US3755780A
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US
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Method for recognizing characters
Assignee: PATTERN ANALYSIS AND RECOGNITION
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Filing: 1971-06-28
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Granted: 1973-08-28
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Expires: 1991-06-28
Abstract
Abstract A method for recognizing a digitized character. The shape of the character is represented by the number, positions and shapes of alternating contour convexities, as viewed from two sides of the character. The number and positions of the convexities define the sort group of the character, there being nine sort groups in the systems described. Each sort group has associated with it a separate linear discriminant logic test for every pair of characters which share the sort group. Depending on the sort group of the character to be recognized, the associated pairwise discriminant tests are performed, and the character class which passes a specified number of the tests is identified as the class of the character to be recognized.
Inventors
- 👤 J Sammon
- 👤 J Sanders
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:02
CPC Classifications
G; G06; G06V; G06V10/00; G06V10/20; G06V10/32; G06V10/40; G06V10/46
Claims Analysis
Total Claims: 172
Claim 1
Independent Claim
190 words
A method to be practiced on a machine for identifying a character on a document as being one of a pre-determined set comprising the steps of: 1. using apparatus to scan said document in the area of the charac-ter to generate electrical signals corresponding to the image of the character on the document, 2. using apparatus responsive to the electrical signals generated in step (1) to generate a sequence of signals composed of two different signal types, saId sequence corresponding to a binary raster representation of said character, 3. using apparatus to convert said binary raster representation to a set of numbers representative of respective features of said binary raster representation, 4. using apparatus to perform a plurality of tests on said set of numbers, each of said tests serving to discriminate between a respective pair of characters in said predetermined set for determining if one of the characters of the pair is more likely to be the character to be identified than the other character of the pair, and 5. using apparatus to identify the character in accordance with the results of the pairwise tests performed in step (4).
Claim 2
Independent Claim
190 words
A method to be practiced on a machine for identifying a character on a document as being one of a pre-determined set comprising the steps of: 1. using apparatus to scan said document in the area of the charac-ter to generate electrical signals corresponding to the image of the character on the document, 2. using apparatus responsive to the electrical signals generated in step (1) to generate a sequence of signals composed of two different signal types, saId sequence corresponding to a binary raster representation of said character, 3. using apparatus to convert said binary raster representation to a set of numbers representative of respective features of said binary raster representation, 4. using apparatus to perform a plurality of tests on said set of numbers, each of said tests serving to discriminate between a respective pair of characters in said predetermined set for determining if one of the characters of the pair is more likely to be the character to be identified than the other character of the pair, and 5. using apparatus to identify the character in accordance with the results of the pairwise tests performed in step (4).
Claim 3
Dependent Claim
34 words
using apparatus responsive to the electrical signals generated in step (1) to generate a sequence of signals composed of two different signal types, saId sequence corresponding to a binary raster representation of said character,
Claim 4
Dependent Claim
34 words
using apparatus responsive to the electrical signals generated in step (1) to generate a sequence of signals composed of two different signal types, saId sequence corresponding to a binary raster representation of said character,
Claim 5
Dependent Claim
70 words
A method in accordance with claim 1 wherein in step (5) the character is identified as a particular character only if during the performance of pairwise tests in step (4) the particular character was determined to be the more likely identity of the character to be identified in a predetermined number of the tests in each of which the particular character was one of the two in the test pair.
Claim 6
Dependent Claim
34 words
using apparatus responsive to the electrical signals generated in step (1) to generate a sequence of signals composed of two different signal types, said sequence corresponding to a binAry raster representation of said character,
Claim 7
Dependent Claim
34 words
using apparatus responsive to the electrical signals generated in step (1) to generate a sequence of signals composed of two different signal types, said sequence corresponding to a binAry raster representation of said character,
Claim 8
Dependent Claim
34 words
using apparatus to perform a plurality of tests on said vector, each of said tests serving to discriminate between a respective pair of characters in said predetermined set relative to said digitized character, and
Claim 9
Dependent Claim
34 words
using apparatus to perform a plurality of tests on said vector, each of said tests serving to discriminate between a respective pair of characters in said predetermined set relative to said digitized character, and
Claim 10
Dependent Claim
21 words
controlling said apparatus to compute the features of said set for each of a plurality of representative characters in said group,
Claim 11
Dependent Claim
21 words
controlling said apparatus to compute the features of said set for each of a plurality of representative characters in said group,
Claim 12
Dependent Claim
99 words
controlling said machine to terminate the performance of pairwise tests in step (1) when either a. each of said character classes has been determined not to have a greater probability than the other character class in at least one of the pairwise tests performed in which said each character class was one of the classes in the test, or b. one of said character classes has been determined to have a greater probability then the other character class in all of the pairwise tests in which said one character class is one of the classes in the test, and
Claim 13
Dependent Claim
99 words
controlling said machine to terminate the performance of pairwise tests in step (1) when either a. each of said character classes has been determined not to have a greater probability than the other character class in at least one of the pairwise tests performed in which said each character class was one of the classes in the test, or b. one of said character classes has been determined to have a greater probability then the other character class in all of the pairwise tests in which said one character class is one of the classes in the test, and
Claim 14
Dependent Claim
92 words
controlling said machine to select one of a plurality of groups of machine tests to be performed on said character, each group of tests being associated with a sub-set of characters which are known to have a respective set of features in common and serving to discriminate between such characters, the respective set of features associated with each group of tests being a set of character contour features as seen looking from outside the character, the selected group being that whose associated set of features is represented by said vector elements, and
Claim 15
Dependent Claim
92 words
controlling said machine to select one of a plurality of groups of machine tests to be performed on said character, each group of tests being associated with a sub-set of characters which are known to have a respective set of features in common and serving to discriminate between such characters, the respective set of features associated with each group of tests being a set of character contour features as seen looking from outside the character, the selected group being that whose associated set of features is represented by said vector elements, and
Claim 16
Dependent Claim
23 words
controlling said machine to perform pairwise discriminant tests on said vector for recognizing said digitized character based on the results of the tests.
Claim 17
Dependent Claim
23 words
controlling said machine to perform pairwise discriminant tests on said vector for recognizing said digitized character based on the results of the tests.
Claim 18
Dependent Claim
18 words
performing the machine tests in the selected group and recognizing the character in accordance with the tests results.
Claim 19
Dependent Claim
18 words
performing the machine tests in the selected group and recognizing the character in accordance with the tests results.
