1. A feature value extraction apparatus, comprising: a processor; a memory; an image receiver that receives an input of an image; a converted image generator that converts the input image into a plurality of converted images for extracting a feature value of the input image; a feature value generation pattern holding storage that stores a feature value generation pattern that includes a plurality of comparison pairs of unit positions for comparing unit values in a unit array in which units, each of which includes at least one pixel, are arranged; and a feature value extractor that compares the unit values corresponding to the comparison pairs through referring to the feature value generation pattern with respect to each of the plurality of converted images, and extracts the feature value for each of the plurality of converted images, wherein the feature values for the plurality of converted images are connected with each other to obtain the feature value of the input image.