engleski

Picture Quality Measurements in Wavelet Compression System

The two-dimensional discrete wavelet transform (DWT) has become a standard tool in image compression applications because of their data reduction capabilities. In wavelet compression system the entire image is transformed and compressed as a single data object rather than block by block as in Discrete Cosine Transform (DCT) based compression system. It allows a uniform distribution of compression error across the entire image. DWT can provide better image quality than DCT especially on higher compression ratios. In this paper the extent to which the quality of image is degraded by process of wavelet compression and decompression is considered. Image quality is measured objectively using peak signal-to-noise ratio (PSNR) and subjectively using perceived image quality. The effects of different wavelet functions, image contents, image resolutions and compression ratios are assessed. The comparison with DCT based compression system for different image contents and compression ratios is presented.

Discrete Wavelet Transform; Image Quality; Compression

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