Abstract: An interpolation filter for video signals includes four circuits to improve video quality in both intra-field and inter-field modes. The interpolation filter is configured to interpolate according to the direction of an image edge. The interpolation filter is also configured to interpolate in a prescribed spatial direction when no image edges can be univocally determined. The first circuit detects an image edge of discrete image elements to generate a first signal. The second circuit uses output from the first circuit to generate a first signal corresponding to an average of the discrete image elements along a direction of the image edge. The third circuit uses output from the first circuit to detect a texture image area wherein an image edge cannot be univocally determined and for generating a second signal depending on a degree of existence of the image edge. The fourth circuit is supplied by the first signal, the second signal and a third signal.