INDEXING METHOD AND RETRIEVING METHOD OF CHARACTERISTIC VECTOR SPACE

摘要

PROBLEM TO BE SOLVED: To provide a method for indexing a high-dimensional characteristic vector space, and a method for retrieving a characteristic vector having a characteristic similar to an inquiry vector at a high speed in the vector space indexed by this indexing method. SOLUTION: This method is characterized by including (a) a stage for dividing the characteristic vector space into plural approximate areas, (b) a stage for discriminating density of a selected approximate area by selecting an optional approximate area, and (c) a stage for indexing the characteristic vector space as one specific node belonging to a slave node of a wooden data structure together with the other sparse approximate area for separating a corresponding approximate area by a distance shorter than a prescribed distance when the approximate area is discriminated as a sparse approximate area in the stage (b).