Error concealment using joint multiple description coding and zero padding

There has been an increasing usage of Multiple Description Coding (MDC) for error concealment in non ideal channels. This paper attempts to conceal the error and reconstruct the lost descriptions by combining MDC and DCT transform with zero padding. At first DCT is applied to image then zeros are added to rows and columns of the image in the DCT domain. The obtained image from this process has lots of correlation between their pixels. After this process the image is down sampled to 4 sub images and DCT transform is used to map image pixels to transform domain and then by using multiple description scalar quantization (MDSQ) each sub image is quantized and converted to 2 descriptions. So finally there are eight descriptions gained after MDSQ. These data are transmitted into channel. At the receiver side these descriptions are added together but if some of descriptions corrupted or damaged because of channel failure, by taking average of other received descriptions, corrupted descriptions are reconstructed (error concealing method). Then inverse DCT is applied to subimages. By upsampling 4 obtained subimages, reconstructed image is gained. Simulations results show that PSNR values and subjective evaluations are increased as compared to other methods. Since zero padding is used, correlations of image pixels are increased. So quantization variance is low.