Packet loss concealment in baseline JPEG coded images

Loss of coded data can affect a JPEG decoded image to a large extent, making concealment of errors caused by data loss an important issue. Reconstruction of JPEG coded images in an error-prone channel environment is investigated in this paper. First a method for estimating the missing DC coefficients of a JPEG coded image which is required for decoding the compressed image, is suggested and evaluated. As the effects of errors in estimating the missing DC value will appear as stripes across the image, a post-processing technique for removing such stripes is then developed. Finally the missing data is reconstructed by exploiting the correlation between adjacent blocks. A novel reconstruction technique which has a good performance in reconstruction of edges is proposed. A key contribution of our work is that, unlike in previously published reconstruction algorithms, differential encoding of the DC coefficients is assumed. Simulation results indicate that the performance of our algorithm is very good, even when many packets are lost during transmission of the JPEG coded image.