Double-Coding Density Sensitive Hashing

This paper proposes a double-coding density sensitive hashing (DCDSH) method. DCDSH accomplishes approximate nearest neighbor (ANN) search tasks based on its double coding scheme. First, DCDSH generates real-valued hash codes by projecting objects along the principle hyper-planes. These hyper-planes are determined by principle distributions and geometric structures of data set. Second, DCDSH derives binary hash codes based on these real-valued hash codes. Real-valued hash codes can avoid undesirable partition of objects in low density areas and effectively improve representation capability and discriminating power. Binary codes contribute to query speed owing to the low complexity for computing hamming distance. DCDSH integrates the advantages of these two kinds of hash codes. Experimental results on large scale high dimensional data show that the proposed DCDSH exhibits superior performance compared to several state-of-the-art hashing methods.