Patent US 9,405,993

Image processing includes dividing the plurality of images into a plurality of groups wherein images in the same group share the same main color; extracting a color feature vector (CFV) of each image in the plurality of groups; subdividing images in each of the plurality of groups into a plurality of subgroups using a clustering technique according to a distance between the CFVs of the images in the group to establish an image signature tree; searching among the plurality of subgroups for a result-subgroup having the same main color as the main color of a given image and containing an image whose CFV has the shortest distance from the CFV of the given image; comparing the CFV of the given image with the CFVs in the result group; and identifying a near-duplicate image from the result group that meets a preset near-duplicate image determining condition.