Adaptive Coding of Images Using DCT and Classification of Blocks for Segmentation

Johelden Campos Bezerra, Evaldo Gonçalves Pelaes

DOI: 10.14209/its.2002.521

Evento: 2002 International Telecommunications Symposium (ITS2002)

Keywords:

Abstract

"This article propose a technique of adaptive coding of images, implemented from the classification of the size blocks MxM, with the aid of the technique of segmentation of images for the detection of discontinuities in the image, generating K classes with different levels of discontinuities, containing, each one, a variable number of blocks by class. The bits allocation table in this method is determined by the log-variance rule, using only one block of size K of sub-blocks MxM, each one belonging to a class. The method is applied using the DCT, with the uniform, laplacian and gaussian quantization of Lloyd-Max, and with blocks of size 8x8. The proposed method was applied in several images, like Lena, Barbara, Baboon, Goldhill, presenting a medium gain of 4 dB in the SNR at rate 1 bpp, and a maximum gain of 9,04 dB at rate 5 bpp, when compared with the method of images coding using DCT without classification."

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