- 作者: 謝朝和;呂伯強
- 作者服務機構: 中正理工學院電機系
- 中文摘要: 塊截取編碼係利用二階度影像塊以代表數位化影像之一簡易且有效之影像資料壓縮方法。 本文提出塊截取褊碼之修正方法。此方法採用影像塊分類技術,將影像塊經臨限運作而加以分類。至於臨限參數則使用影像塊的標準差及相鄰影像塊標準差的差額。此一修正方法經證實可以獲得頗高的壓縮比。雖然經壓縮後的資料率隨著畫面之不同而有所差異,然而就一般畫面而言,此方法可以將塊截取編碼1.63位元/像素之資料率降低到約0.7位元/像素,而尚不致於導致明顯的畫面失真以及增加硬體化的複雜度。
- 英文摘要: Block Truncation Coding (BTC) is a simple and efficient image data compression algorithm whichuses two-level blocks to represent digitized images. This paper describes a modified algorithm of basic BTC which adopts a block classification techniquein which a threshold operation is performed on the image blocks. The operation uses the standard devia-tion of a block and its difference between horizontal adjacent blocks as threshold parameters. The modifi-cation algorithm is found to be useful to obtain a high data compression ratio. Although the resulting datarate varies from picture to picture, the modified algorithm can reduce the standard BTC rate of 1.63bits/pel to about 0.7 bits/pel for ordinary pictures without introducing noticeable degradation of thepicture quality or complicating the hardware implementation.
- 中文關鍵字: BTC (block truncation coding); median filter; data rate; bit plane
- 英文關鍵字: --