Claim 20
Dependent Claim
41 words
controlling said machine to indicate a rejection of said character to be recognized when condition (a) is satisfied, and to indicate identification of said character to be recognized as being contained in said one character class when condition (b) is satisfied.
Claim 21
Dependent Claim
41 words
controlling said machine to indicate a rejection of said character to be recognized when condition (a) is satisfied, and to indicate identification of said character to be recognized as being contained in said one character class when condition (b) is satisfied.
Claim 22
Dependent Claim
44 words
controlling said apparatus to compute a set of discriminants and associated threshold values based on the sets of features computed in step (2) for said representative characters, each of said discriminants and associated threshold values being operative for discriminating between two character classes, and
Claim 23
Dependent Claim
44 words
controlling said apparatus to compute a set of discriminants and associated threshold values based on the sets of features computed in step (2) for said representative characters, each of said discriminants and associated threshold values being operative for discriminating between two character classes, and
Claim 24
Dependent Claim
20 words
using apparatus to recognize the digitized character based upon the results of the pairwise character tests performed in step (2).
Claim 25
Dependent Claim
20 words
using apparatus to recognize the digitized character based upon the results of the pairwise character tests performed in step (2).
Claim 26
Dependent Claim
39 words
using apparatus to convert said binary raster representation to a set of numbers representative of features which include the numbers, shapes and locations of alternating bumps of opposite convexities as seen looking from outside said binary raster representation, and
Claim 27
Dependent Claim
39 words
using apparatus to convert said binary raster representation to a set of numbers representative of features which include the numbers, shapes and locations of alternating bumps of opposite convexities as seen looking from outside said binary raster representation, and
Claim 28
Dependent Claim
22 words
using apparatus to convert said binary raster representation to a set of numbers representative of respective features of said binary raster representation,
Claim 29
Dependent Claim
22 words
using apparatus to convert said binary raster representation to a set of numbers representative of respective features of said binary raster representation,
Claim 30
Dependent Claim
34 words
A method in accordance with claim 2 wherein said predetermined number is equal to the number of the tests in each of which the particular character was one of two in the test pair.
Claim 31
Dependent Claim
58 words
using apparatus to perform a plurality of tests on said set of numbers, each of said tests serving to discriminate between a respective pair of characters in said predetermined set for determining if one of the characters of the pair is more likely to be the character to be identified than the other character of the pair, and
Claim 32
Dependent Claim
58 words
using apparatus to perform a plurality of tests on said set of numbers, each of said tests serving to discriminate between a respective pair of characters in said predetermined set for determining if one of the characters of the pair is more likely to be the character to be identified than the other character of the pair, and
Claim 33
Dependent Claim
18 words
using apparatus to perform tests on said set of numbers to determine the identity of the scanned character.
Claim 34
Dependent Claim
18 words
using apparatus to perform tests on said set of numbers to determine the identity of the scanned character.
Claim 35
Dependent Claim
21 words
establishing a sequence in which said set of discriminants should be used by a machine for the recognition of a character.
Claim 36
Dependent Claim
21 words
establishing a sequence in which said set of discriminants should be used by a machine for the recognition of a character.
Claim 37
Dependent Claim
44 words
A method in accordance with claim 3 wherein the features of said binary number representation which are represented by said set of numbers include the numbers, shapes and locations of alternating bumps of opposite convexities as seen looking from at least two different directions.
Claim 38
Dependent Claim
42 words
A method in accordance with claim 1 wherein in step (2) the represented character is operated upon to stretch it in at least one direction such that the length in said one direction of the binary raster representation is of predetermined length.
Claim 39
Dependent Claim
19 words
using apparatus to identify the character in accordance with the results of the pairwise tests performed in step (4).
Claim 40
Dependent Claim
19 words
using apparatus to identify the character in accordance with the results of the pairwise tests performed in step (4).
Claim 41
Dependent Claim
25 words
A method in accordance with claim 5 wherein in step (2) the binary raster representation is operated upon to correct breaks in said one direction.
Claim 42
Dependent Claim
44 words
A method in accordance with claim 1 wherein the features of said binary raster representation which are represented by said set of numbers include the numbers, shapes and locations of alternating bumps of opposite convexities as seen looking from outside said binary raster representation.
Claim 43
Dependent Claim
103 words
A method in accordance with claim 7 wherein the pairwise tests are included in a plurality of groups, the groups being associated with respective numbers of alternating bumps of opposite convexities and the pairwise tests included in the respective groups being those for discriminating between characters whose features correspond to the respective numbers of alternating bumps of opposite convexities, and in step (4) the only pairwise tests which are performed are those in the group for discriminating between characters whose features correspond to the same number of alternating bumps of opposite convexities as the number corresponding to the features determined in step (3).
Claim 44
Dependent Claim
45 words
A method in accordance with claim 8 wherein each of said groups of tests includes a test for discriminating between each possible pair of characters in said predetermined set whose features correspond to the number of alternating bumps of opposite convexities associated with the group.
Claim 45
Dependent Claim
111 words
A method in accordance with claim 9 wherein in step (5) the character is identified as a particular character only if during the performance of pairwise tests in step (4) the particular character was determined to be the more likely identity of the character to be identified in a predetermined number of the tests in each of which the particular character was one of the two in the test pair, and the pairwise tests are performed in step (4) in an order determined by the probabilities of occurrence of the characters to be discriminated to reduce the average number of pairwise tests which otherwise would be performed to identify a character.
Claim 46
Dependent Claim
110 words
A method in accordance with claim 7 wherein the featUres of said binary raster representation which are represented by said set of numbers further include a number which is dependent upon the difference between (a) the sum of numbers proportional to lengths on the two side regions of the binary raster representation which correspond to the absence of parts of the scanned character above a horizontal row positioned in the lower half of the binary raster representation, and (b) a number proportional to a length in the central region of the binary raster representation which corresponds to the absence of a part of the scanned character above said horizontal row.
Claim 47
Dependent Claim
93 words
A method in accordance with claim 7 wherein the features of said binary raster representation which are represented by said set of numbers further include a number which is dependent upon a length in the binary raster representation which corresponds to the absence of a part of the scanned character above a horizontal row positioned in the lower half of the binary raster representation, which length is measured in the vertical direction immediately to the left of the leftmost portion of said horizontal row which corresponds to a part of the scanned character.
Claim 48
Dependent Claim
107 words
A method in accordance with claim 7 wherein the features of said binary raster representation which are represented by said set of numbers further include a number which is dependent upon the difference between (a) a number proportional to a length in the central region of the binary raster representation which corresponds to the absence of a part of the scanned character at the top of the binary raster representation, and (b) the sum of numbers proportional to lengths on the two sides of the binary raster representation which correspond to the absence of parts of the scanned character at the top of the binary raster representation.
