Method and apparatus for aligning images

Claim 2

A method according to claim 1 wherein step a) includes the steps of calculating an image coordinate transformation between one image of the received images and a previously selected image including the steps of: filtering the one image according to a selected filter characteristic; generating a measure of correlation between the filtered one image and the previously selected image; and comparing the measure of correlation to a threshold value and if the measure of correlation is less than the threshold value, selecting a different filter characteristic; and continuing to filter, correlate and compare the measure of correlation until the measure of correlation is greater than the threshold value or no further filter characteristic is available for selection; and if the measure of correlation is greater than the threshold: identifying an overlap region between one image of the source images and a previously selected image responsive to the transformation; determining measure of overlap in the overlap region; and selecting the one image to use in the image mosaic if the measure of overlap is within a predetermined range of values.

Claim 5

A system according to claim 4 wherein the selection means (716) further includes: means (836, 838, 840, 842) for calculating an image coordinate transformation between one image of the received images and a previously selected image, including: means (836, 838) for filtering the one image according to a selected one of a set of respectively different filter characteristics; means (840) for generating a measure of correlation between the filtered one image and the previously selected image; and means (842) for comparing the measure of correlation to a threshold value means, (820) responsive to the coordinate transformation, for identifying an overlap region between one image of the received images and a previously selected image; means (824) for determining a measure of overlap in the overlap region; and means (822) for selecting the one image to use in the image mosaic if the measure of overlap is within a predetermined range of values.

Claim 6

A system according to claim 7, further comprising means (103) for merging the aligned images to form the image mosaic.

Claim 7

A computer readable medium containing a program which causes a computer to align a plurality of source images, the program causing the computer to perform the steps of a) analyzing the source images to select ones of the source images to align and to form an initial alignment of the source images, and b) analyzing the selected source images to establish a coordinate system for an image mosaic; Characterized In That the step of analyzing the source images to select ones of the source images to align, selects images based on overlap among the sources images to optimize a combined match measure over all pairs of overlapping source images, and the step of analyzing the selected source images to establish a coordinate system for the image mosaic selects an initial image from the selected images to define the coordinate system, wherein the method further includes the step of: c) aligning ones of the selected source images to the coordinate system by selecting an initial image, selecting subsequent images based on at least one of (i) image content, (ii)image quality and (iii) overlap among the source images; and aligning each of the subsequent selected images to the coordinate system defined by the initial image.

Claim 8

A computer readable medium according to claim 7 wherein step a) includes the steps of: calculating an image coordinate transformation between one image of the received images and a previously selected image, including the steps of: filtering the one image according to a selected filter characteristics during each iteration; generating a measure of correlation between the filtered one image and the previously selected image; and comparing the measure of correlation to a threshold value and if the measure of correlation is less than the threshold value, selecting a different filter characteristic; and repeating the filtering, correlating and comparing the measure of correlation until the measure of correlation is greater than the threshold value or no further filter characteristic is available for selection; and if the measure of correlation is greater than the threshold: identifying an overlap region between one image of the source images and a previously selected image responsive to the coordinate transformation; determining a measure of overlap in the overlap region; and selecting the one image to use in the image mosaic if the measure of overlap is within a predetermined range of values.

Claim 9

A computer readable medium according to claim 7 or 8, the program being arranged to merge the aligned images to form the image mosaic.

Claim 10

A computer program which, when run on a suitable computer system, performs all the steps of the method of claim 4, 5 or 6.