ICTACT Journal on Image and Video Processing

S. Vimala ¹

Affiliations
1 Department of Computer Science, Mother Teresa Women's University, IN

Abstract

Absolute Moment Block Truncation Coding (AMBTC) is one of the lossy image compression techniques. The computational complexity involved is less and the quality of the reconstructed images is appreciable. The normal AMBTC method requires 2 bits per pixel (bpp). In this paper, two novel ideas have been incorporated as part of AMBTC method to improve the coding efficiency. Generally, the quality degrades with the reduction in the bit-rate. But in the proposed method, the quality of the reconstructed image increases with the decrease in the bit-rate. The proposed method has been tested with standard images like Lena, Barbara, Bridge, Boats and Cameraman. The results obtained are better than that of the existing AMBTC method in terms of bit-rate and the quality of the reconstructed images.

Keywords

Compression, Bit-Rate, bpp, Block, Bit-Plane, High-Mean, Low- Mean.

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S. Vimala ¹

Affiliations
1 Department of Computer Science, Mother Teresa Women’s University, IN

Abstract

Vector Quantization (VQ) is one of the Lossy Image Compression Techniques. Vector Quantization comprises of three different phases: Codebook Generation, Image Encoding and Image Decoding. The efficiency of VQ depends on the quality of the codebook. In this paper, we have proposed a novel idea for improving the quality of codebook. The codebook is populated with high detail blocks, with which the edges of the objects in an image can be preserved. The high detail blocks are identified based on the maximum and minimum pixel values of the blocks. K-Means clustering method is also used to improve the quality of the codebook. The quality (PSNR) of the reconstructed images by the proposed method is better when compared to that of few existing codebook generation techniques. Standard images are used to test the performance of the proposed method.

Keywords

Image Compression, Codebook, Training Set, High Detail Block, PSNR.

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