Patent ID: 7430319

Claim:
An image collating apparatus which collates a reference image as a criterion with a check image obtained by subjecting the reference image to predetermined processing, comprising: a reference image obtaining unit that obtains the reference image as a printing object before the printing object is printed on a medium; a first accumulation unit that sets a plurality of predetermined paths in the reference image, and accumulates pixel values in the paths with respect to the plurality of paths to obtain a projected waveform or histogram of the reference image; a check image obtaining unit that obtains the check image as the printing object on the medium after the printing object is printed on the medium; a second accumulation unit that sets the plurality of predetermined paths in the check image, and accumulates the pixel values in the paths with respect to the plurality of paths to obtain the projected waveform or histogram of the check image; a first information extraction unit that extracts information of a characteristic value as reference characteristic value information from the projected waveform or histogram of the reference image; a second information extraction unit that extracts information of the characteristic value as check characteristic value information from the projected waveform or histogram of the check image; and a collation unit that collates the reference image with the check image based on the reference characteristic value information and check characteristic value information, wherein the reference characteristic value information is information indicating a position on the projected waveform or histogram where a change of the accumulated value is characteristic in the reference projected waveform or histogram, the check characteristic value information is information indicating a position on the projected waveform or histogram where the change of the accumulated value is characteristic in the check projected waveform or histogram, the collation unit collates the reference image with the check image so as to obtain similarity based on the reference characteristic value information and check characteristic value information, the reference characteristic value information is compared with the check characteristic value information to obtain a similarity transformation parameter including a parallel displacement amount, and the similarity transformation parameter is used to measure the similarity between the reference image and check image, and to obtain the similarity transformation parameter, a predetermined range of scaling margin is set to at least one amount included in the similarity transformation parameter, and the similarity transformation parameter is determined from the range of scaling margin.