Claim 49
Dependent Claim
67 words
A method in accordance with claim 7 wherein the features of said binary raster representation which are represented by said set of numbers further include a number which is dependent upon the average horizontal width between the leftmost and rightmost portions of the binary raster representation which represents parts of the scanned character taken along horizontal rows of the binary raster representation in the bottom portion thereof.
Claim 50
Dependent Claim
85 words
A method in accordance with claim 7 wherein the features of said binary raster representation which are represented by said set of numbers further include a number which is dependent upon the average horizontal width between the leftmost and rightmost portions of the binary raster representation which represents parts of the scanned character taken along horizontal rows of the binary raster representation in the central region thereof, which central region includes less than half of the total number of rows of the binary raster representation.
Claim 51
Dependent Claim
85 words
A method in accordance with claim 7 wherein the features of said binary raster representation which are represented by said set of numbers further include a number which is dependent upon the average horizontal width between the leftmost and rightmost portions of the binary raster representation which represents parts of the scanned character taken along horizontal rows of the binary raster representation in the central region thereof, which central region includes more than half of the total number of rows of the binary raster representation.
Claim 52
Dependent Claim
68 words
A method in accordance with claim 7 wherein the features of said binary raster representation which are represented by said set of numbers further include a number which is dependent upon the total number of continuous line segments represented by said binary raster representation along a group of rows thereof, said group consisting of rows in the central region of the upper half of the binary raster representation.
Claim 53
Dependent Claim
68 words
A method in accordance with claim 7 wherein the features of said binary raster representation which are represented by said set of numbers further include a number which is dependent upon the total number of continuous linE segments represented by said binary raster representation along a group of rows thereof, said group consisting of rows in the central region of the lower half of the binary raster representation.
Claim 54
Dependent Claim
215 words
A method in accordance with claim 7 wherein step (3) includes the sub-steps of: (3a) computing at least two differently directed histograms for said binary raster representation, (3b) computing a pair of difference strings for said binary raster representation by subtracting each element in each of said differently directed histograms from an adjacent element, (3c) changing the values of pairs of successive elements in each of said difference strings to minimize the effects of noise in said binary raster representation, thereby producing edited differently directed difference strings, (3d) deriving a list of magnitude and direction codes for a sequence of straight-line segments for each of the edited differently directed difference strings in accordance with the element values thereof, the direction of each straight-line segment being one of a predetermined relatively small number, (3e) inserting magnitude and direction codes for additional straight-line segments in each of said lists in accordance with the magnitudes and direction codes for the straight-line segments derived in step (3d) to derive a composite list of straight-line segments whose direction codes change in a predetermined order which causes the successive straight-line segments in each list to represent bumps of alternating opposite convexities, and (3f) combining said lists to derive said set of numbers representative of the features of said binary raster representation.
Claim 55
Dependent Claim
65 words
A method in accordance with claim 19 wherein step (3) further includes the sub-step of: (3g) computing each of a group of special feature numbers from said binary raster representation in accordance with a respective formula, said group of special feature numbers being combined with said lists in sub-step (3f) to derive said set of numbers representative of the features of said binary raster representation.
Claim 56
Dependent Claim
119 words
A method in accordance with claim 7 wherein step (3) includes the sub-steps of: (3a) computing at least two differently directed histograms for said binary raster representation, (3b) computing a pair of lists of straight-line segments from respective ones of said differently directed histograms, the straight-line segments in said lists representing bumps of alternating opposite convexities conforming to the contour of said binary raster representation, (3c) computing each of a group of special feature numbers from said binary raster representation in accordance with a respective formula, and (3d) combining the lists computed in step (3b) and the special feature numbers computed in step (3c) to derive said set of numbers representative of the features of said binary raster representation.
Claim 57
Dependent Claim
103 words
A method in accordance with claim 21 wherein the pairwise tests are included in a plurality of groups, the groups being associated with respective numbers of alternating bumps of opposite convexities and the pairwise tests included in the respective groups being those for discriminating between characters whose features correspond to the respective number of alternating bumps of opposite convexities, and in step (4) the only pairwise tests which are performed are those in the group for discriminating between characters whose features correspond to the same number of alternating bumps of opposite convexities as the number corresponding to the features determined in step (3).
Claim 58
Dependent Claim
45 words
A method in accordance with claim 22 wherein each of said groups of tests includes a test for discriminating between each possible pair of characters in said predetermined set whose features correspond to the number of alternating bumps of opposite convexities associated with the gRoup.
Claim 59
Dependent Claim
111 words
A method in accordance with claim 23 wherein in step (5) the character is identified as a particular character only if during the performance of pairwise tests in step (4) the particular character was determined to be the more likely identity of the character to be identified in a predetermined number of the tests in each of which the particular character was one of the two in the test pair, and the pairwise tests are performed in step (4) in an order determined by the probabilities of occurrence of the characters to be discriminated to reduce the average number of pairwise tests which otherwise would be performed to identify a character.
Claim 60
Dependent Claim
36 words
A method in accordance with claim 24 wherein each of the pairwise tests performed in step (4) is the computation of an optimal linear discriminant designed to distinguish between the two characters of the respective pair.
Claim 61
Dependent Claim
70 words
A method in accordance with claim 25 wherein in step (5) the character is identified as a particular character only if during the performance of pairwise tests in step (4) the particular character was determined to be the more likely identity of the character to be identified in a predetermined number of the tests in each of which the particular character was one of the two in the test pair.
Claim 62
Dependent Claim
103 words
A method in accordance with claim 26 wherein the pairwise tests are included in a plurality of groups, the groups being associated with respective numbers of alternating bumps of opposite convexities and the pairwise tests included in the respective groups being those for discriminating between characters whose features correspond to the respective numbers of alternating bumps of opposite convexities, and in step (4) the only pairwise tests which are performed are those in the group for discriminating between characters whose features correspond to the same number of alternating bumps of opposite convexities as the number corresponding to the features determined in step (3).
Claim 63
Dependent Claim
86 words
A method in accordance with claim 8 wherein for a group of pairwise tests the tests are performed in a sequence such that TIJ precedes TRQ if and only if PI > PR for I not = R and PJ > PQ for I R, where Tij represents a test for discriminating between characters i and j, and PK represents the probability of character K being identified from among all of the characters which are scanned and are discriminated by the pairwise tests in said group.
