Patent US4513441A successfully refreshed from Google Patents.
US4513441A
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Image comparison system
Assignee: Sparta Inc
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Filing: 1983-08-02
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Granted: 1985-04-23
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Expires: 2003-08-02
Abstract
Abstract Image comparison is accomplished by forming a composite image composed of a reference image and a test image. A two-dimensional image spectrum is generated from the composite image and then is whitened by setting the magnitude of every point of the two-dimensional image spectrum to a uniform level. A phase-only image of the composite image is then constructed, and values of the phase-only image exceeding a predetermined threshold are detected as an indication of the location of a difference between the reference and test images.
Inventors
- 👤 Philip D. Henshaw
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:54
CPC Classifications
G; G06; G06T; G06T5/00; G06T5/50; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/956; G01N21/95607
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
98 words
An image comparison system comprising: means for forming a composite image composed of a reference image and a test image; means for generating a two-dimensional image spectrum from said composite image; means for whitening said two-dimensional image spectrum by setting the magnitude of every point of the two-dimensional image spectrum to a uniform level; means, responsive to said means for whitening, for constructing the phase-only image of said composite image; and means for detecting a value of the phase-only image exceeding a predetermined threshold representative of the location of a difference between the said reference and test images.
Claim 2
Dependent Claim
98 words
An image comparison system comprising: means for forming a composite image composed of a reference image and a test image; means for generating a two-dimensional image spectrum from said composite image; means for whitening said two-dimensional image spectrum by setting the magnitude of every point of the two-dimensional image spectrum to a uniform level; means, responsive to said means for whitening, for constructing the phase-only image of said composite image; and means for detecting a value of the phase-only image exceeding a predetermined threshold representative of the location of a difference between the said reference and test images.
Claim 3
Dependent Claim
28 words
The image comparison system of claim 1 in which said means for forming includes an image buffer for combining said reference and test images into said composite image.
Claim 4
Dependent Claim
27 words
The image comparison system of claim 1 in which said means for forming includes a sensor for obtaining at least one of said reference and test images.
Claim 5
Dependent Claim
28 words
The image comparison system of claim 1 in which said means for forming includes a storage device for storing at least one of said reference and test images.
Claim 6
Dependent Claim
16 words
The image comparison system of claim 2 in which said image buffer includes optical storage means.
Claim 7
Dependent Claim
17 words
The image comparison system of claim 1 in which said means for generating includes a transform circuit.
Claim 8
Dependent Claim
17 words
The image comparison system of claim 6 in which said transform circuit is a Fourier transform circuit.
Claim 9
Dependent Claim
17 words
The image comparison system of claim 6 in which said transform circuit is a Hadamard transform circuit.
Claim 10
Dependent Claim
16 words
The image comparison system of claim 6 in which said mans for generating includes optical means.
Claim 11
Dependent Claim
15 words
The image comparison system of claim 9 in which said optical means includes a lens.
Claim 12
Dependent Claim
27 words
The image comparison system of claim 1 in which said means for whitening includes means for normalizing the complex components of each point of the two-dimensional image.
Claim 13
Dependent Claim
18 words
The image comparison system of claim 1 in which said means for constructing includes an inverse transform circuit.
Claim 14
Dependent Claim
19 words
The image comparison system of claim 12 in which said inverse transform circuit is an inverse Fourier transform circuit.
Claim 15
Dependent Claim
19 words
The image comparison system of claim 12 in which said inverse transform circuit is an inverse Hadamard transform circuit.
Claim 16
Dependent Claim
27 words
The image comparison system of claim 14 in which each point of said phase-only image has a phase of either zero or one hundred and eighty degrees.
Claim 17
Dependent Claim
81 words
An image comparison method comprising: forming a composite image composed of a reference image and a test image; generating a two-dimensional image spectrum from said composite image; whitening said two-dimensional image spectrum by setting the magnitude of every point of the two-dimensional image spectrum to a uniform level; constructing the phase-only image of the composite image; and detecting a value of the phase-only image exceeding a predetermined threshold representative of the location of a difference between said reference and test images.
Claim 18
Dependent Claim
81 words
An image comparison method comprising: forming a composite image composed of a reference image and a test image; generating a two-dimensional image spectrum from said composite image; whitening said two-dimensional image spectrum by setting the magnitude of every point of the two-dimensional image spectrum to a uniform level; constructing the phase-only image of the composite image; and detecting a value of the phase-only image exceeding a predetermined threshold representative of the location of a difference between said reference and test images.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-04-22 | 1988-10-22 | 1989-04-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-22 | 1992-10-22 | 1993-04-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-22 | 1996-10-22 | 1997-04-23 | $7700.00 | Window Closed / Lapsed |