Patent ID: 7082224
Filing Date: 2006-07-25
Classification: G06K,G06T

Abstract:
1. An apparatus for calculating a normalized correlation coefficient used as a similarity evaluation measure by using image data values of pixels in a template image and image data values of pixels in a subimage, included in a search image, corresponding to the template image, comprising: a memory for storing image data values of pixels in the search image; sum calculating means for calculating a sum of image data values of pixels in a first rectangular region, defined by a plurality of rows and columns, in the search image by using a sum, obtained prior to the sum of image data values of pixels in the first rectangular region, of image data values of pixels in a second rectangular region having a partial region in common with the first rectangular region, and using a difference between image data values of pixels in a region, included in the first rectangular region, other than the partial region and image data values of pixels in a region, included in the second rectangular region, other than the partial region, the difference being calculated by using a first image data value of a pixel which is adjacent to the uppermost pixel in a first column of the first rectangular region positioned on one side thereof on the upper side of the uppermost pixel, a second image data value of the lowermost pixel in the first column, a third image data value of a pixel which is adjacent to the uppermost pixel in a column, positioned on the opposite side to the first column, of the second rectangular region on the upper side of the uppermost pixel, the third image data value having been read out prior to the sum of image data values of pixels in the first rectangular region, and a fourth image data value of the lowermost pixel in the second column of the second rectangular region; and normalized correlation coefficient calculating means for calculating a normalized correlation coefficient on the basis of a sum of image data values of pixels in the template image and a sum of image data values of pixels in the first rectangular region in the search image.