Based on a thorough analysis of the JPEG standard (CCITT T.81) and error correction theory, convolutional codes combined with BCH codes are used in progressive mode of JPEG. With this FEC technique, the header and specification tables of JPEG file are protected by the convolutional codes while others by the BCH codes. A method for image concealment is also presented according to the special file structure of JPEG standard, which enables the concealment of corrupted high frequency information byæŠorrect low frequency one in the same image. With which the image damages caused by the channel error can be successfully concealed. Proposed method has been applied to actual military image communications system.
|