Claim 64
Dependent Claim
70 words
A method in accordance with claim 28 wherein in step (5) the character is identified as a particular character only if during the performance of pairwise tests in step (4) the particular character was determined to be the more likely identity of the character to be identified in a predetermined number of the tests in each of which the particular character was one of the two in the test pair.
Claim 65
Dependent Claim
34 words
A method in accordance with claim 29 wherein said predetermined number is equal to the number of the tests in each of which the particular character was one of two in the test pair.
Claim 66
Dependent Claim
75 words
A method in accordance with claim 28 wherein the data for each pairwise test includes a plurality of weights to be used in computing a respective optimal linear discriminant, threshold values for enabling a character decision to be made after the optimal linear discriminant is computed, and pointer values for indicating the data to be used for the next pairwise test in accordance with the character decision made at the end of the current test.
Claim 67
Dependent Claim
75 words
A method in accordance with claim 8 wherein the data for each pairwise test includes a plurality of weights to be used in computing a respective optimal linear discriminant, threshold values for enabling a character decision to be made after the optimal linear discriminant is computed, and pointer values for indicating the data to be used for the next pairwise test in accordance with the character decision made aT the end of the current test.
Claim 68
Dependent Claim
74 words
A method in accordance with claim 7 wherein during the performance of each of the pairwise tests of step (4) the set of numbers representative of respective features of the binary raster representation which are used represent the contour of the binary raster representation as seen in directions from outside the binary raster representation, the particular directions being dependent upon the pair of characters to be discriminated by the pairwise test to be performed.
Claim 69
Dependent Claim
89 words
A method in accordance with claim 2 wherein the pairwise tests are included in a plurality of groups, each group being associated with a respective group of characters which are known to have some features in common, the pairwise tests included in each group being those for discriminating between the characters having said common features, and in step (4) the pairwise tests in only one group are performed, said one group being that whose characters have the common features represented by the set of numbers derived in step (3).
Claim 70
Dependent Claim
29 words
A method in accordance with claim 34 wherein each of said groups of tests includes a test for discriminating between all possible pairs of characters associated with the group.
Claim 71
Dependent Claim
70 words
A method in accordance with claim 35 wherein in step (5) the character is identified as a particular character only if during the performance of pairwise tests in step (4) the particular character was determined to be the more likely identity of the character to be identified in a predetermined number of the tests in each of which the particular character was one of the two in the test pair.
Claim 72
Dependent Claim
34 words
A method in accordance with claim 36 wherein said predetermined number is equal to the number of the tests in each of which the particular character was one of two in the test pair.
Claim 73
Dependent Claim
111 words
A method in accordance with claim 34 wherein in step (5) the character is identified as a particular character only if during the performance of pairwise tests in step (4) the particular character was determined to be the more likely identity of the character to be identified in a predetermined number of the tests in each of which the particular character was one of the two in the test pair, and the pairwise tests are performed in step (4) in an order determined by the probabilities of occurrence of the characters to be discriminated to reduce the average number of pairwise tests which otherwise would be performed to identify a character.
Claim 74
Dependent Claim
86 words
A method in accordance with claim 34 wherein for a group of pairwise tests the tests are performed in a sequence such that TIJ precedes TRQ if and only if PI > PR for I not = R and PJ > PQ for I R, where Tij represents a test for discriminating between characters i and j, and PK represents the probability of character K being identified from among all of the characters which are scanned and are discriminated by the pairwise tests in said group.
Claim 75
Dependent Claim
75 words
A method in accordance with claim 39 wherein the data for each pairwise test includes a plurality of weights to be used in computing a respective optimal linear discriminant, threshold values for enabling a character decision to be made after the optimal linear discriminant is computed, and pointer values for indicating the data to be used for the next pairwise test in accordance with the character decision made at the end of the current test.
Claim 76
Independent Claim
26 words
A method to be practiced on a machine for identifying a character on a document as being one of a predetermined set comprising the steps of:
Claim 77
Independent Claim
26 words
A method to be practiced on a machine for identifying a character on a document as being one of a predetermined set comprising the steps of:
Claim 78
Dependent Claim
37 words
A method in accordance with claim 41 wherein said set of numbers represents the numbers and shapes of alternating bumps of opposite convexities as seen looking from at least two different directions outside said binary raster representation.
Claim 79
Dependent Claim
110 words
A method in accordance with claim 41 wherein the features of said binary raster representation which are represented by said set of numbers further include a number which is dependent upon the difference between (a) the sum of numbers proportional to lengths on the two side regions of the binary raster representation which correspond to the absence of parts of the scanned character above a horizontal row positioned in the lower half of the binary raster representation, and (b) a number proportional to a length in the central region of the binary raster representation which corresponds to the absence of a part of the scanned character above said horizontal line.
Claim 80
Dependent Claim
93 words
A method in accordance with claim 41 wherein the features of said binary raster representation which are represented by said set of numbers further include a number which is dependent upon a length in the binary raster representation which corresponds to the absence of a part of the scanned character above a horizontal row positioned in the lower half of the binary raster representation, which length is measured in the vertical direction immediately to the left of the leftmost portion of said horizontal row which corresponds to a part of the scanned character.
Claim 81
Dependent Claim
107 words
A method in accordance with claim 41 wherein the features of said binary raster representation which are represented by said set of numbers further include a number which is dependent upon the difference between (a) a number proportional to a length in the central region of the binary raster representation which corresponds to the absence of a part of the scanned character at the top of the binary raster representation, and (b) the sum of numbers proportional to lengths on the two sides of the binary raster representation which corresponds to the absence of parts of the scanned character at the top of the binary raster representation.
Claim 82
Dependent Claim
67 words
A method in accordance with claim 41 wherein the features of said binary raster representation which are represented by said set of numbers further include a number which is dependent upon the average horizontal width between the leftmost and rightmost portions of the binary raster representation which represents parts of the scanned character taken along horizontal rows of the binary raster representation in the bottom portion thereof.
Claim 83
Dependent Claim
85 words
A method in accordance with claim 41 wherein the features of said binary raster representation which are represented by said set of numbers further include a number which is dependent upon the average horizontal width between the leftmost and rightmost portions of the binary raster representation which represents parts of the scanned character taken along horizontal rows of the binary raster representation in the central region thereof, which central region includes less than half of the total number of rows of the binary raster representation.
Claim 84
Dependent Claim
85 words
A method in accordance with claim 41 wherein the features of said binary raster representation which are represented by said set of numbers further include a number which is dependent upon the average horizontal width between the leftmost and rightmost portions of the binary raster representation which represents parts of the scanned character taken along horizontal rows of the binary raster representation in the central region thereof, Which central region includes more than half of the total number of rows of the binary raster representation.
