| Summary: | 碩士 === 國立交通大學 === 電子工程系所 === 92 === JPEG2000 is the successor to the JPEG image compression standard, which offers superior compression performance and special features demanded by modern applications. It employs fundamentally different approaches and many recently developed techniques to achieve these goals. In this thesis, we have focused on the study of the cores in JPEG2000 – the discrete wavelet transform (DWT) and the embedded quantizer. In the first part, we compare the direct computation, Winograd algorithm, and lifting algorithm for DWT, and analyze the computational complexity under various application specifications of different image sizes and the so-called motion JPEG2000 conditions. Moreover, we propose a low-cost implementation based on the distributed arithmetic (DA). The implementation result shows that the DA-based lifting architecture requires only 45% silicon area of the MAC-based design for compression specification of common 30 640×480 frames per second. In the second part, we investigate the performance of existing quantization schemes for DWT coefficients. We then propose a content-aware quantization scheme, which allocates bits according to the power magnitudes of the DWT subbands. The simulation results show that it provides better PSNR than the conventional quantization schemes under the same bit rate condition.
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