Patent ID: 8103097

Claim:
A method performed by one or more processes executing on a machine, the method comprising: accessing a first color image having values in RGB channels for each of a plurality of points within the first color image, wherein the RGB channels comprise a red (R) channel, a green (G) channel, and a blue (B) channel; generating a first pseudo-color image at least in part by applying histogram-equalization transformations to the values in the RGB channels of the first color image independently of the values in the other RGB channels of the first color image, such that the generated first pseudo-color image is invariant to both (i) illumination conditions of a scene depicted in the first color image and (ii) response of an imaging device that acquired the first color image; generating a three-dimensional RGB histogram of the first pseudo-color image; identifying a match to the first color image at least in part by accessing a second color image having values in the RGB channels for each of a plurality of points within the second color image; generating a second pseudo-color image at least in part by applying histogram-equalization transformations to the values in the RGB channels of the second color image independently of the values in the other RGB channels of the second color image, such that the generated second pseudo-color image is invariant to both (i′) illumination conditions of another scene depicted in the second color image and (ii′) response of another imaging device that acquired the second color image; generating a three-dimensional RGB histogram of the second pseudo-color image comparing the RGB histogram of the first pseudo-color image with the RGB histogram of the second pseudo-color image to determine whether the RGB histograms of the first and second pseudo-color images are similar; in response to determining that the RGB histogram of the second pseudo-color image is similar to the RGB histogram of the first pseudo-color image, identifying the second color image as the match to the first color image; and in response to determining that the RGB histogram of the second pseudo-color image is dissimilar to the RGB histogram of the first pseudo-color image, identifying the second color image as a mismatch to the first color image.