1. A pattern recognition apparatus comprising: a pattern input unit configured to input a pattern of a recognition object; a feature extraction unit configured to perform feature extraction from the input pattern to generate a feature vector; a function generation unit configured to increase the number of quantization in an order from quantization number 1 or quantization number 2 to calculate a quantization threshold of each of the quantization number, the function generation unit calculating the quantization threshold of quantization number (n+1) using a quantization threshold of quantization number n (n>=1) and generating a quantization function having a quantization threshold corresponding to quantization number S (S>n); a quantization unit configured to quantize each component of the feature vector of the input pattern using the quantization function to generate an input quantization feature vector having each of the quantized component; a dictionary feature storing unit configured to store a dictionary feature vector of the recognition object, or a quantized dictionary feature vector in which each component of the dictionary feature vector of the pattern of a recognition object is quantized; a calculation unit configured to calculate a similarity between the input quantization feature vector and the dictionary feature vector, or a similarity between the input quantization feature vector and the quantized dictionary feature vector; and a determination unit configured to recognize the recognition object based on the similarity.