Digital video standards conversion in the presence of accelerated motion

Abstract

We address the standards conversion of digital video containing accelerated motion. The spectral characterization of video containing accelerated motion is performed by means of short time spectral analysis, where the support of the short time spectrum (STS) of video with accelerated motion is derived. Linear time-varying filters that operate along an accelerated motion trajectory are then analyzed, and the time-varying frequency response of these filters is computed. Finally, we show that the support of this time-varying frequency response matches that of the video signal STS, and thus filtering along the accelerated motion trajectory potentially yields the smallest amount of aliasing in standards conversion of video with accelerated motion. Experimental results comparing the performance of motion-compensated filtering along the accelerated motion trajectory with filtering along the constant velocity motion trajectory that is tangent to the accelerated trajectory at the processed frame are provided.