PURPOSE: To obtain a pattern recognizing method which can recognize the similarity of a pattern without being affected by the shift of the pattern and variation of illumination light, vary the detection sensitivity for the similarity of the pattern, and find the similarity of an object pattern represented with numerals that can not be compared directly.

CONSTITUTION: The similarity is calculated by projecting a test pattern vector on a linear partial space formed with a basic pattern vector at a reference position and plural pattern vectors obtained by moving the basic pattern vector. An image after a normalizing filter is used is regarded as a pattern vector. Further, the sensitivity of recognition detection is varied by adjusting the dimensions of the pattern vector. For the object which is represented with the numerals which can not be compared directly, its data are converted into an image as a pattern vector.