  In the past years, video communication has found its application in an
increasing number of environments. Unfortunately, some of them are error-prone
and the risk of block losses caused by transmission errors is ubiquitous. To
reduce the effects of these block losses, a new spatio-temporal error
concealment algorithm is presented. The algorithm uses spatial as well as
temporal information for extrapolating the signal into the lost areas. The
extrapolation is carried out in two steps, first a preliminary temporal
extrapolation is performed which then is used to generate a model of the
original signal, using the spatial neighborhood of the lost block. By applying
the spatial refinement a significantly higher concealment quality can be
achieved resulting in a gain of up to 5.2 dB in PSNR compared to the unrefined
underlying pure temporal extrapolation.
