Patent US3731786A successfully refreshed from Google Patents.
Patent US4989257A successfully refreshed from Google Patents.
US4989257A
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Method and apparatus for generating size and orientation invariant shape features
Assignee: GTX Corp
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Filing: 1989-01-30
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Granted: 1991-01-29
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Expires: 2009-01-30
Abstract
Abstract A system extracts a set of size invariant, rotation invariant features from pixel data of a character and sends the set of features to a statistical decision tree to effectuate automatic recognition of a character. The set of extracted features includes a group of features that is extracted by dividing a circle bounding the character into eight rings and 24 slices and counting the number of character pixels contained in each ring and in each slice. Various Fourier transforms, autocorrelations, moment calculations, and sorting operations are performed on many of the aforementioned arrays to yield further size and orientation invariant features. The distance between the centroid of the largest hole of the character and the center of the character is computed. The ratios of the perimeters of first and second holes of the character to the outer perimeter are computed.
Inventors
- 👤 Steven L. Horowitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:57
CPC Classifications
G; G06; G06V; G06V30/00; G06V30/10; G06V30/18
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
85 words
A method of operating a computer to extract features of a character that has been electronically scanned to produce pixel data, the method comprising the steps of: (a) generating a plurality of hypothetical contiguous ring regions surrounding the character, and producing a plurality of ring variables corresponding to the respective ring regions; (b) determining the number of dark pixels of characters that lie within each ring region and setting a corresponding ring variable to that number; and (c) eliminating size information from each ring variable.
Claim 2
Independent Claim
85 words
A method of operating a computer to extract features of a character that has been electronically scanned to produce pixel data, the method comprising the steps of: (a) generating a plurality of hypothetical contiguous ring regions surrounding the character, and producing a plurality of ring variables corresponding to the respective ring regions; (b) determining the number of dark pixels of characters that lie within each ring region and setting a corresponding ring variable to that number; and (c) eliminating size information from each ring variable.
Claim 3
Dependent Claim
16 words
The method of claim 1 including computing a plurality of one-dimensional moments of the ring variables.
Claim 4
Dependent Claim
13 words
The method of claim 1 including sorting various ones of the ring variables.
Claim 5
Independent Claim
91 words
A method of operating a computer to extract features of a character that has been electronically scanned to produce pixel data, the method comprising the steps of: (a) generating a plurality of hypothetical contiguous slice regions of a circle surrounding the character, and producing a plurality of slice variables corresponding to the respective slice regions; (b) determining the number of dark pixels of characters the lie within each slice region and setting a corresponding slice variable equal to that number; and (c) eliminating size information from each of the slice variables.
Claim 6
Independent Claim
91 words
A method of operating a computer to extract features of a character that has been electronically scanned to produce pixel data, the method comprising the steps of: (a) generating a plurality of hypothetical contiguous slice regions of a circle surrounding the character, and producing a plurality of slice variables corresponding to the respective slice regions; (b) determining the number of dark pixels of characters the lie within each slice region and setting a corresponding slice variable equal to that number; and (c) eliminating size information from each of the slice variables.
Claim 7
Dependent Claim
13 words
The method of claim 4 including performing an autocorrelation on the slice variables.
Claim 8
Dependent Claim
13 words
The method of claim 4 including sorting certain ones of the slice variables.
Claim 9
Dependent Claim
19 words
The method of claim 4 including performing a real Fourier transform on the slice variables to produce harmonic coefficients.
Claim 10
Independent Claim
99 words
A system for extracting features of a character, the system comprising: (a) means for scanning the character to produce pixel data; (b) means for operating on the pixel data to generate a plurality of hypothetical contiguous slice regions of a circle surrounding the character, and means for producing a plurality of slice variables corresponding to the respective slice regions; (c) means for determining the number of dark pixels of characters that lie within each slice region and setting a corresponding slice variable equal to that number; and (d) means for eliminating size information from each of the slice variables.
Claim 11
Independent Claim
99 words
A system for extracting features of a character, the system comprising: (a) means for scanning the character to produce pixel data; (b) means for operating on the pixel data to generate a plurality of hypothetical contiguous slice regions of a circle surrounding the character, and means for producing a plurality of slice variables corresponding to the respective slice regions; (c) means for determining the number of dark pixels of characters that lie within each slice region and setting a corresponding slice variable equal to that number; and (d) means for eliminating size information from each of the slice variables.
Claim 12
Dependent Claim
15 words
The system of claim 8 including means for performing an autocorrelation on the slice variables.
Claim 13
Dependent Claim
15 words
The system of claim 8 including means for sorting certain ones of the slice variables.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-01-28 | 1994-07-30 | 1995-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-28 | 1998-07-30 | 1999-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-28 | 2002-07-30 | 2003-01-29 | $7700.00 | Window Closed / Lapsed |