SIMILAR-IMAGE RETRIEVING APPARATUS, SIMILAR-IMAGE RETRIEVING METHOD AND PROGRAM STORAGE MEDIUM

A similar-image retrieving apparatus and a similar-image retrieving method allow data amount to be reduced by digitizing feature quantities of external shapes of islands extracted from images, and also allow shape comparison to be achieved by simple calculation of the digitized feature quantities. Thus, the apparatus and the method are capable of practical retrieval of similar images. A feature quantity extracting section 2 extracts an external shape of an island from image data, and determines coefficients by Fourier series expansion of point strings of edge pixels of the external shape, thereby extracting the coefficients as feature quantities of the external shape of the island. Based on the feature quantities of a key image and the feature quantities of comparative images extracted in this way by the feature quantity extracting section 2, similarities between the key image and the comparative images are calculated by a similarity calculating section 6.