US4941192A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for recognizing pattern of gray level image
Assignee: Hitachi Ltd
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Filing: 1988-04-19
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Granted: 1990-07-10
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Expires: 2008-04-19
Abstract
Abstract In a method of recognizing a pattern of a gray level image the image to be processed is subjected to a normalization process, local gray level feature parameters are extracted from the normalized image at its sampling points, and the pattern is identified by using the extracted feature parameters in accordance with a predetermined recognition procedure. An apparatus for recognizing a pattern of a gray level includes a memory for storing a gray level image having several brightness tone levels, a normalization circuit for normalizing the brightness of the gray level image to be processed, an extraction circuit for extracting local gray level feature parameters from the obtained normality image at specific points, and a recognition circuit for identifying the pattern by using the feature parameters in accordance with a predetermined.
Inventors
- 👤 Tadaaki Mishima
- 👤 Morio Kanasaki
- 👤 Masao Takatoo
- 👤 Hideo Ota
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:51
CPC Classifications
G; G06; G06V; G06V10/00; G06V10/20; G06V30/00; G06V30/10; G06V30/18; G06V30/18086; G06V30/18095
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
54 words
A method of recognizing a pattern of a gray level image comprising the steps of: normalizing a gray level image to be processed; extracting local feature parameters of said normalized gray level image at predetermined sampling points; and identifying a pattern by using said extracted feature parameters in accordance with a predetermined recognition procedure.
Claim 2
Independent Claim
54 words
A method of recognizing a pattern of a gray level image comprising the steps of: normalizing a gray level image to be processed; extracting local feature parameters of said normalized gray level image at predetermined sampling points; and identifying a pattern by using said extracted feature parameters in accordance with a predetermined recognition procedure.
Claim 3
Dependent Claim
32 words
A method according to claim 1, wherein said local gray level feature parameters are obtained at specific positions of said normalized gray level image through a multiplication/addition calculation by a local filter.
Claim 4
Dependent Claim
35 words
A method according to claim 1, wherein said local gray level feature parameters are the sum, average or dispersion values of densities at specific positions of said normalized gray level image within a local area.
Claim 5
Dependent Claim
47 words
A method according to claim 1, wherein said local gray level feature parameters are differences between two average densities, one average density being darker than said threshold value, said two average densities being obtained at specific positions of said normalized gray level image within a local area.
Claim 6
Dependent Claim
53 words
A method according to claim 1, wherein said local gray level feature parameters are obtained at specific positions of said normalized gray level image, said specific positions used in obtaining said local gray level feature parameters being determined by using a pattern to be recognized, said pattern being binarized prior to said determination.
Claim 7
Dependent Claim
26 words
A method according to claim 2, wherein said local gray level parameters at said specific positions are maximum values among values obtained near said specific positions.
Claim 8
Dependent Claim
26 words
A method according to claim 3, wherein said local gray level parameters at said specific positions are maximum values among values obtained near said specific positions.
Claim 9
Dependent Claim
26 words
A method according to claim 4, wherein said local gray level parameters at said specific positions are maximum values among values obtained near said specific positions.
Claim 10
Dependent Claim
37 words
A method according to claim 2, wherein the coefficients of said local filter for performing said multiplication/addition calculation are set so as to match changes in brightness of a character line of said pattern to be processed.
Claim 11
Independent Claim
75 words
An apparatus for recognizing a pattern of a gray level image comprising; a memory storing a gray level image having a change in brightness; a normalization circuit normalizing the brightness of said gray level image to be processed; an extraction circuit extracting local gray level feature parameters at specific positions of said normalized gray level image; and a recognition circuit identifying a pattern by using said feature parameters in accordance with a predetermined recognition procedure.
Claim 12
Independent Claim
75 words
An apparatus for recognizing a pattern of a gray level image comprising; a memory storing a gray level image having a change in brightness; a normalization circuit normalizing the brightness of said gray level image to be processed; an extraction circuit extracting local gray level feature parameters at specific positions of said normalized gray level image; and a recognition circuit identifying a pattern by using said feature parameters in accordance with a predetermined recognition procedure.
Claim 13
Dependent Claim
51 words
An apparatus according to claim 10, wherein said gray level image normalization circuit comprises a local maximum filter circuit, a local minimum filter circuit, and an inter-image calculation circuit obtaining a difference image between an image obtained by said local maximum and minimum filter circuits and an image to be processed.
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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) | 1993-07-09 | 1994-01-08 | 1994-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-09 | 1998-01-08 | 1998-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-09 | 2002-01-08 | 2002-07-10 | $7700.00 | Window Closed / Lapsed |