RETRIEVAL DEVICE AND PROGRAM FOR RETRIEVING HIGH DIMENSIONAL FEATURE VECTOR WITH SMALL AMOUNT OF CODEBOOK INFORMATION

PROBLEM TO BE SOLVED: To provide a retrieval device etc. for retrieving a feature vector similar to a query feature vector from a set of high dimensional feature vectors, with a small amount of codebook information.SOLUTION: A learning unit in a retrieval device includes residual codebook generation means that generates an n number of residual clusters by deriving residual vectors fbetween representative vectors fand learned vectors f (S71), generates sets of residual partial vectors Rn,t by dividing the vectors finto T pieces (S72), assigns label values m in a residual codebook identifier table T[n][t] (S73), generates an m-th residual codebook using all sets of residual partial vectors Rn,t to which the values m are assigned, for each value m (S74), and updates the table T[n][t] using an m'-th residual codebook which results in the smallest quantization error when quantizing using each of the m number of residual codebooks (S75).