In a method and device for determining the spacing between first and second sequences of signal values, first and second successive signal values of the first sequence have assigned thereto a third signal value of the second sequence, the third signal value being located temporally or spatially between the first and second signal values of the first sequence. A first spacing value is determined based on a mixing value from the first and second signal values, a second spacing value between the mixing value and the third signal value, an interval width value based on the width of an interval defined by the first and second signal values, and mapping of the second spacing value onto the first spacing value using the interval width value such that a mapping curve has at least two segments with different slopes, where the slope of the curve, at least in segments, is shallower for second spacing values smaller than the interval width value than for second spacing values larger than the interval width value, and such that for at least one second spacing value smaller than the interval width value, the resulting first spacing value is smaller than this second value. A plurality of first spacing values are determined, and then added to determine the spacing between the two signal sequences.

An apparatus and method for improving the VT filter performance for moving pictures by deinterlacing. A VT filter unit receives data of a deinterlacing target field (field #n) and data of forward and backward fields of the target field (fields #n-1 and #n+1). A difference operation unit receives data of two frames including the field #n, and calculates the sum of the absolute values of differences between these frames. A filter coefficient setting unit decides a filter coefficient based on the sum of the absolute values of the differences. The VT filter unit subjects the inputted pixels to the filtering by using the filter coefficient to generate an interpolation pixel, and outputs the generated interpolation pixel. A double-speed converter composes the interlaced image and the interpolation pixel to convert the frame rate to be doubled, and outputs the converted image as a progressive image.

A motion decision value provides a dependable estimate whether motion occurs in a given region of a video image in an interlaced video sequence. The motion detection is particularly applicable in the conversion from interlaced video to progressive video. An input first is fed to an absolute value former which computes a frame difference signal from a difference between the first field and the second field in one frame. A point-wise motion detection in the frame difference signal is then followed by a region-wise motion detection that combines the point-wise motion detection signal with an adjacent point-wise motion detection signal delayed by one field. The motion decision value is then computed from the region-wise motion detection signal and output for further processing in the video signal processing system, such as for choosing whether the spatially interpolated video signal value or the temporally interpolated video signal value should be used for the output.