| Summary: | 碩士 === 國立交通大學 === 電機與控制工程系 === 88 === The zerotree structure based on wavelet transform was first introduced by Shapiro in his work of embedded zerotree wavelet(EZW) and later improved by Said and Pearlman in their work of set partitioning in hierarchical trees (SPIHT) \cite{SPIHT}. This technique not only was competitive in performance with the most complex techniques, but was extremely fast in execution and produced an embedded bit stream.
We develop 2 SPIHT based image coders: 1) image coder incorporating perceptual models, 2) image coder with dual SNR and spatial scalabilities. The perceptual models are used to improve the perceptual quality at the same bit rate while scalability in spatial resolution ensures us the application of transmitting or browsing images of different sizes.
1.1 Outline……………………………………………………………………2
2. SPIHT algorithm …………………………………………………………4
2.1 Wavelet transform and filter banks ………………………………4
2.2 SPIHT coding algorithm ………………………………………………8
2.2.1 Set partitioning……………………………………………………10
2.2.2 Spatial orientation trees ………………………………………10
2.2.3 Coding algorithm……………………………………………………12
2.3 Arithmetic coding ……………………………………………………14
2.3.1 Application of arithmetic coding on SPIHT algorithm ……16
2.4 Experimental results…………………………………………………17
2.4.1 Tests on wavelet……………………………………………………17
2.4.2 Tests on SPIHT………………………………………………………20
2.4.3 Tests on arithmetic coding………………………………………23
3.Wavelet coding incorporating perceptual models…………………27
3.1 Previously developed perceptual models…………………………30
3.1.1 JPEG luminance quantization table ……………………………30
3.1.2 Perceptual weights suggested by L Hontsch, L. J. Karam, and R. J. Safranek…………………………………………………………32
3.2 Perceptual weights calculated from the MTF function ………33
3.3 Experimental results and discussion ……………………………36
3.3.1 Experimental results………………………………………………36
3.3.2 Discussion……………………………………………………………39
4. Scalability in SNR and spatial resolutions ……………………50
4.1 SPIHT based coder with dual scalabilities ……………………51
4.2 Coding example…………………………………………………………54
5. Conclusion ………………………………………………………………57
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