US5091968A — Optical character recognition system and method

Claim 1

Independent Claim 205 words

Optical character recognition system comprising: means for optically scanning a character recorded on a document, the character and document having different opacities, and producing a plurality of gray-scale values corresponding to said opacities, said gray-scale values representing light and dark pixels: memory means disposed for storing the gray-scale values, said memory means including a stored program, and predetermined data including a plurality of predetermined binary patterns, one of said predetermined binary patterns representing the character, each predetermined binary pattern including first, second, and third bit configuration, said first bit configuration representing an actual bit pattern of the character, said second bit configuration representing predetermined significance of respective bits of the actual bit pattern, and said third bit configuration representing weighted values of respective bits of the actual bit pattern; and processing means coupled to the scanning means and to the memory means, and operating under control of the stored program, for locating the character on the document by selecting from said gray-scale values a matrix of values representative of the character, for converting the matrix values to binary data, and for selecting from the plurality of predetermined binary patterns a pattern that matches the converted binary data, said matching pattern serving to identify the character.

Claim 2

Dependent Claim 205 words

Optical character recognition system comprising: means for optically scanning a character recorded on a document, the character and document having different opacities, and producing a plurality of gray-scale values corresponding to said opacities, said gray-scale values representing light and dark pixels: memory means disposed for storing the gray-scale values, said memory means including a stored program, and predetermined data including a plurality of predetermined binary patterns, one of said predetermined binary patterns representing the character, each predetermined binary pattern including first, second, and third bit configuration, said first bit configuration representing an actual bit pattern of the character, said second bit configuration representing predetermined significance of respective bits of the actual bit pattern, and said third bit configuration representing weighted values of respective bits of the actual bit pattern; and processing means coupled to the scanning means and to the memory means, and operating under control of the stored program, for locating the character on the document by selecting from said gray-scale values a matrix of values representative of the character, for converting the matrix values to binary data, and for selecting from the plurality of predetermined binary patterns a pattern that matches the converted binary data, said matching pattern serving to identify the character.

Claim 3

Dependent Claim 38 words

The system as in claim 1 wherein said character has a right, left, top and bottom edge, and said scanning means includes a means for reading from the bottom edge to the top edge in a vertical direction.

Claim 4

Dependent Claim 27 words

The system as in claim 2 wherein said processing means includes a means for framing a region having a plurality of pixels proximate to a dark pixel.

Claim 5

Dependent Claim 21 words

The system as in claim 3 wherein said framing means includes a means for defining a window for bordering said region.

Claim 6

Dependent Claim 56 words

The system as in claim 4 wherein said framing means includes a means for positioning the window so that the sum of the gray-scale values within the window is a maximum, corresponding to the character being centrally located in the window, said maximum-sum values corresponding to a matrix of selected pixel values representative of the character.

Claim 7

Dependent Claim 40 words

The system as in claim 5 wherein said framing means also includes a means for confirming the presence of a character within the window, by determining the total number of pixels in the window that exceeds a predetermined confirmation threshold.

Claim 8

Dependent Claim 24 words

The system as in claim 6 wherein said processing means includes a means for calculating an average threshold value for said selected pixel values.

Claim 9

Dependent Claim 32 words

The system as in claim 7 wherein said calculating means includes a means for producing binary data representative of the magnitudes of said selected pixel values relative to said average threshold value.

Claim 10

Dependent Claim 42 words

The system as in claim 8 wherein said processing means includes a means for producing a mismatch count for each predetermined binary pattern said count being indicative of the extent of mismatch between the predetermined binary pattern and the converted binary data.

Claim 11

Dependent Claim 34 words

The system as in claim 9 wherein said means for producing a mismatch count includes a means for selecting from the mismatch counts the count that best satisfies at least one predetermined threshold criterion.

Claim 12

Dependent Claim 58 words

The system as in claim 10 wherein the means for producing a mismatch count includes a means for producing mismatch words and calculating a count based on the contents of selected ones of said words, said words being indicative of the extent of mismatch between the converted binary data and selected bit configurations of said predetermined binary pattern.

