Patent ID: 7809558

Claim:
A vector transformation apparatus for transforming a reference vector used in quantization of an input vector, said apparatus comprising: a first codebook that stores a plurality of first code vectors obtained by clustering vector space; a vector quantization section that acquires a number of a vector corresponding to the reference vector among the first code vectors stored in the first codebook; a second codebook that stores second code vectors obtained by performing statistical processing of a plurality of reference vectors for learning use corresponding to a plurality of input vectors for learning use per said number; a vector inverse quantization section that acquires a second code vector corresponding to the number acquired at the vector quantization section among the second code vectors stored in the second codebook; and a transformation processing section that transforms the second code vector acquired at the vector inverse quantization section to acquire a transformed reference vector, wherein: the second codebook stores differential vectors previously obtained by performing statistical processing per said number such that a total difference between the input vectors for learning use and the reference vectors for learning use becomes a minimum; and the transformation processing section adds the second code vector acquired at the vector inverse quantization section and the reference vector to acquire the transformed reference vector.