×

Hash-based image identification

  • US 7,761,466 B1
  • Filed: 07/30/2007
  • Issued: 07/20/2010
  • Est. Priority Date: 07/30/2007
  • Status: Expired due to Fees
First Claim
Patent Images

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.

View all claims
  • 8 Assignments
Timeline View
Assignment View
    ×
    ×