Title :
Computationally efficient tone-mapping of high-bit-depth video in the YCbCr domain
Author :
Mai, Zicong ; Nasiopoulos, Panos ; Ward, Rabab K.
Author_Institution :
Electr. & Comput. Eng. Dept., Univ. of British Columbia, Vancouver, BC, Canada
Abstract :
High dynamic range (HDR) video content is able to provide superior picture quality. This is because the representation of HDR signals requires more bits than the 8-bit low dynamic range (LDR) video. Tone-mapping is the process that converts HDR to LDR signals. Most tone-mapping methods are derived only for the luminance component. This mapping function is then used in each of the R, G and B components to generate the LDR color image. This color tone mapping correction approach, however, cannot be directly applied to most videos since they are usually encoded in the YCbCr color space. This paper addresses this problem and proposes a tone-mapping method that is applied directly on the YCbCr signals. Experimental results show that the Cb and the Cr signals generated by our method are almost identical to those produced with the conventional pipeline up to round-off errors, with average PSNR at about 55 dB and average SSIM at 0.991. By avoiding all the round-off errors introduced in the conventional method, our approach provides a more accurate LDR picture. Moreover, the proposed solution has significantly lower complexity because it bypasses the processes such as color space transformation and up-sampling which are required by the conventional method.
Keywords :
brightness; image colour analysis; video coding; video signal processing; HDR; color image; color space transformation; color tone mapping correction; computationally efficient tone-mapping; high dynamic range video; high-bit-depth video; low dynamic range video; luminance component; mapping function; round-off errors; word length 8 bit; Color; Dynamic range; Equations; Image color analysis; PSNR; Pipelines; Standards; Scalable video coding; high dynamic range (HDR); tone-mapping;
Conference_Titel :
Acoustics, Speech and Signal Processing (ICASSP), 2012 IEEE International Conference on
Conference_Location :
Kyoto
Print_ISBN :
978-1-4673-0045-2
Electronic_ISBN :
1520-6149
DOI :
10.1109/ICASSP.2012.6288176