Fast Algorithm for Fractal Image Compression with Quadtrees

• Main Authors: Wu Ming-Der, 吳明德
• Other Authors: 鄭志宏
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/87265501702131896756

碩士 === 義守大學 === 電機工程學系 === 87 === Fractal image compression algorithm has high compression ratio and high quality‚ but it needs very large amount of full-searchings and comparisons in the compressing process which is time consuming. Although quadtree decomposition fractal image compression algorithm has improved the quality of baseline fractal image compression algorithm, it takes much more time than baseline fractal image compression algorithm does. The compression speed of quadtree recomposition fractal image compression algorithm is faster than that of quadtree decomposition fractal image compression algorithm,but it is less effect. This thesis will discuss the baseline fractal image compression with DCT algorithm, the quadtree decomposition fractal image compression with DCT algorithm and the quadtree recomposition fractal image compression with DCT algorithm to reduce the encoding time. This thesis will discuss the reason why the baseline/quadtree fractal image compression with DCT algorithm takes less time than the traditional baseline/quadtree fractal image compression. The reason is the baseline/ quadtree fractal image compression with DCT algorithm calculates the eight orientations simultaneously. Finally, the complexity analysis is provided to prove the operations of the baseline/quadtree fractal image compression with DCT algorithm, in which the arithmetic operations are much than the traditional baseline/quadtree fractal image compression. This is why the encoding speed of the baseline/quadtree fractal image compression with DCT algorithm is faster than the traditional baseline/quadtree fractal image compression.