US6178271B1
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Methods and systems for registering image data
Assignee: McLean Hospital
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Filing: 1998-12-15
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Granted: 2001-01-23
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Expires: 2018-12-15
Abstract
Abstract Methods and systems for estimating a correction angle that rotationally aligns a first polar centered image with a second polar centered image, wherein the first and second polar centered images includes values on a polar grid having evenly spaced polar angle coordinates for each of at least one radial distance coordinate, include the following steps: calculating a polar cross-power spectrum for the first and second polar centered images, the polar cross-power spectrum comprising a phase profile having at least polar angular frequency coordinates; and fitting a linear function of the angular frequency coordinate to the phase profile of the polar cross-power spectrum to determine the correction angle.
Inventors
- 👤 Luis C. Maas, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:03
CPC Classifications
G; G06; G06T; G06T3/00; G06T3/02; G06T7/00; G06T7/30; G06T7/37; G06V; G06V10/00; G06V10/20; G06V10/24; G06T2207/00; G06T2207/10; G06T2207/10072; G06T2207/10088
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
126 words
A method for rotationally aligning a first image with a second image, the method comprising: providing first and second polar centered images related to the first and second images, wherein the first and second polar centered images comprise values on a polar grid having evenly spaced polar angle coordinates for each of at least one radial distance coordinate; calculating a polar cross-power spectrum for the first and second polar centered images, the polar cross-power spectrum comprising a phase profile having at least polar angular frequency coordinates; fitting a linear function of the angular frequency coordinate to the phase profile of the polar cross-power spectrum to determine a correction angle; and rotating the first image by the correction angle to rotationally align the first and second images.
Claim 2
Independent Claim
126 words
A method for rotationally aligning a first image with a second image, the method comprising: providing first and second polar centered images related to the first and second images, wherein the first and second polar centered images comprise values on a polar grid having evenly spaced polar angle coordinates for each of at least one radial distance coordinate; calculating a polar cross-power spectrum for the first and second polar centered images, the polar cross-power spectrum comprising a phase profile having at least polar angular frequency coordinates; fitting a linear function of the angular frequency coordinate to the phase profile of the polar cross-power spectrum to determine a correction angle; and rotating the first image by the correction angle to rotationally align the first and second images.
Claim 3
Dependent Claim
133 words
The method of claim 1 , wherein the first and second images each comprise values on an evenly spaced Cartesian grid, and wherein providing the first and second polar centered images comprises: Fourier transforming the first and second images to produce first and second k-space images, wherein values of the first and second k-space images comprise complex values on an evenly spaced k-space Cartesian grid; generating first and second centered images from the first and second k-space images with a mapping function that maps the absolute value of each complex value in the first and second k-space images to generate a corresponding value in the first and second centered images; and converting the first and second centered images from Cartesian coordinates to polar coordinates to produce the first and second polar centered images.
Claim 4
Dependent Claim
37 words
The method of claim 2 , wherein the mapping function squares the absolute value of each complex value in the first and second k-space image to produce the corresponding value in the first and second centered images.
Claim 5
Dependent Claim
38 words
The method of claim 2 , wherein the mapping function leaves the absolute value of each complex value in the first and second k-space image unchanged to produce the corresponding value in the first and second centered images.
Claim 6
Dependent Claim
33 words
The method of claim 2 , wherein converting comprises logarithmically scaling the first and second centered images with respect to a radial frequency component to produce the first and second polar centered images.
Claim 7
Dependent Claim
55 words
The method of claim 1 , wherein the first and second images are centered images that each comprise values on a Cartesian grid, and wherein providing the first and second polar centered images comprises: converting the first and second centered images from Cartesian coordinates to polar coordinates to produce first and second polar centered images.
Claim 8
Dependent Claim
20 words
The method of claim 1 , wherein the first and second images are the first and second polar centered images.
Claim 9
Dependent Claim
93 words
The method of claim 2 , wherein rotating comprises: converting the first image into polar coordinates to produce a first polar image; Fourier transforming the first polar image with respect to the polar angle coordinate; multiplying the Fourier transformed first polar image by a complex exponential having the linear function as an argument; inverse Fourier transforming the multiplied Fourier transformed first polar image with respect to the polar angle coordinate to produce a rotated first polar image; and converting the rotated first polar image into Cartesian coordinates to produce a rotated first image.
Claim 10
Dependent Claim
29 words
The method of claim 8 , wherein the complex exponential is exp(−ik θ Δ), where k θ is the polar angular frequency coordinate and Δ is the correction angle.
