- 作者: 湯耀中
- 作者服務機構: 國立臺灣大學資訊工程系
- 中文摘要: 近年來,在數位影像處理與經由低容量傳輸媒介數據通信之結合應用中,漸進式傳輸技術廣泛地被採用。本論文在描述一彩色影像漸進式傳輸系統的設計及模擬。此系統乃是利用個人型電腦配備AT&T的影像捕捉板,使用C程式語言而製作完成。 系統中將原來的影像分割為若干子區段後,用快速離散餘弦變換方法加以變碼處理。所有子區段經過變碼處理後,依據每個子區段內影像的活動度,也就是所測得的交流能量,而加以排序並劃分為四個等級。變碼後信號傳輸時的排序則取決於每個等級中進入點內整體影像變化性的大小;變化性愈大則愈優先傳送。在變碼處理中,使用均一量子化方法,並分配每個傳輸階段的編碼位元數,以提供調適性編碼。本文並描述一有效方法用以完成影像漸進重整時,稀距陣的逆變換。最後並以一系列的模擬結果來評估此系統的效能。
- 英文摘要: Progressive Transmission Technologies have been recently applied in the field of digital image pro-cessing combined with data communication via low capacity transmission medium. This paper describesthe design and simulation of a progressive color image transmission system which is implemented on apersonal computer in which has been installed an AT&T Image Capture Board, using C language. The Fast Discrete Cosine Transform and adaptive uniform quantization are used in transform coding.FDCT sub-blocks are sorted into four classes according to image activity level. The progressive transmissionordering is dependent upon entry ensemble variance among all entries in each class, favoring the higherlevels of activity over lower levels. Some methods are used for efficient inverse transform of the sparsematrices during the procedure of intermediate reconstruction of image approximations. A series of simula-tions are conducted to evaluate the system performance and the results are presented.
- 中文關鍵字: progressive image coding; picture data compression
- 英文關鍵字: --