Patent ID: 9183460
Filing Date: 2015-11-10
Classification: G06K

Abstract:
1. A computer-implemented method performed by data processing apparatus, the method comprising: determining, for each of a first image and a second image, each of the first and second image comprising respective image data depicting visual content, a respective set of local image feature descriptions, each local image feature description describing a local image feature detected in the image and the location of the local image feature within the image; determining one or more unmatched regions of the images that include unmatched image features and that correspond to one or more same respective regions in both the first image and the second image; determining, for each of the one or more unmatched regions of the images, a modification measure based on the image data corresponding to the unmatched region in the first image and the image data corresponding to the unmatched region in the second image; and determining that the second image is a modification of the first image when one of the modification measures meets a modification measure threshold; wherein: determining one or more unmatched regions of the images comprises: determining, from the respective sets of local image feature descriptions, unmatched local image features, each unmatched local image feature being a local image feature in one of the respective sets that does not have a corresponding matching local image feature in the other set of the respective sets; and determining, from the unmatched local image features, one or more unmatched regions of the images that include unmatched image features and that correspond to one or more same respective regions in both the first image and the second image.