1. A pattern recognition apparatus for identifying the category of an input pattern from various categories of value patterns stored in the apparatus comprising: a vector generating means for converting an input pattern signal to an input vector representing the characteristics of the input pattern; a dictionary means for storing a plurality of reference vectors for each of said various categories, including a first memory means for storing a plurality of predetermined first reference vectors for each of said categories, said first reference vectors representative of features common to said categories, and a second memory means for storing a plurality of subsequently determined second reference vectors for each of said categories, said second reference vectors representative of features particular to said categories, said second reference vectors being mutually exclusive of said first reference vectors; a reference vector generating means for generating said second reference vectors from the input vector and for storing them in said second memory means, said reference vector generating means generating said second reference vectors by subtracting from the input vector a vector having components corresponding to the angles between the input vector and each of said first reference vectors; a similarity calculating means for calculating the similarities between said input vector and reference vectors stored in said dictionary means for each of said categories; and a comparing means for comparing the similarities calculated for each of said categories and for identifying the category of the input pattern.