Registration of image data
AssigneeThe McLean Hospital Corporation
InventorsLuis C. Maas, III, Blaise deB. Frederick, Perry F. Renshaw
Life of this patent
Estimating the term…
Abstract
Registration of images includes rotational and translation correction. Rotational correction includes estimating a rotational-correction angle by polar K-space cross-correlation. K-space regridding is used to rotate an image by the estimated correction angle. Translational correction is obtained by K-space phase-plane conjugation.
Claims18
A method of rotationally aligning a first image with a second image, wherein the first and second images comprise values that are uniformly spaced on a Cartesian grid, the method comprising:
- estimating a correction angle to rotationally align the first image with the second image;
- and
- rotating the first image by the estimated correction angle by using a regridding technique, wherein the regridding technique comprises:
- converting the first image from image space to k-space;
- sampling a convolution of the k-space image and a filter function at coordinates that when rotated by the estimated correction angle map onto a k-space Cartesian grid;
- assigning values to the k-space Cartesian grid based on the sampled convolution to produce a rotated k-space image;
- and
- converting the rotated k-space image into image space to produce the rotated first image.
A method of translationally aligning a first image with a second image, the method comprising:
- Fourier transforming the first and second images into k-space to produce first and second k-space images;
- computing a cross-power spectrum of the first and the second images by multiplying the Fourier transform of the first image by the complex conjugate of the Fourier transform of the second image, the cross-power spectrum having a phase profile;
- fitting the phase profile of the cross-power spectrum to a k-space phase-plane;
- multiplying the first k-space image by a k-space phase-plane that is a conjugate of the fitted k-space phase-plane;
- and
- inverse Fourier transforming the multiplied k-space image to translationally align the first image with the second image.
Dependencies are inferred from the claim text.