Spatio-temporal selective extrapolation for 3-D signals applied to concealment in video communications

In this paper we derive a frequency selective extrapolation method for three-dimensional signals. Extending a signal beyond a limited number of known samples is commonly referred to as signal extrapolation. We provide an extrapolation technique which enables to estimate image areas by exploiting simultaneously spatial and temporal correlations of the video signal. Lost areas caused by transmission errors are concealed by extrapolation from the surrounding. The missing areas in the video sequence are estimated conventionally from either the spatial or temporal surrounding. Our approach approximates the known signal by a weighted linear combination of 3-D basis functions from spatial as well as temporal direction and extrapolates it into the missing area. The algorithm is able to extrapolate smooth and structured areas and to inherently compensate motion and changes in luminance from frame to frame.