Claim 13

Dependent Claim 39 words

The system as in claim 11 wherein said means for producing a mismatch count includes a logic means for performing an exclusive-OR operation between the converted binary data and the first bit configuration to produce a first mismatch word.

Claim 14

Dependent Claim 39 words

The system as in claim 12 wherein said means for producing a mismatch count includes a logic means for performing an AND operation between the first mismatch work and the second bit configuration to produce a second mismatch word.

Claim 15

Dependent Claim 39 words

The system as in claim 13 wherein said means for producing a mismatch count includes a logic means for performing an AND operation between the second mismatch word and the third bit configuration to produce a third mismatch word.

Claim 16

Dependent Claim 64 words

The system as in claim 14 wherein each of said predetermined binary patterns represents a predetermined template, and said framed character may be compared against a predetermined template in each of nine positions, a center position and eight non-center positions, and said means for producing a mismatch count includes a means for positioning a template relative to the center portion of the framed character.

Claim 17

Dependent Claim 27 words

The system as in claim 15 wherein said means for positioning places the predetermined binary pattern relative to one of the non-center portions of the framed character.

Claim 18

Dependent Claim 17 words

The system as in claim 16 wherein said gray-scale values are in the range 0 to 255.

Claim 19

Dependent Claim 17 words

The system as in claim 17 wherein said character is a member of a selected character set.

Claim 20

Dependent Claim 22 words

The system as in claim 18 wherein said character and said window are each of a predetermined size for a selected font.

Claim 21

Dependent Claim 30 words

The system as in claim 19 wherein each bit-configuration of said predetermined binary pattern is a first predetermined number of pixels wide by a second predetermined number of pixels high.

Claim 22

Dependent Claim 144 words

Method of optically identifying a character on a document, the character and document having different opacites, the method comprising the steps of: optically scanning the document and producing a plurality of gray-scale values corresponding to said opacities, said gray-scale values representing light and dark pixels; locating the character by selecting, from said gray-scale values, a matrix of values representative of the character; converting the matrix values to binary data; representing the character as one of a plurality of predetermined binary pattern including first, second, and third bit configurations, said first bit configuration representing an actual bit pattern of the character, said second bit configuration representing predetermined significance of respective bits of the actual bit pattern, and said third bit configuration representing weighted values of respective bits of the actual bit pattern; and selecting from the plurality of predetermined binary patterns a pattern that matches.

Claim 23

Dependent Claim 144 words

Method of optically identifying a character on a document, the character and document having different opacites, the method comprising the steps of: optically scanning the document and producing a plurality of gray-scale values corresponding to said opacities, said gray-scale values representing light and dark pixels; locating the character by selecting, from said gray-scale values, a matrix of values representative of the character; converting the matrix values to binary data; representing the character as one of a plurality of predetermined binary pattern including first, second, and third bit configurations, said first bit configuration representing an actual bit pattern of the character, said second bit configuration representing predetermined significance of respective bits of the actual bit pattern, and said third bit configuration representing weighted values of respective bits of the actual bit pattern; and selecting from the plurality of predetermined binary patterns a pattern that matches.

Claim 24

Dependent Claim 31 words

The method of claim 21 where the step of optically scanning the document includes the step of reading each character on the document from bottom to top in a vertical direction.

Claim 25

Dependent Claim 29 words

The method of claim 22 where the step of locating the character includes the step of framing a region having a plurality of pixels proximate to a dark pixel.

Claim 26

Dependent Claim 21 words

The method of claim 23 where the step of framing includes the step of defining a window for bordering said region.

Claim 27

Dependent Claim 57 words

The method of claim 24 where the step of framing also includes the step of positioning the window so that the sum of the gray-scale values within the window is a maximum, corresponding to the character being centrally located in the window, said maximum-sum values corresponding to a matrix of selected pixel values representative of the character.

Claim 28

Dependent Claim 41 words

The method of claim 2 where the step of framing the character includes the step of confirming the presence of a character within the window, by determining the total number of pixels in the window that exceeds a predetermined confirmation threshold.

