.

Claim 15

In a character recognition system wherein a character to be read is scanned along a plurality of scan paths by a corresponding plurality of sensors, each of which sensors is responsive to and produces output conditions identifying the presence or absence of a character segment in its corresponding scan path, and wherein a change in the output condition of any sensor defines a new set of output conditions of said plurality of sensors and there furthermore is provided means responsive to at least selected sets of output conditions for defining corresponding states and logic recognition means establishing a prescribed sequence of states uniquely identifying each character of a class to be recognized, said logic recognition means processing the successive states defined by said state defining means during scanning of a character in accordance with said prescribed sequences of states for idenTifying the scanned character, the improvement comprising: means responsive to a change in the output condition of one of said plurality of sensors wherein the resulting, new set of output conditions includes at least one sensor output condition identifying the presence of a character segment in the scan path thereof, to produce a condition change signal, delay means responsive to said condition change signal to produce a strobe signal a predetermined time interval following each occurrence of a condition change signal, defining a further said set of conditions, and said state defining means is normally disabled and is enabled by each said strobe signal to respond to said sets of output conditions.

Claim 16

The improvement in a character recognition system as recited in claim 10 wherein: said state defining means defines a space state in response to the set of output conditions of said plurality of sensors identifying the absence of character segments in all of the scan paths, and said strobe signal producing means is inhibited from generating a strobe signal by each space state output of said space state defining means.

Claim 17

The improvement in a character recognition system as recited in claim 10 wherein said means for producing a condition change signal comprises: means respectively associated with the outputs of said sensors for producing a pulse of short duration in response to a change in at least selected ones of said output conditions thereof, and gate means responsive to the outputs of said pulse producing means for producing a condition change signal in response to the first such pulse from any of said pulse producing means for each successive set of output conditions.

Claim 18

The improvement in a character recognition system as recited in claim 12 wherein said means for producing short duration pulses comprise differentiators.

Claim 19

The improvement in a character recognition system as recited in claim 13 wherein said time delay means establishes a time interval of a duration related to the speed of relative movement of said sensors and said characters, as the latter scan said characters, and to the width of the character segments lying generally transverse to the direction of motion such that said strobe signal is generated when said plurality of sensors is scanning, on the average, the midposition of each such transverse character segment with respect to its width.

Claim 20

In a character recognition system wherein a character to be read is scanned along a plurality of scan paths by a corresponding plurality of sensors, each of which sensors is responsive to and produces output conditions identifying the presence or absence of a character segment in its corresponding scan path, and wherein a change in the output condition of any sensor defines a new set of output conditions of said plurality of sensors, the improvement comprising in combination: means responsive to a change in the output condition of one of said plurality of sensors wherein the resulting, new set of output conditions includes at least one sensor output condition identifying the presence of a character segment in the scan path thereof, to produce a condition change signal, means responsive to said condition change signal to produce a strobe signal a predetermined time delay following each occurrence of a condition change signal, and means responsive to the output conditions of said plurality of sensors and to the strobe signals for defining states corresponding to at least selected sets of said output conditions of said sensors produced at the times of the strobe signals, and logic recognition means establishing a prescribed sequence of states uniquely identifying each character of a class to be recognized, said logic recognition means being responsive to said state defining means for processing the states, as successively defined by said state defining means during scanning of a character, in accordance with said prescribed sequences of states for idenTifying the scanned character.

Claim 21

In a character recognition system wherein a character to be read is scanned along a plurality of scan paths by a corresponding plurality of sensors, each of which sensors is responsive to and produces output conditions identifying the presence or absence of a character segment in its corresponding scan path, and wherein a change in the output condition of any sensor defines a new set of output conditions of said plurality of sensors, the improvement comprising in combination: means responsive to a change in the output condition of one of said plurality of sensors wherein the resulting, new set of output conditions includes at least one sensor output condition identifying the presence of a character segment in the scan path thereof, to produce a condition change signal, means responsive to said condition change signal to produce a strobe signal a predetermined time delay following each occurrence of a condition change signal, and means responsive to the output conditions of said plurality of sensors and to the strobe signals for defining states corresponding to at least selected sets of said output conditions of said sensors produced at the times of the strobe signals, and logic recognition means establishing a prescribed sequence of states uniquely identifying each character of a class to be recognized, said logic recognition means being responsive to said state defining means for processing the states, as successively defined by said state defining means during scanning of a character, in accordance with said prescribed sequences of states for idenTifying the scanned character.