Motion compensated de-interlacing and motion estimation based on Yen's generalisation of the sampling theorem (GST) have been proposed by Delogne and Vandendorpe. Motion estimation methods using three-fields have been designed on a block-by-block basis, minimising the difference between two GST predictions. We will show that this criterion degenerates into a two-fields criterion, leading to erroneous motion vectors, when the vertical displacement per field period is an even number of pixels. We provide a solution for this problem, by adding a term to the matching criterion.
Yen's generalisation of the sampling theorem has been proposed as the theoretical solution for de-interlacing by Delogne and Vandendorpe. The solution results in a vertical interpolation filter with coefficients that depend on the motion vector value, which uses
samples that exist in the current field and additional samples from a neighbouring field shifted over (part of) a motion vector. We propose a further generalisation, where we design vector-adaptive inseparable 2D filters, which use samples from the current and the motion compensated previous field that are not available for all vectors on
a vertical line. The resulting inseparable filters give a better interpolation quality at a given number of input pixels. We will show that the algorithm can be made robust against the sensitivity to inaccurate motion vectors.