Patent ID: 7761466
Filing Date: 2010-07-20
Classification: G06F,G06K

Abstract:
1. A method of identifying target images, comprising: obtaining keypoints at different locations within a sample image and descriptor vectors for the keypoints, the descriptor vectors describing local image information around the keypoints, where each descriptor vector is an n-dimensional array; generating features based on hashes of data vectors that include at least one of the descriptor vectors, where each feature is a tuple comprising a hash value of each data vector and a quantization function mapping an orientation of each keypoint to a range of integers; searching for the features in an image-feature database; and retrieving and providing target images based on a number of the features for which corresponding features exist in individual database images whose features are represented in the image-feature database, wherein the hashes are performed using a hash function for which a probability that the hash of an arbitrary first vector corresponds to the hash of an arbitrary second vector is a function of an angle between the first vector and the second vector, wherein the hash function generates a characteristic data string from a data vector larger than the characteristic data string, wherein the arbitrary first vector is a first descriptor vector, and the arbitrary second vector is a second descriptor vector, and wherein each feature corresponds to two keypoints, and each feature is a tuple; wherein each tuple comprises: a hash value of a first descriptor vector for a first keypoint, a hash value of a second descriptor vector for a second keypoint, a first quantization function mapping an orientation of the first keypoint in relation to the second keypoint to a range of integers, and a second quantization function mapping an orientation of the second keypoint in relation to the first keypoint to the range of integers.