Fig. 2

An example of distance-preserving hashing with k = 4, i.e., four Cosine LSH functions are applied to each feature vector. w denotes the biometric feature vector, and \(h(\cdot )\) denotes the Cosine LSH. The “green-colored” feature vector is closer to the “blue” one than the “orange” one. After the distance-preserving hashing, the left result is still closer to the middle result than the right result in Hamming space