Fast and efficient side information generation in distributed video coding by using dense motion representations

Distributed video coding (DVC) does not demand motion estimation (ME) and compensation (MC) at the encoder, but only at the decoder and so it is more suitable for applications that require a simple encoder, like wireless sensor networks. In DVC the video sequence is split into Key Frames (KFs) and Wyner-Ziv Frames (WZFs): the first are intra-coded and the latter are coded by a channel code and only the parity bits are sent to the decoder. The KFs are available at the decoder, while we need to estimate the WZF and correct this estimation with parity bits. One critical step is the estimation of the WZF. The method of the state of the art, with which we compare, is given by DISCOVER. It estimates the WZF by linear interpolating the two adjacent KFs. We propose a higher order motion interpolation for WZF estimation by using four KFs. Due to the high computational efforts, we propose also a fast algorithm that halves the complexity of the previous method. We note that the results of the fast method are comparable with the original one. An other proposal is to increase the density of the motion vector field in order to improve the estimation of the WZF.