Structure preserving error concealment with directional smoothness measure

We propose a directional smoothness measure for block-based error concealment through spatial correlation. Image structures revealed by consistent edge profiles are very important for subjective visual quality. We treat the problem of block reconstruction as consistent recovery of local image structures. The directional smoothness measure evaluates structural consistency along an edge elongation and is used as the object function for block reconstruction. Corrupted DCT coefficients are recovered by smoothly extending various edge profiles from surrounding areas to missing blocks. The reconstruction is adaptive to local image structures. Consistent cross-edge sharpness and along-edge smoothness are maximally preserved during the reconstruction. The proposed concealment method demonstrates encouraging improvement both in the subjective image quality and in the reconstruction PSNR over conventional schemes. It is applicable to various spatial and spectral interleaving systems and a fast implementation is also proposed