Title :
Using a region-based blurring method and bits reallocation to enhance quality on face region in very low bitrate video
Author :
Chen, Chang-Hong ; Chen, Liang-Gee ; Chang, Hao-Chieh
Author_Institution :
Dept. of Electr. Eng., Nat. Taiwan Univ., Taipei, Taiwan
fDate :
31 May-3 Jun 1998
Abstract :
A region-based blurring algorithm to reduce bitrate in very low bitrate video coding is proposed. This algorithm reduces the bitrate by passing the original background image through a filter before motion estimation. Each frame in original sequence will be segmented into foreground and background at first. The background part, which is of less importance for human vision, will be blurred through a blurring filter, while the foreground is kept unchanged. The bitrate for head-and-shoulder type sequences can achieve 5%~20% bitrate saving by this blurring algorithm. According to the human vision model, PSNR degradation in the background is not evident. Using this blurring algorithm, but keeping the coded bitstream at the same bitrate as the original sequence, about 0.5~1 dB gain in the foreground can be achieved due to bits reallocation between foreground and background
Keywords :
filtering theory; image enhancement; image segmentation; motion estimation; video coding; PSNR degradation; background image; bits reallocation; blurring filter; face region; foreground image; head/shoulder type sequences; human vision model; motion estimation; region-based blurring method; very low bit rate video; video coding; Bit rate; Degradation; Discrete cosine transforms; Filters; Humans; Image segmentation; Motion estimation; Quantization; Transform coding; Video coding;
Conference_Titel :
Circuits and Systems, 1998. ISCAS '98. Proceedings of the 1998 IEEE International Symposium on
Conference_Location :
Monterey, CA
Print_ISBN :
0-7803-4455-3
DOI :
10.1109/ISCAS.1998.698777