Claim 11
Dependent Claim
25 words
The method of claim 1 , wherein the polar cross-power spectrum and phase profile are matrices having polar angular frequency coordinates and radial distance coordinates.
Claim 12
Dependent Claim
23 words
The method of claim 1 , wherein the polar cross-power spectrum and the phase profile are vectors having only polar angular frequency coordinates.
Claim 13
Dependent Claim
29 words
The method of claim 1 , wherein the linear function is k θ Δ where k θ is the polar angular frequency coordinate and Δ is the correction angle.
Claim 14
Dependent Claim
23 words
The method of claim 1 , wherein fitting comprises unwrapping values for the phase profile based on an estimate of the correction angle.
Claim 15
Dependent Claim
52 words
The method of claim 13 , wherein fitting further comprises determining the estimate by fitting a subset of values for the phase profile to the linear function, wherein the subset of values corresponds to angular frequencies k θ that are less than 2π divided by an upper limit for the correction angle.
Claim 16
Dependent Claim
59 words
The method of claim 1 , wherein fitting comprises determining a first estimate Δ (1) for the correction angle based by fitting a subset of values for the phase profile to the linear function, wherein the subset of values corresponds to angular frequencies k θ that are less than 2π divided by an upper limit for the correction angle.
Claim 17
Dependent Claim
44 words
The method of claim 15 , wherein fitting further comprises determining a correction to the first estimate Δ (1) by calculating a residual phase equal to the phase profile subtracted by k θ Δ (1) and fitting the residual phase to another linear function.
Claim 18
Dependent Claim
14 words
The method of claim 1 , wherein fitting comprises using a least squares regression.
Claim 19
Dependent Claim
42 words
A method of aligning a first image with a second image, the method comprising: rotationally aligning the first image with the second image using the method of claim 2 ; and translationally aligning the rotationally aligned first image with the second image.
Claim 20
Independent Claim
120 words
A method for aligning a first image with a second image, wherein the first and second images each comprise values on a Cartesian grid, the method comprising: calculating power spectra for the first and second images; converting the power spectra from Cartesian coordinates to polar coordinates; calculating a polar cross-power spectrum for the polar power spectra, the polar cross-power spectrum comprising a phase profile having at least polar angular frequency coordinates; fitting a linear function of the polar angular frequency coordinate to the phase profile of the polar cross-power spectrum to determine a correction angle that rotationally aligns the power spectra; rotating the first image by the correction angle; and translationally aligning the rotated first image with the second image.
Claim 21
Independent Claim
120 words
A method for aligning a first image with a second image, wherein the first and second images each comprise values on a Cartesian grid, the method comprising: calculating power spectra for the first and second images; converting the power spectra from Cartesian coordinates to polar coordinates; calculating a polar cross-power spectrum for the polar power spectra, the polar cross-power spectrum comprising a phase profile having at least polar angular frequency coordinates; fitting a linear function of the polar angular frequency coordinate to the phase profile of the polar cross-power spectrum to determine a correction angle that rotationally aligns the power spectra; rotating the first image by the correction angle; and translationally aligning the rotated first image with the second image.
Claim 22
Dependent Claim
21 words
Apparatus comprising a computer readable medium storing a program that causes a processor to perform the steps of claim 1 .
Claim 23
Dependent Claim
21 words
Apparatus comprising a computer readable medium storing a program that causes a processor to perform the steps of claim 2 .
Claim 24
Dependent Claim
21 words
Apparatus comprising a computer readable medium storing a program that causes a processor to perform the steps of claim 19 .
Claim 25
Dependent Claim
61 words
A system for processing a series of images, the system comprising: an input port that receives the series of images; a data storage device, operably coupled with the input port, that stores the images; and a processor, operably coupled with the input port and data storage device, that registers the images; wherein the processor performs the steps of claim 1 .
Claim 26
Dependent Claim
61 words
A system for processing a series of images, the system comprising: an input port that receives the series of images; a data storage device, operably coupled with the input port, that stores the images; and a processor, operably coupled with the input port and data storage device, that registers the images; wherein the processor performs the steps of claim 2 .
Claim 27
Dependent Claim
61 words
A system for processing a series of images, the system comprising: an input port that receives the series of images; a data storage device, operably coupled with the input port, that stores the images; and a processor, operably coupled with the input port and data storage device, that registers the images; wherein the processor performs the steps of claim 19 .
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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) | 2004-01-23 | 2004-07-24 | 2005-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-01-23 | 2008-07-24 | 2009-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-01-23 | 2012-07-24 | 2013-01-23 | $7700.00 | Window Closed / Lapsed |