Image search apparatus and method

An image search apparatus comprising:

• input means for inputting an image;
• power spectrum computation means for computing a two-dimensional power spectrum of the inputted image by computing a two-dimensional Fourier transform of the inputted image;
• standard deviation matrix generation means for segmenting the two-dimensional power spectrum computed by said power spectrum computation means into a plurality of blocks on a two-dimensional coordinate system, computing standard deviations of power spectrum components in units of blocks, and generating a matrix of the generated standard deviations;
• feature amount computation means for computing sums of the standard deviations as feature amounts in units of directions by making the matrix generated by said standard deviation matrix generation means using predetermined mask patterns which are prepared in advance in units of directions of interest and correspond to a pattern of the matrix;
• feature determination means for determining a directionality of the inputted image on the basis of the feature amounts computed by said feature amount computation means;
• storage means for classifying and storing the inputted image and the feature amounts computed by said feature amount computation means on the basis of the directionality determination result of said feature determination means;
• and
• image search means for searching for a similar image to that of the inputted image in said storage means on the basis of the feature amounts and determination result stored in said storage means.