Optical character recognition method and apparatus
DC CAFCFirst Claim
1. A method for performing optical character recognition of textual material on a medium, said medium having at least one array element, said method identifying said array element as consisting essentially of text or as comprising non-text, said identification of said array element as consisting essentially of text, comprising the steps of;
- (a) determining whether the number of on-bits in a first predetermined number of bytes of said array element is greater than or equal to a second predetermined number and less than or equal to a third predetermined number; and
(b) determining whether the number of phase changes from on-bits to off-bits in said first predetermined number of bytes of said array element is greater than or equal to a fourth predetermined number and less than or equal to a fifth predetermined number.
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Abstract
A system for recognition of characters on a medium. The system includes a scanner for scanning a medium such as a page of printed text and graphics and producing a bit-mapped representation of the page. The bit-mapped representation of the page is then stored in a memory means such as the memory of a computer system. A processor processes the bit-mapped image to produce an output comprising coded character representation of the text on the page. The present invention discloses parsing a page to allow for production of the output characters in a logical sequence, a combination of feature detection methods and template matching methods for recognition of characters and a number of methods for feature detection such as use of statistical data and polygon fitting.
88 Citations
15 Claims
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1. A method for performing optical character recognition of textual material on a medium, said medium having at least one array element, said method identifying said array element as consisting essentially of text or as comprising non-text, said identification of said array element as consisting essentially of text, comprising the steps of;
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(a) determining whether the number of on-bits in a first predetermined number of bytes of said array element is greater than or equal to a second predetermined number and less than or equal to a third predetermined number; and (b) determining whether the number of phase changes from on-bits to off-bits in said first predetermined number of bytes of said array element is greater than or equal to a fourth predetermined number and less than or equal to a fifth predetermined number. - View Dependent Claims (2)
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3. A system for optically scanning a medium, said medium having thereon an unknown character, said system comprising:
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scanning means for scanning said medium, said scanning means providing as output a bit-mapped image of said medium; a first memory means coupled with said scanning means for storing said bit-mapped image; a second memory means for storing a plurality of bit-mapped templates representing known characters; processing means coupled with said first memory means and said second memory means, said processing means including means for parsing said bit-mapped image of said medium and providing as output a bit-mapped representation of said unknown character, means for generating polygon representations descriptive of the shape of said unknown character, means for generating statistical information concerning said polygon representations and means for analyzing said statistical information to identify said unknown character. - View Dependent Claims (4, 5, 6, 7, 8)
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9. A method for performing optical character recognition of textual material on a medium, said medium having at least one array element, said method identifying said array element as consisting essentially of text or as comprising non-text, said identification of said array element as consisting essentially of text, comprising the steps of:
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(a) determining whether the number of bits in a first state in a predetermined set of bits of said array element is within a first range of values; and (b) determining whether the number of phase changes from said first state to a second state of said predetermined set of bits of said array element is within a second range of values. - View Dependent Claims (10)
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11. In an optical character recognition system, a method for identifying a bit-mapped image of an unknown character, comprising the steps of:
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(a) generating polygon representations descriptive of the shape of said unknown character; (b) generating statistical information from said polygon representations descriptive of the shape of said unknown character, and (c) analyzing said statistical information to identify said unknown character. - View Dependent Claims (13)
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12. In an optical character recognition system, a method for identifying a bit-mapped image of an unknown character, comprising the steps of:
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(a) comparing said bit-mapped image of an unknown character with each of a plurality of templates in a template cache; (b) determining if said bit-mapped image of an unknown character matches any of said plurality of templates in said template cache; if said bit-mapped image of an unknown character does not match any of said plurality of templates in said template cache; (c) generating polygon representations descriptive of the shape of said unknown character, (d) generating statistical information from said polygon representations descriptive of the shape of said unknown character; and (e) analyzing said statistical information to identify said unknown character. - View Dependent Claims (14)
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15. A system for optically scanning a medium for determining if said medium is comprised essential of text of non-text, said medium having thereon an unknown character, said system comprising:
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scanning means for scanning said medium, said scanning means providing as output a bit-mapped image of said medium; a first memory means coupled with said scanning means for storing said bit-mapped image; processing means for discriminating text from non-text coupled with said first memory means, said processing means including means for generating at least one array element from said bit mapped image, means for determining that the number of on-bits in a first predetermined number of bytes of said array element is greater than or equal to a second predetermined number and less than or equal to a third predetermined number and means for determining that the number of phase changes from on-bits to off-bits in said first predetermined number of bytes of said array element is greater than or equal to a fourth predetermined number and less than or equal to a fifth predetermined number.
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Specification