Claim 85
Dependent Claim
68 words
A method in accordance with claim 41 wherein the features of said binary raster representation which are represented by said set of numbers further include a number which is dependent upon the total number of continuous line segments represented by said binary raster representation along a group of rows thereof, said group consisting of rows in the central region of the upper half of the binary raster representation.
Claim 86
Dependent Claim
68 words
A method in accordance with claim 41 wherein the features of said binary raster representation which are represented by said set of numbers further include a number which is dependent upon the total number of continuous line segments represented by said binary raster representation along a group of rows thereof, said group consisting of rows in the central region of the lower half of the binary raster representation.
Claim 87
Dependent Claim
215 words
A method in accordance with claim 41 wherein step (3) includes the sub-steps of: (3a) computing at least two differently directed histograms for said binary raster representation, (3b) computing a pair of difference strings for said binary raster representation by subtracting each element in each of said differently directed histograms from an adjacent element, (3c) changing the values of pairs of successive elements in each of said difference strings to minimize the effects of noise in said binary raster representation, thereby producing edited differently directed difference strings, (3d) deriving a list of pairwise and direction codes for a sequence of straight-line segments for each of the edited differently directed difference strings in accordance with the element values thereof, the direction of each straight-line segment being one of a predetermined relatively small number, (3e) inserting magnitude and direction codes for additional straight-line segments in each of said lists in accordance with the magnitudes and direction codes for the straight-line segments derived in step (3d) to derive a composite list of straight-line segments whose direction codes change in a predetermined order which causes the successive straight-line segments in each list to represent bumps of alternating opposite convexities, and (3f) combining said lists to derive said set of numbers representative of the features of said binary raster representation.
Claim 88
Dependent Claim
65 words
A method in accordance with claim 51 wherein step (3) further includes the sub-step of: (3g) computing each of a group of special feature numbers from said binary raster representation in accordance with a respective formula, said group of special feature numbers being combined with said lists in sub-step (3f) to derive said set of numbers representative of the features of said binary raster representation.
Claim 89
Dependent Claim
119 words
A method in accordance with claim 41 wherein step (3) includes the sub-steps of: (3a) computing at least two differently directed histograms for said binary raster representation, (3b) computing a pair of lists of straight-line segments from respective ones of said differently directed histograms, the straight-line segments in said lists representing bumps of alternating opposite convexities conforming to the contour of said binary raster representation, (3c) computing each of a group of special feature numbers from said binary raster representation in accordance with a respective formula, and (3d) combining the lists computed in step (3b) and the special feature numbers computed in step (3c) to derive said set of numbers representative of the features of said binary raster representation.
Claim 90
Independent Claim
34 words
A method to be practiced on a machine for recognizing a previously scanned character which is represented as a digitized character as being one of a predetermined set of characters comprising the steps of:
Claim 91
Independent Claim
34 words
A method to be practiced on a machine for recognizing a previously scanned character which is represented as a digitized character as being one of a predetermined set of characters comprising the steps of:
Claim 92
Dependent Claim
56 words
A method in accordance with claim 54 wherein in step (3) the character is recognized as being a particular character in said set only if during the performance of pairwise tests in step (2) the particular character passed a predetermined number of the tests in which it was one of the two in the test pair.
Claim 93
Dependent Claim
34 words
A method in accordance with claim 55 wherein said predetermined number is equal to the number of the tests in each of which the particular character was one of two in the test pair.
Claim 94
Dependent Claim
41 words
A method in accordance with claim 56 wherein the features of said digitized character which are represented by said vector include contour data for said digitized character as seen looking in at least two different directions from outside the digitized character.
Claim 95
Dependent Claim
42 words
A method in accordance with claim 54 wherein prior to step (1) the digitized character is operated upon to stretch it in at least one direction such that the stretched digitized character has a predetermined length in said at least one direction.
Claim 96
Dependent Claim
25 words
A method in accordance with claim 58 wherein prior to step (1) the digitized character is operated upon to correct breaks in said one direction.
Claim 97
Dependent Claim
35 words
A method in accordance with claim 54 wherein the features of said digitized character which are represented by said vector include contour data for said digitized character as seen looking from outside said digitized character.
Claim 98
Dependent Claim
94 words
A method in accordance with claim 60 wherein the pairwise tests are included in a plurality of groups, the groups being associated with respective contour data sets and the pairwise tests included in the respective groups being those for discriminating between characters whose contour data features correspond to respective contour data sets, and in step (2) the only pairwise tests which are performed are those in the group for discriminating between characters whose contour data features correspond to the contour data set which is applicable to the contour data features represented by said vector.
Claim 99
Dependent Claim
45 words
A method in accordance with claim 61 wherein each of said groups of tests includes a test for discriminating between each possible pair of characters in said predetermined set whose contour data features correspond to the contour data set which is associated with the group.
Claim 100
Dependent Claim
98 words
A method in accordance with claim 62 wherein in step (3) the digitized character is recognized as being a particular character in said set only if during the performance of pairwise tests in step (2) the particular character passed a predetermined number of the tests in which it was one of the two in the test pair, and the pairwise tests are performed in step (2) in an order determined by the probabilities of occurrence of the characters to be discriminated to reduce the average number of pairwise tests which otherwise would be performed to recognize a character.
Claim 101
Dependent Claim
104 words
A method in accordance with claim 60 wherein the features of said digitized character which are represented by said vector further include a number which is dependent upon the difference between (a) the sum of numbers proportional to lengths on the two side regions of the digitized character which correspond to the absence of parts of the digitized character above a horizontal row positioned in the lower half of the digitized character, and (b) a number proportional to a length in the central region of the digitized character which corresponds to the absence of a part of the digitized character above said horizontal row.
Claim 102
Dependent Claim
88 words
A method in accordance with claim 60 wherein the features of said digitized character which are represented by said vector further include a number which is dependent upon a length in the digitized character which corresponds to the absence of a part of the digitized character above a horizontal row positioned in the lower half of the digitized character, which length is measured in the vertical direction immediately to the left of the leftmost portion of said horizontal row which corresponds to a part of the digitized character.
Claim 103
Dependent Claim
94 words
A method in accordance with claim 60 wherein the features of said digitized character which are represented by said vector further include a number which is dependent upon the difference between (a) a number proportional to a length in the central region of the digitized character which corresponds to the absence of a part of the digitized character at the top thereof, and (b) the sum of numbers proportional to lengths on the two sides of the digitized character which correspond to the absence of parts of the digitized character at the top thereof.
