1. A pattern recognition apparatus comprising: an image pickup section for picking up an image of patterns; a pretreated circuit for converting an output signal of said image pickup section into image pattern data consisting of binary-coded signals; a pattern memory circuit having N.times.M addresses for storing N.times.M bits of said image pattern data, where M and N are integers; a reference pattern memory circuit having at least n.times.m addresses for storing reference pattern data consisting of n.times.m bits of a reference pattern, where m and n are integers smaller than M and N respectively; a first correlation calculating circuit for calculating first correlations between sub-images each consisting of n.times.m bits of said image pattern data and said reference pattern data, respectively, each of said first correlations being expressed as R(X), where X is a variable factor representing a memory region storing one of said image pattern data sub-images in said pattern memory circuit; and a second correlation calculating means for recognizing the position of a pattern most identical to said reference pattern, by emphasizing the maximum value of said first correlations by converting each of said first correlations R(X) into a second correlation expressed as [R(X)-R(X-.alpha.)]-[R(X+.alpha.).times.R(X)], where .alpha. is a predetermined value determined in accordance with the size of said reference pattern data.