A color gamut mapping scheme for backward compatible UHD video distribution

The new Ultra High Definition (UHD) standard digital imagery can represent much more color information than High Definition (HD) and Standard Definition (SD). Currently most manufactured displays support UHD colors while UHD is being deployed for content production. However not all service providers have updated their pipeline thoroughly. Thus, the enduser that buys a UHD display would not be able to benefit from the wider UHD color range. In this paper, we propose an invertible gamut mapping from UHD colors to HD colors so that UHD displays can reconstruct UHD colors, while HD displays are addressed directly using legacy video delivery pipeline. The proposed color mapping scheme allows the mapped signal to be converted back to the original signal with minimal perceptual error so that the viewers' quality of experience (QoE) is preserved. Our method includes a parameter that adjusts the trade-off between the quality of the HD content and that of the UHD content. Our experiment results provide a guideline on how to strike a balance between color errors in the mapped signal and the retrieved one.