Claim 104
Dependent Claim
62 words
A method in accordance with claim 60 wherein the features of said digitized character which are represented by said vector further include a number which is dependent upon the average horizontal width between the leftmost and rightmost portions of the digitized character which represents part of the digitized character taken along horizontal rows of the digitized character in the bottom portion thereof.
Claim 105
Dependent Claim
79 words
A method in accordance with claim 60 wherein the features of said digitized character which are represented by said vector further include a number which is dependent upon the average horizontal width between the leftmost and rightmost portions of the digitized character which represents parts of the digitized character taken along horizontal rows of the digitized character in the central region thereof, which central region includes less than half of the total number of rows of the digitized character.
Claim 106
Dependent Claim
79 words
A method in accordandance with claim 60 wherein the features of said digitized character which are represented by said vector further include a number which is dependent upon the average horizontal width between the leftmost and rightmost portions of the digitized character which represents parts of the digitized character taken along horizontal rows of the digitized character in the central region thereof, which central region includes more than half of the total number of rows of the digitized character.
Claim 107
Dependent Claim
63 words
A method in accordance with claim 60 wherein the features of said digitized character which are represented by said vector further include a number which is dependent upon the total number of continuous line segments represented by said digitized character along a group of rows thereof, said group consisting of rows in the central region of the upper half of the digitized character.
Claim 108
Dependent Claim
63 words
A method in accordance with claim 60 wherein the features of said digitized character which are represented by said vector further include a number which is dependent upon the total number of continuous line segments represented by said digitized character along a group of rows thereof, said group consisting of rows in the central region of the lower half of the digitized character.
Claim 109
Dependent Claim
211 words
A method in accordance with claim 60 wherein step (1) includes the sub-steps of: (1a) computing at least two differently directed histograms for said digitized character, (1b) computing a pair of difference strings for said digitized character by subtracting each element in each of said differently directed histograms from an adjacent element, (1c) changing the values of pairs of successive elements in each of said difference strings to minimize the effects of noise in said digitized character, thereby producing edited differently directed difference strings, (1d) deriving a list of magnitude and direction codes for a sequence of straight-Line segments for each of the edited differently directed difference strings in accordance with the element values thereof, the direction of each straight-line segment being one of a predetermined relatively small number, (1e) inserting magnitude and direction codes for additional straight-line segments in each of said lists in accordance with the magnitude and direction codes for the straight-line segments derived in step (2d) to derive a composite list of straight-line segments whose direction codes change in a predetermined order which causes the successive straight-line segments in each list to represent bumps of alternating opposite convexities, and (1f) combining said lists to derive said set of numbers representative of the features of said digitized character.
Claim 110
Dependent Claim
64 words
A method in accordance with claim 72 wherein step (1) further includes the sub-step of: (1g) computing each of a group of special feature numbers from said differently directed histograms in accordance with a respective formula, said group of special feature numbers being combined with said lists in sub-step (1f) to derive said set of numbers representative of the features of said digitized characters.
Claim 111
Dependent Claim
116 words
A method in accordance with claim 60 wherein step (1) includes the sub-steps of: (1a) computing at least two differently directed histograms for said digitized character, (1b) computing a pair of lists of straight-line segments from respective ones of said differently directed histograms, the straight-line segments in said lists representing bumps of alternating opposite convexities conforming to the contour of said digitized character, (1c) computing each of a group of special feature numbers from said differently directed histograms in accordance with a respective formula, and (1d) combining the lists computed in step (1b) and the special feature numbers computed in step (1c) to derive said set of numbers representative of the features of said digitized character.
Claim 112
Dependent Claim
94 words
A method in accordance with claim 74 wherein the pairwise tests are included in a plurality of groups, the groups being associated with respective contour data sets and the pairwise tests included in the respective groups being those for discriminating between characters whose contour data features correspond to respective contour data sets, and in step (2) the only pairwise tests which are performed are those in the group for discriminating between characters whose contour data features correspond to the contour data set which is applicable to the contour data features represented by said vector.
Claim 113
Dependent Claim
45 words
A method in accordance with claim 75 wherein each of said groups of tests includes a test for discriminating between each possible pair of characters in said predetermined set whose contour data features correspond to the contour data set which is associated with the group.
Claim 114
Dependent Claim
98 words
A method in accordance with claim 76 wherein in step (3) the digitized character is recognized as being a particular character in said set only if during the performance of pairwise tests in step (2) the particular character passed a predetermined number of the tests in which it was one of the two in the test pair, and the pairwise tests are performed in step (2) in an order determined by the probabilities of occurrence of the characters to be discriminated to reduce the average number of pairwise tests which otherwise would be performed to recognize a character.
Claim 115
Dependent Claim
36 words
A method in accordance with claim 77 wherein each of the pairwise tests performed in step (2) is the computation of an optimal linear discriminant designed to distinguish between the two characters of the respective pair.
Claim 116
Dependent Claim
56 words
A method in accordance with claim 78 wherein in step (3) the character is recognized as being a particular character in said set only if during the performance of pairwise tests in step (2) the particular chaRacter passed a predetermined number of the tests in which it was one of the two in the test pair.
Claim 117
Dependent Claim
82 words
A method in accordance with claim 61 wherein for a group of pairwise tests the tests are performed in a sequence such that TIJ precedes TRQ if and only if PI>PR for I not = R and PJ>PQ for I R, where Tij represents a test for discriminating between character i and j, and PK represents the probability of character K being recognized from among all of the characters which are digitized and are discriminated by the pairwise tests in said group.
Claim 118
Dependent Claim
56 words
A method in accordance with claim 80 wherein in step (3) the character is recognized as being a particular character in said set only if during the performance of pairwise tests in step (2) the particular character passed a predetermined number of the tests in which it was one of the two in the test pair.
Claim 119
Dependent Claim
34 words
A method in accordance with claim 81 wherein said predetermined number is equal to the number of the tests in each of which the particular character was one of two in the test pair.
Claim 120
Dependent Claim
75 words
A method in accordance with claim 80 wherein the data for each pairwise test includes a plurality of weights to be used in computing a respective optimal linear discriminant, threshold values for enabling a character decision to be made after the optimal linear discriminant is computed, and pointer valves for indicating the data to be used for the next pairwise test in accordance with the character decision made at the end of the current test.
