1. A face recognition apparatus adapted for recognizing an input face image based on one or more registered face images, comprising: a face image inputting unit that inputs the face image to be recognized; a Gabor filter application unit, implemented via a processor, that calculates convolution of a pixel value at each feature value extraction position of the input image and coefficients of a Gabor filter, the coefficients of the Gabor filter being defined by a Gabor function representing a spatial characteristic using a Gaussian function representing a window and a sine function or a cosine function representing a frequency response, for each of a predetermined set of frequency values and for each of a predetermined set of angles of a response function of the Gabor filter thereby determining a Gabor jet having as many scalar values as there are Gabor filters; a similarity calculation unit that calculates a similarity between a Gabor jet at each feature value extraction position of the input face image and a Gabor jet of a registered face image, and that determines a similarity vector whose elements are given by values indicating similarity at respective feature value extraction positions; and an identification determination unit that determines when the input face image is identical to the registered face image based on the similarity vector, the Gabor filter application unit including a filter window data ROM that stores values of the filter window determined by calculating the Gaussian function, sine data ROMs that store values of the response function determined by calculating the sine function for the respective angles, cosine data ROMs that store values of the response function determined by calculating the cosine function for the respective angles, and a Gabor filter coefficient calculation unit that calculates coefficients of the Gabor filter by multiplying a value read from the filter window data ROM and the values read from the sine data ROMs and the cosine data ROMs, and a convolution of the input face image and a convolution of Gabor filter coefficients calculated by the Gabor filter coefficient calculation unit.