Upsampling filter for a down conversion system

摘要

An HDTV down conversion system including apparatus for forming a set of low resolution down-sampled pixel values corresponding to a current frame of a video signal from a set of low resolution pixel values corresponding to a residual image of a current frame of the video signal and from a set of down-sampled low resolution pixel values corresponding to reference frames of the video signal. The apparatus includes a memory for storing the set of down-sampled low resolution pixel values. An up-sampling processor receives from the memory and uses Lagrangian interpolation to convert the set of down-sampled low resolution pixel values corresponding to the reference frame of the video signal into a set of up-sampled low resolution pixel values corresponding to the reference frame of the video signal. A summing processor adds the set of low resolution pixel values corresponding to the residual image of the current frame of the video signal to the set of up-sampled low resolution pixel values corresponding to the reference frame of the video signal to form a set of low resolution pixel values corresponding to the current frame of the video signal. A decimating processor deletes selected ones of the set of low resolution pixel values corresponding to the current frame to generate the set of low resolution down-sampled pixel values corresponding to the current frame of the video signal.