Super resolution of video using key frames
In many video compression systems, the frames are down-sampled before transmission. Also, in many scalable systems, the residual after down- and up-sampling is encoded and transmitted. Sometimes, a few frames are encoded at normal resolution (key frames) while the other frames are encoded at reduced resolution. Super resolution can be used to enhance the up-sampling process, using motion information to improve traditional interpolation. In this paper, we propose to use a super resolution method to up-sample the non-key frames using the key frames as reference. We build dictionaries on-the- fly using the key frames instead of the traditional off-line training images. The high-frequency data of matching blocks are added to the low-resolution blocks. Since the key frames are very similar to the non-key frames, the method is robust enough to allow successful super resolution of highly compressed (severely degraded) sequences. Results are presented for many predefined block sizes, key frames frequencies, and compression parameters.