一种改进的基于汉明纠错码的图像恢复算法

为减少汉明纠错译码时出现的错误,以减少错纠和乱纠的可能和提高恢复图像的质量,提出了一种改进的基于汉明纠错码的图像恢复算法。该算法首先将灰度图像的最高位平面(MSB)分成4大块;然后再将每大块分成4小块,并进行小块的垂直对调,同时对处理后的4大块中相同像素位置处的二进制位进行(7,4)汉明编码;最后将产生的3个监督位平面各自进行大块内小块的对角对调,再将处理后的3个大块按监督位顺序依次嵌入到原始图像的前面3大块的对应像素的最低位(LSB)。第2重要位平面(2MSB)和第3重要位平面(3MSB)也进行同样处理,并分别嵌入到次低位(2LSB)和再次低位(3LSB)。实验结果表明,该改进方法比原方法在剪切、替换、均值和中值滤波以及JPEG有损压缩情况下,可取得更好的图像恢复效果,且恢复算法带来的噪声大大减少。

An Improved Algorithm of Restoring Image Based on Hamming Error-correcting Codes

For reducing the errors which arisen during Hamming error-correcting decoding so that the likelihood of mistakenly and randomly rectifying is cut down and the quality of restored image is improved,an improved algorithm of restoring image based on Hamming error-correcting codes is presented. This algorithm first divides the most significant bit (MSB)plane of a grayscale image into four big blocks.Then each big block is divided into four small blocks and they are exchanged vertically in a big block.Secondly,the four binary bits at the same pixel position of four big blocks are encoded according to (7,4) Hamming encoding and the three checkout bit plane big blocks are implemented with diagonal exchanging in itself,then the exchanged three big blocks are embedded into the least significant bit(LSB) of corresponded pixel of the first three big blocks of the original image orderly according to checkout bit sequence.Then the second most significant bit plane(2MSB) and the third one(3MSB) are operated using above algorithm and embedded respectively into the second least significant bit plane(2LSB) and the third one(3LSB). The experiment results indicate that the improved method has obtained better restored image effect than the original one in the circumstance of cutting,replacing,average filtering and median filtering,and JPEG lossy compression.And the noise caused by the restored algorithm is reduced largely.