Changing the temporal sample rate of a motion-image sequence

摘要

A frame-rate conversion system having an interpolation mode and a synchronization mode. The synchronization mode is selected when temporal interpolation confidence is and images can be retimed without dropping or repeating of images. The interpolation mode is selected when the measure of temporal interpolation confidence is high or repeating of images. Images are exchanged between a temporal interpolator and a buffer at an exchange rate which is varied in the interpolation mode to optimise the buffer occupancy for retiming of images without dropping or repeating of images in s subsequent synchronization.

主权项

1. Apparatus for changing the temporal sample rate of a motion-image sequence in which an input image sequence at an input rate is converted to an output image sequence at an output rate, the apparatus comprising;
a temporal interpolator, which serves to provide a measure of temporal interpolation confidence which measure varies in dependence upon the content of the images being interpolated and which is low when objectionable interpolation artefacts are expected; a buffer associated with the temporal interpolator and having a buffer occupancy which varies between full and empty limits; and a controller supplied with said measure of temporal interpolation confidence and a measure of said buffer occupancy; wherein the apparatus has:
an interpolation mode in which the output image sequence is formed by temporal interpolation between images of the input sequence; anda synchronisation mode in which the output image sequence is formed by re-timing of images of the input sequence without temporal interpolation images, with said buffer occupancy varying accordingly, it being necessary to drop or repeat an image if the buffer occupancy reaches a limit; the controller being adapted to select the synchronisation mode when the measure of temporal interpolation confidence is low and the measure of buffer occupancy indicates that images can be retimed without dropping or repeating of images and to select the interpolation mode when the measure of temporal interpolation confidence is high or when the measure of buffer occupancy indicates that images cannot be retimed without dropping or repeating of images.