Claim 121
Dependent Claim
75 words
A method in accordance with claim 61 wherein the data for each pairwise test includes a plurality of weights to be used in computing a respective optimal linear discriminant, threshold values for enabling a character decision to be made after the optimal linear discriminant is computed, and pointer values for indicating the data to be used for the next pairwise test in accordance with the character decision made at the end of the current test.
Claim 122
Dependent Claim
65 words
A method in accordance with claim 60 wherein during the performance of each of the pairwise tests of step (2) only some of the elements of said vector are utilized, the elements representing contour data features as seen in directions from outside the dizitized character, the particular directions being dependent upon the pair of characters to be discriminated by the pairwise test to be performed.
Claim 123
Dependent Claim
87 words
A method in accordance with claim 55 wherein the pairwise tests are included in a plurality of groups, each group being associated with a respective group of characters which are known to have some features in common, the pairwise tests included in each group being those for discriminating between the characters having said common features, and in step (2) the pairwise tests in only one group are performed, said one group being that whose characters have the common features represented by the vector constructed in step (1).
Claim 124
Dependent Claim
29 words
A method in accordance with claim 86 wherein each of said groups of tests includes a test for discriminating between all possible pairs of characters associated with the group.
Claim 125
Dependent Claim
56 words
A method in accordance with claim 87 wherein in step (3) the character is recognized as being a particular character in said set only if during the performance of pairwise tests in step (2) the particular character passed a predetermined number of the tests in which it was one of the two in the test pair.
Claim 126
Dependent Claim
34 words
A method in accordance with claim 88 wherein said predetermined number is equal to the number of the tests in each of which the particular character was one of two in the test pair.
Claim 127
Dependent Claim
98 words
A method in accordance with claim 86 wherein in step (3) the digitized character is recognized as being a particular character in said set only if during the performance of pairwise tests in step (2) the particular character passed a predetermined number of the tests in which it was one of the two in the teSt pair, and the pairwise tests are performed in step (2) in an order determined by the probabilities of occurrence of the characters to be discriminated to reduce the average number of pairwise tests which otherwise would be performed to recognize a character.
Claim 128
Dependent Claim
82 words
A method in accordance with claim 86 wherein for a group of pairwise tests the tests are performed in a sequence such that TIJ precedes TRQ if and only if PI>PR for I not = R and PJ>PQ for I R, where Tij represents a test for discriminating between characters i and j, and PK represents the probability of character K being recognized from among all of the characters which are digitized and are discriminated by the pairwise tests in said group.
Claim 129
Dependent Claim
75 words
A method in accordance with claim 91 wherein the data for each pairwise test includes a plurality of weights to be used in computing a respective optimal linear discriminant, threshold values for enabling a character decision to be made after the optimal linear discriminant is computed, and pointer values for indicating the data to be used for the next pairwise test in accordance with the character decision made at the end of the current test.
Claim 130
Dependent Claim
36 words
A method in accordance with claim 55 wherein each of the pairwise tests performed in step (2) is the computation of an optimal linear discriminant designed to distinguish between the two characters of the respective pair.
Claim 131
Dependent Claim
75 words
A method in accordance with claim 55 wherein the data for each pairwise test includes a plurality of weights to be used in computing a respective optimal linear discriminant, threshold values for enabling a character decision to be made after the optimal linear discriminant is computed, and pointer values for indicating the data to be used for the next pairwise test in accordance with the character decision made at the end of the current test.
Claim 132
Dependent Claim
36 words
A method in accordance with claim 54 wherein each of the pairwise tests performed in step (2) is the computation of an optimal linear discriminant designed to distinguish between the two characters of the respective pair.
Claim 133
Dependent Claim
75 words
A method in accordance with claim 54 wherein the data for each pairwise test includes a plurality of weights to be used in computing a respective optimal linear discriminant, threshold values for enabling a character decision to be made after the optimal linear discriminant is computed, and pointer values for indicating the data to be used for the next pairwise test in accordance with the character decision made at the end of the current test.
Claim 134
Dependent Claim
58 words
A method in accordance with claim 54 wherein in step (3) the character is recognized as being a particular character in said set only if during the performance of pairwise tests in step (2) the particular character passed more of the tests in which it was one of the two in the test pair than any other character.
Claim 135
Dependent Claim
41 words
A method in accordance with claim 87 wherein the features of said digitized character which are represented by said vector include contour data for said digitized character as seen looking in at least two different directions from outside the digitized character.
Claim 136
Dependent Claim
94 words
A method in accordance with claim 98 wherein the pairwise tests are included in a plurality of groups, the groups being associated with respective contour data sets and the pairwise tests included in the respective groups being those for discriminating between characters whose contour data features correspond to respective contour data sets, and in step (2) the only pairwise tests which are performed are those in the group for discriminating between characters whose contour data features correspond to the contour data set which is applicable to the contour data features represented by said vector.
Claim 137
Independent Claim
28 words
A method for using apparatus to design a machine program for recognizing a digitized character as being one of a predetermined group of characters comprising the steps of:
Claim 138
Independent Claim
28 words
A method for using apparatus to design a machine program for recognizing a digitized character as being one of a predetermined group of characters comprising the steps of:
Claim 139
Dependent Claim
66 words
A method in accordance with claim 100 wherein prior to the execution of step (3) a plurality of sets of characteristics descriptive of a feature set are identified, and in step (3) a set of discriminants and associated threshold values is computed for each of the characteristic sets in said plurality for discriminating between the character classes whose feature sets exhibit the respective set of characteristics.
Claim 140
Dependent Claim
37 words
A method in accordance with claim 101 wherein said set of features includes a representation of contour data for a character, and said sets of characteristics are descriptive of contour data represented by a set of features.
Claim 141
Independent Claim
22 words
A method to be practiced on a machine for recognizing a character as one of a predetermined set comprising the steps of:
Claim 142
Independent Claim
22 words
A method to be practiced on a machine for recognizing a character as one of a predetermined set comprising the steps of:
Claim 143
Dependent Claim
71 words
A method in accordance with claim 103 wherein said pairwise tests are performed in a sequence such that TIJ precedes TRQ if and only if PI>PR for I not = R and PJ>PQ for I R, where Tij represents a test for discriminating between character classes i and j, and PK represents the probability of character class K, as opposed to all other character classes, containing the character to be recognized.
Claim 144
Dependent Claim
30 words
A method in accordance with claim 104 wherein each of the tests performed in step (1) is the computation of a linear discriminant designed to distinguish between two character classes.
