Lossless Image Compression Method Based on Block Grouping

• Main Authors: Hsin-Nan Tsai, 蔡信男
• Other Authors: Herng-Yow Chen
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/07527856618461595422

碩士 === 國立暨南國際大學 === 資訊工程學系 === 95 === This thesis proposes a lossless image compression technique for gray level images. This method employs a median edge detector (MED) on the input image to produce a difference image and a sign image. Then, in order to reduce the complexity of the sign image, bits transformation is adopted to transform the bits between the sign image and the most significant bits (MSB) in difference image. The resultant image blocks, according to the maximum value of image block, are classified into data bins, each of which has different data patterns. Finally, the arithmetic coding method is applied to compress the data in each data bin respectively. The result of this thesis shows that the proposed method when applied in smooth images provides a better bit rate than JPEG 2000 lossless method does. And the result is also better than other lossless compression methods such as GIF, PNG, and TIFF.