Patent ID: 7542597
Filing Date: 2009-06-02
Classification: G01N,G02B,G06T

Abstract:
1. Apparatus for correcting positioning and motion errors in an imaging system, comprising: means for acquiring and electronically storing at least two consecutive views of an object in a tube, said at least two views including M rows and N columns of image brightness data; a first producing means for producing a first set of modified copies of each of said at least two consecutive views by applying an alteration of brightness level to pixels having brightness levels within a specified range; a first cross-correlation means for performing a cross-correlation between said first set of modified copies with a reference pattern to produce a first cross-correlated array; a first locating means for locating and evaluating a maximum of the first cross-correlated array, where a location of said maximum determines the value of a coefficient “A”; a second producing means for producing a second set of modified copies of each of said at least two consecutive views by applying an alteration of brightness level to pixels having brightness levels within a specified range; a second cross-correlation means for performing a second cross-correlation between two of said set of modified copies to produce a second cross-correlation array; a second locating means for locating and evaluating a restricted maximum of the second cross-correlation array, said restriction being that the row or column on which said restricted maximum is located must be orthogonal to and intersect the row or column on which coefficient “A” is located, the location of said restricted maximum determining a coefficient “B;” and a motion-corrected image means for producing a motion-corrected image by shifting at least one of said at least two consecutive views by values determined by coefficient “A,” and coefficient “B,” wherein the reference pattern comprises a binary template representing the structure of the tube.