Method and apparatus for currency discrimination
First Claim
1. An improved method for discriminating between currency bills of different denominations comprising the acts of:
- illuminating a predetermined section of a currency bill by focusing at least one strip of light thereupon;
detecting the light reflected off said illuminated section of said bill to generate an analog reflectance signal;
generating relative lateral displacement between said strip of light and said bill so as to illuminate and optically scan successive sections of said bill along a predetermined dimension thereof;
obtaining a series of analog reflectance signals corresponding to light reflected from each of said successive bill sections;
digitizing and processing said series of analog reflectance signals to yield a set of digital data samples which, in combination, represent a data pattern characteristic of the currency denomination of said bill;
generating and storing a set of master characteristic patterns corresponding to optical scanning of original bills of each of the different currency denominations to be discriminated;
dividing at least one of (1) said data pattern and (2) said master characteristic patterns into a plurality of sections, and shifting selected ones of said sections relative to each other; and
comparing said data pattern for said scanned currency bill to each of said stored master patterns to determine the degree of correlation therebetween, and thereby to identify the denomination of said currency bill.
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Accused Products
Abstract
An improved method and apparatus for discriminating between currency bills of different denominations uses an optical sensing and correlation technique based on the sensing of bill reflectance characteristics obtained by illuminating and scanning a bill along one of its dimensions. A series of detected reflectance signals are obtained by sampling and digitally processing, under microprocessor control, the reflected light at a plurality of predefined sample points as a currency bill is moved across an illuminated strip with a preselected dimension parallel to the direction of transport of the bill. The sample data is subjected to digital processing, including a normalizing process, whereby the reflectance data represents a characteristic pattern that is unique for a given bill denomination and incorporates sufficient distinguishing features between characteristic patterns for discriminating between different currency denominations. A plurality of master characteristic patterns are generated and stored using original bills for each denomination of currency to be detected. The pattern generated by scanning a bill under test and processing the data samples is compared with each of the prestored master patterns to generate, for each comparison, a correlation number representing the extent of similarity between corresponding ones of the plurality of data samples for the compared patterns. Denomination identification is based on designating the scanned bill as belonging to the denomination corresponding to the stored master pattern for which the correlation number resulting from pattern comparison is determined to be the highest, subject to a bi-level threshold of correlation.
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Citations
24 Claims
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1. An improved method for discriminating between currency bills of different denominations comprising the acts of:
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illuminating a predetermined section of a currency bill by focusing at least one strip of light thereupon; detecting the light reflected off said illuminated section of said bill to generate an analog reflectance signal; generating relative lateral displacement between said strip of light and said bill so as to illuminate and optically scan successive sections of said bill along a predetermined dimension thereof; obtaining a series of analog reflectance signals corresponding to light reflected from each of said successive bill sections; digitizing and processing said series of analog reflectance signals to yield a set of digital data samples which, in combination, represent a data pattern characteristic of the currency denomination of said bill; generating and storing a set of master characteristic patterns corresponding to optical scanning of original bills of each of the different currency denominations to be discriminated; dividing at least one of (1) said data pattern and (2) said master characteristic patterns into a plurality of sections, and shifting selected ones of said sections relative to each other; and comparing said data pattern for said scanned currency bill to each of said stored master patterns to determine the degree of correlation therebetween, and thereby to identify the denomination of said currency bill. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An improved method for discriminating between currency bills of different denominations comprising the acts of:
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illuminating a predetermined section of a currency bill by focusing at least one strip of light thereupon; detecting the light reflected off said illuminated section of said bill to generate an analog reflectance signal; generating relative lateral displacement between said strip of light and said bill so as to illuminate and optically scan successive sections of said bill along a predetermined dimension thereof; obtaining a series of analog reflectance signals corresponding to light reflected from each of said successive bill sections; digitizing and processing said series of analog reflectance signals to yield a set of digital data samples which, in combination, represent a data pattern characteristic of the currency denomination of said bill; generating and storing a set of master characteristic patterns corresponding to optical scanning of original bills of each of the different currency denominations to be discriminated; generating and storing a set of shifted patterns by dividing each of said master characteristic patterns into a plurality of sections and by shifting selected ones of said sections relative to each other; and comparing said data pattern for said scanned currency bill to selected ones of said stored master characteristic patterns and said stored shifted patterns to determine the degree of correlation therebetween, and thereby to identify the denomination of said currency bill. - View Dependent Claims (11, 12)
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13. An improved method for discriminating between currency bills of different denominations comprising the acts of:
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illuminating a predetermined section of a currency bill with at least one strip of light; detecting the light reflected off said illuminated section of said bill to generate a reflectance signal; generating relative lateral displacement between said strip of light and said bill so as to illuminate and optically scan successive sections of said bill along a predetermined dimension thereof; obtaining a reflectance signal corresponding to light reflected from each of said successive bill sections; processing said reflectance signal to yield a set of digital data samples which, in combination, represent a data pattern characteristic of the currency denomination of said bill; retrieving from a memory a set of master characteristic patterns corresponding to optical scanning of bills of each of the different currency denominations to be discriminated; dividing at least one of (1) said data pattern and (2) said master characteristic patterns into a plurality of sections, and shifting selected ones of said sections relative to each other to generate at least one of (1) a shifted data pattern and (2) shifted master characteristic patterns; comparing at least one of (1) said shifted data pattern for said scanned currency bill to each of said stored master patterns and (2) said data pattern for said scanned bill and said shifted master characteristic patterns; and determining the denomination of said currency bill based on the act of comparing. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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22. An improved method for discriminating between currency bills of different denominations comprising the acts of:
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illuminating a predetermined section of a currency bill with at least one strip of light; detecting light reflected off said illuminated section of said bill to generate a reflectance signal; generating relative lateral displacement between said strip of light and said bill so as to illuminate and optically scan successive sections of said bill along a predetermined dimension thereof; obtaining a reflectance signal corresponding to light reflected from each of said successive bill sections; digitizing and processing said analog reflectance signal to yield a set of digital data samples which, in combination, represent a data pattern characteristic of the currency denomination of said bill; retrieving from a memory a set of master characteristic patterns corresponding to optical scanning of bills of each of the different currency denominations to be discriminated; retrieving from a memory a set of shifted master patterns which were generated by dividing each of said master characteristic patterns into a plurality of sections and by shifting selected ones of said sections relative to each other; comparing said data pattern for said scanned currency bill to selected ones of said stored master characteristic patterns and said stored shifted patterns; and determining the denomination of said currency bill based on the act of comparing. - View Dependent Claims (23, 24)
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Specification