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題 名 | 利用四方樹分割之碎形彩色影像壓縮的研究=A Study of Fractal Color Image Compression with Quadtrees |
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作 者 | 吳博雅; 李俊宜; | 書刊名 | 臺南師院學報 |
卷 期 | 30 1997.06[民86.06] |
頁 次 | 頁245-261 |
分類號 | 312.1 |
關鍵詞 | 四方樹分割; 碎形彩色影像壓縮; |
語 文 | 中文(Chinese) |
中文摘要 | 本篇文章主要探討利用四方樹分割之碎形彩色影像壓縮的原理及製作。為了實用 性,我們先剖析一般掃描器常用的 TIFF 影像檔案格式。其次,再研究利用四方樹分割之碎 形之彩色影像壓縮的原理。最後,由所探討的原理發展出其編碼及解碼演算法。 整個系統是先由掃描器將圖像輸入成 TIFF 檔。此檔含 tag 與影像內容兩部份。 我們保留 tag 部份,將 RGB 彩色影像內容轉換為 YIQ。 再利用四方樹分割的碎形壓縮來求最相似的 區域。四方樹分割的碎形壓縮是將圖像分割為值域以及邊長各為兩倍的對應之定義域,以動 態的方式先一整張影像為值域,對一值域如找不到在可容忍的情況下最相似的定義域,就將 值域分割為四塊較小的值域。編碼後的檔案只儲存最相似定義域之左上角座標,相似變換及 其亮度、原色、鮮明度之對比與明亮差。解碼時,隨意選取一影像,對編碼後的分割的逐次 函數系統作用在此影像上,直到影像收斂至視覺感覺不出差異的程度。 再將所得的檔案由 YIQ 變換成 RGB。然後再變換成 TIFF 檔。 |
英文摘要 | This paper is a study on the theory and the application of the fractal color image compreesion with quadtrees. For reality, we analyze the format of the TIFF image file. Then, to research the theory of the fractal color image compression with quadtrees. Finally, to develop the encoding algorithm and the decoding algorithm. The input of this system is TIFF files generated by scanners. These files contain the tag part and the image RGB content part. We preserve the tag part and transform the RGB content into the YIQ content, and then to find the most similar domain by the fractal compression with quadtrees. The fractal image compression with quadtrees partitions the image into nonverlapping ranges and overlapping domains with double sizes. Initialized by the image as a range. For each range, we find out the most similar domain under a tolerable level. If not found, the range will be partitioned into four smaller ones and go on working. The encoded file is saved by the left-upper coordinate of the most similar domain, affine transformation; and the contrast and the brightness of the luminance, the hue and the saturation. While decoding, we transform an arbitrary image iteratively until the image is convergent to the original image. Then, transform the file from the YIQ content back to the RGB content. At last, the image file is back to a TIFF file. |
本系統中英文摘要資訊取自各篇刊載內容。