Generation of Codebooks by Using Self-Organizing Maps and Its Application to Enlargement of Various Types of Images

Abstract

We propose a new image enlargement method employing a codebook and a fuzzy similarity measure in order to realize both of smoothing and sharpening in various types of image enlargement. In the proposed method, codes (vectors) in codebooks, which are generated by Self-Organizing Maps, are regarded as fuzzy if-then rules, and unknown pixel values in the image are estimated by a fuzzy inference. In this inference, fuzzy similarities between the input and the antecedent parts of the rules are calculated, then the estimation is achieved by taking a center of gravity of the consequents. In this paper, we apply this technique, with a codebook of Lena, to various standard digital images except Lena. The experimental results show that the proposed method is superior to other image enlargement techniques.