METHOD, APPARATUS AND PROGRAM FOR TRANSFORMING INTO BINARY DATA

Data set is transformed into a plurality of items of K-bit-long binary data, using, as each of K number hash functions that transforms the data into a binary representation based on a value of projection of the data point on a projection vector. A hash function parameter optimization section finds a hash value, using a continuous valued hash function including, as a variable, the projection of data point on a projection vector, and stores continuous valued learning data for binary transformation, and derives optimized parameter(s) of the hash function that minimizes a cost function, defined based on a distance of the data point and on a distance of the learning data for binary transformation.