An efficient bitmap indexing method for similarity search in high dimensional multimedia databases

The paper proposes a new indexing mechanism for similarity search in high-dimensional multimedia database; it quickly filters out irrelevant objects using a bitmap index, in which the characteristic of each object is approximated as a bit-string. The bits in a bitstring that are set to '1' denote the representative dimensions of an object that their attribute values are a relatively larger value than others. Since two objects are dissimilar if their representative dimensions are so much different, the degree of dissimilarity can be computed easily by XORing the bit-strings of two objects and counting the number of '1' s in the resulting bit-string. Experimental results with more than 100,000 images show that a remarkable speed-up can be obtained with the proposed indexing method compared to the VA-file and linear scan method because of the simple XORing operation in the filtering process, although there is some loss in search accuracy.