Research On Block Truncation Coding Method Used For Image Information Hiding

Block truncation coding is a simple and fast image coding method with high timing capability, and not sensitive to disturb in the channel. It was applied in image processing area since it appeared, especially in the areas of martial communication and artificial satellite communication.Recently, the block coding method was applied in the area of information hiding. The information was hidden in the image based on the characteristic of the coding method, and the method did not change the pixel of the image and did not increase the redundant information. The receiver can extract the information without distortion.The block truncation coding method is improved and applied in image information hiding. The method divides the cover image into overlapped blocks, and judges the type of the quantization according to the detail of each block. These blocks are divided into three conditions according to the degree of the value change in each block, and the blocks are encoded with mean value quantization, two levels quantization and four levels quantization on the basis of the three conditions. Then sender arrays the order of the quantization levels according to the hidden information, one bit information is hidden in the block of two levels, four bits information are hidden in the block of four levels, and nothing is hidden in the block of mean value block. The receiver extracts the information in line with the order of quantization levels and recovers the carrier image. The method improves the original block truncation coding method and the quality of the recovered image. The information hiding method is improved.In this paper the principle of block truncation coding, lossless hiding method and lossless extracting method are introduced specifically,and the hiding capacity and image quality after hiding of this method are also analyzed. At last, experimental results with MATLAB? are provided to demonstrate the effectiveness of the proposed method.