ROI based near lossless hybrid image compression technique

Region of Interest based compression is an efficient method of compression for images with a particular part to be most significant. It is always a better choice to compress the ROI with lossless compression while the rest of image with lossy compression technique. This paper deals with the compression of color images with the face of the person (ID cards, voter ID). This paper proposes lossless compression for face (ROI) and near lossless compression for the rest of the image. Image other than ROI may contain information that is useful, that is why it is appropriate to use near lossless compression for the rest of the image. Face detection suggested in this paper detects the face with the detection of skin color and natural dimensional ratio of height to width of normal human face. In this method of compression, PSNR obtained is remarkable and compression ratio can be increased by increasing the base value which is in power of two. In this method of compression, face will be compressed completely lossless by using Huffman coding and Snake difference scanning is used for achieving a good compression ratio. Proposed algorithm provides quality PSNR with reasonable CR with lossless compression of ROI.