Vector assisted spatial interpolation

The technique of vector assisted spatial interpolation has been developed to reduce the effects of alias frequencies when images are spatially interpolated. A simple example is the conversion of video fields to frames, in the generation of stills or slow motion from an interlaced source. If only intra-field processing is considered the usual approach is to use a vertical interpolator. This can introduce artefacts such as loss of vertical resolution and flicker as well as accentuating the vertical alias in the image. Complex vertical interpolators can be designed to reduce the resolution loss and the flicker but they can do nothing to reduce the alias problem. The authors describe an alternative approach using spatial vectors to guide the direction of the interpolation filter on a pixel basis. The filter is applied along the direction of lowest frequency and has the desired result of `de-aliasing´ the image