Claim 29

Dependent Claim 31 words

The method of claim 26 where the step of converting includes the step of calculating an average threshold value from the values represented by the dark pixels of the framed character.

Claim 30

Dependent Claim 33 words

The method of claim 27 where the step of converting also includes the step of producing binary data representative of the magnitudes of said selected pixel values relative to said average threshold value.

Claim 31

Dependent Claim 52 words

The method of claim 28 where the step of selecting a predetermined binary pattern that matches the converted binary data includes the step of producing a mismatch count for each predetermined binary pattern, said count being indicative of the extent of mismatch between the predetermined binary pattern and the converted binary data.

Claim 32

Dependent Claim 35 words

The method of claim 29 wherein the step of selecting a predetermined binary pattern also includes the step of selecting from the mismatch counts the count that best satisfies at least one predetermined threshold criterion.

Claim 33

Dependent Claim 57 words

The method of claim 30 where the step of producing a mismatch count includes the steps of producing mismatch words and calculating a count based on the contents of selected ones of said words, said words being indicative of the extent of mismatch between the converted binary data and selected bit configurations of said predetermined binary pattern.

Claim 34

Dependent Claim 38 words

The method of claim 31 where the step of producing a mismatch count includes the step of performing an exclusive-OR logical operation between the converted binary data and the first bit configuration for producing a first mismatch word.

Claim 35

Dependent Claim 38 words

The method of claim 32 where the step of producing a mismatch count includes the step of performing an AND logical operation between the first mismatch words and the second bit configuration for producing a second mismatch word.

Claim 36

Dependent Claim 38 words

The method of claim 33 where the step of producing a mismatch count further includes the step of performing AND logical operation between the second mismatch word and the third bit configuration for producing a third mismatch word.

Claim 37

Dependent Claim 49 words

The method of claim 34 where the framed character may be divided virtually into nine portions, a center portion and eight non-center portions, and the step of producing a mismatch count includes the step of positioning a predetermined binary pattern relative to the center portion of the framed character.

Claim 38

Dependent Claim 28 words

The method of claim 35 where the step of positioning includes placing the predetermined binary pattern relative to one of the eight non-center portions of the framed character.

Claim 39

Dependent Claim 154 words

Method of identifying a character imaged on a document, the character and document having different opacities, the document being optically scanable, with images thereon representable as a plurality of stored gray-scale pixel values corresponding to said opacities, the method comprising the steps of: locating the character by selecting from said gray-scale pixel values a matrix of values representing the character; converting the matrix value to binary data; representing the character as one of a plurality of predetermined binary patterns, each predetermine binary pattern including first, second, and third bit configuration, said first bit configuration representing an actual bit pattern of the character, said second bit configuration representing predetermined significance of respective bits of the actual bit pattern, and said third bit configuration representing weighted values of respective bits of the actual bit pattern; and identifying the character by selecting, from the plurality of predetermined binary patterns, a pattern that matches the converted binary data.

Claim 40

Dependent Claim 154 words

Method of identifying a character imaged on a document, the character and document having different opacities, the document being optically scanable, with images thereon representable as a plurality of stored gray-scale pixel values corresponding to said opacities, the method comprising the steps of: locating the character by selecting from said gray-scale pixel values a matrix of values representing the character; converting the matrix value to binary data; representing the character as one of a plurality of predetermined binary patterns, each predetermine binary pattern including first, second, and third bit configuration, said first bit configuration representing an actual bit pattern of the character, said second bit configuration representing predetermined significance of respective bits of the actual bit pattern, and said third bit configuration representing weighted values of respective bits of the actual bit pattern; and identifying the character by selecting, from the plurality of predetermined binary patterns, a pattern that matches the converted binary data.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1995-02-24	1995-08-26	1996-02-25	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1999-02-24	1999-08-26	2000-02-25	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2003-02-24	2003-08-26	2004-02-25	$7700.00	Window Closed / Lapsed

Optical character recognition system and method

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