Claim 145
Dependent Claim
34 words
A method in accordance with claim 105 wherein the linear discriminant computed during each test performed in step (1) is a function of data representing external contour patterns of the character to be recognized.
Claim 146
Dependent Claim
203 words
A method in accordance with claim 103 wherein in step (1) two lists are maintained, the first being a list containing an entry for each character class, which entry is the number of pairwise tests performed in which said character class was the one of the two in the pair which was determined to have the greater probability of containing the character to be recognized, and the second being a list containing an entry for each character class, which entry is an indication of the performance of at least one test in which said character clasS was one of the two in the test pair and was not determined to have the greater probability of containing the character to be recognized, and said two lists are updated following the performance of each pairwise test, the presence of condition (a) is detected by observing an indication in said second list of an entry for each character class, and the presence of condition (b) is detected by observing a number for the entry for any character class in said first list which is equal to the number of pairwise tests which include said any character class as one of the two in the test pair.
Claim 147
Dependent Claim
33 words
A method in accordance with claim 107 wherein the tests performed in step (2) serves to discriminate between respective pairs of characters in said predetermined set relative to a character to be recognized.
Claim 148
Dependent Claim
23 words
A method in accordance with claim 108 wherein each of the tests performed in step (2) is the computation of a linear discriminant.
Claim 149
Dependent Claim
54 words
A method in accordance with claim 109 wherein in step (2) the character is recognized as being a particular character in said set if during the performance of the pairwise tests the associated character class passed a predetermined number of the tests in which it was one of the two in the test pair.
Claim 150
Dependent Claim
48 words
A method in accordance with claim 110 wherein the pairwise tests are performed in step (2) in an order determined by the probabilities of occurrence of the characters in said set to reduce the average number of pairwise tests which otherwise would be performed to recognize a character.
Claim 151
Dependent Claim
33 words
A method in accordance with claim 103 wherein the tests performed in step (2) serve to discriminate between respective pairs of characters in said predetermined set relative to said character to be recognized.
Claim 152
Dependent Claim
23 words
A method in accordance with claim 112 wherein each of the tests performed in step (2) is the computation of a linear discriminant.
Claim 153
Dependent Claim
48 words
A method in accordance with claim 113 wherein the pairwise tests are performed in step (2) in an order determined by the probabilities of occurrence of the characters in said set to reduce the average number of pairwise tests which otherwise would be performed to recognize a character.
Claim 154
Dependent Claim
23 words
A method in accordance with claim 103 wherein each of the tests performed in step (2) is the computation of a linear discriminant.
Claim 155
Dependent Claim
48 words
A method in accordance with claim 115 wherein the pairwise tests are performed in step (2) in an order determined by the probabilities of occurrence of the characters in said set to reduce the average number of pairwise tests which otherwise would be performed to recognize a character.
Claim 156
Dependent Claim
48 words
A method in accordance with claim 103 wherein the pairwise tests are performed in step (2) in an order determined by the probabilities of occurrence of the characters in said set to reduce the average number of pairwise tests which otherwise would be performed to recognize a character.
Claim 157
Dependent Claim
203 words
A method in accordance with claim 117 wherein in step (1) two lists are maintained, the first being a list containing an entry for each character class, which entry is the number of pairwise tests performed in which said character class was the one of the two in the pair which was determined to have the greater probability of containing the character to be recognized, and the second being a list containing an entry for each character class, which entry is an indication of the performance of at least one test in which said character class was one of the two in the test pair and was not determined to have the greater probability of containing the character to be recognized, and said two lists are updated following the performance of each pairwise test, the presence of condition (a) is detected by observing an indication in said second list of an entry for each character class, and the presence of condition (b) is detected by observing a number for the entry for any character class in said first list which Is equal to the number of pairwise tests which include said any character class as one of the two in the test pair.
Claim 158
Independent Claim
28 words
A method to be practiced on a machine for recognizing a character in digitized form as being one of a predetermined set of characters comprising the steps of:
Claim 159
Independent Claim
28 words
A method to be practiced on a machine for recognizing a character in digitized form as being one of a predetermined set of characters comprising the steps of:
Claim 160
Dependent Claim
21 words
A method in accordance with claim 119 wherein said tests discriminate respective pairs of characters in the respective sub-set of characters.
Claim 161
Dependent Claim
19 words
A method in accordance with claim 120 wherein each of said tests is the computation of a linear discriminant.
Claim 162
Dependent Claim
54 words
A method in accordance with claim 120 wherein the pairwise tests are performed in step (3) in an order determined by the probabilities of occurrence of the characters in the sub-set associated with the selected test group to reduce the average number of pairwise tests which otherwise would be performed to recognize a character.
Claim 163
Dependent Claim
26 words
A method in accordance with claim 120 wherein the elements of the vector constructed in step (1) are non-binary, continuous measures of features of the character.
Claim 164
Dependent Claim
26 words
A method in accordance with claim 119 wherein the elements of the vector constructed in step (1) are non-binary, continuous measures of features of the character.
Claim 165
Dependent Claim
52 words
A method in accordance with claim 119 wherein the tests are performed in step (3) in an order determined by the probabilities of occurrence of the characters in the sub-set associated with the selected test group to reduce the average number of tests which otherwise would be performed to recognize a character.
Claim 166
Dependent Claim
19 words
A method in accordance with claim 119 wherein each of said tests is the computation of a linear discriminant.
Claim 167
Dependent Claim
26 words
A method in accordance with claim 119 wherein the elements of the vector constructed in step (1) are non-binary, continuous measures of features of the character.
Claim 168
Independent Claim
26 words
A method to be practiced on a machine for recognizing a digitized character as being one of a predetermined set of characters comprising the steps of:
Claim 169
Independent Claim
26 words
A method to be practiced on a machine for recognizing a digitized character as being one of a predetermined set of characters comprising the steps of:
Claim 170
Dependent Claim
31 words
A method in accordance with claim 128 wherein said vector elements represent the numbers, shapes and locations of alternating bumps of opposite convexities as seen looking from outside said digitized character.
Claim 171
Dependent Claim
29 words
A method in accordance with claim 128 wherein each of the tests performed in step (2) is the computation of a linear discriminant designed to distinguish between two characters.
Claim 172
Dependent Claim
34 words
A method in accordance with claim 130 wherein the linear discriminant computed during each test performed in step (2) is a function of data representing external contour patterns of the character to be recognized.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-27 | 1977-02-26 | 1977-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-27 | 1981-02-26 | 1981-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-27 | 1985-02-26 | 1985-08-28 | $7700.00 | Window Closed / Lapsed |