Patent ID: 8213723

Claim:
A method for determining near-duplicate images, the method comprising: receiving a search request comprising at least one term associated with a content item appearing in at least one image; identifying a plurality of images in response to the search request; performing a Fourier-Mellin Transform on each of the identified plurality of images; for each image of the identified plurality of images, generating a signature based on the Fourier-Mellin transform comprising: converting the image to a gray-scale; if needed, resizing the gray-scale to a fixed size; transforming the gray scale to a log-polar representation using a center point as a reference point; and performing median thresholding including: reordering a first window of the image by a first squared dimensional vector; finding a median value of the vector; creating a binary representation of the median value of the vector, creating a second squared binary representation of a second window of the image; and concatenating the first binary representation and second binary representation to generate the signature; comparing the signature of a first of the plurality of images to at least the signature of at least a second of the plurality of images; determining that at least the second image is a near-duplicate of the first image based on the comparing of the signatures; and generating a result set of images in response to the search request, the result set including the first image while excluding at least the second image based on the second image being a near-duplicate of the first image.