Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC, Canada.
IEEE Trans Image Process. 2011 Jun;20(6):1558-71. doi: 10.1109/TIP.2010.2095866. Epub 2010 Dec 3.
For backward compatible high dynamic range (HDR) video compression, the HDR sequence is reconstructed by inverse tone-mapping a compressed low dynamic range (LDR) version of the original HDR content. In this paper, we show that the appropriate choice of a tone-mapping operator (TMO) can significantly improve the reconstructed HDR quality. We develop a statistical model that approximates the distortion resulting from the combined processes of tone-mapping and compression. Using this model, we formulate a numerical optimization problem to find the tone-curve that minimizes the expected mean square error (MSE) in the reconstructed HDR sequence. We also develop a simplified model that reduces the computational complexity of the optimization problem to a closed-form solution. Performance evaluations show that the proposed methods provide superior performance in terms of HDR MSE and SSIM compared to existing tone-mapping schemes. It is also shown that the LDR image quality resulting from the proposed methods matches that produced by perceptually-based TMOs.
为了实现向后兼容的高动态范围（HDR）视频压缩，通过对原始 HDR 内容的压缩低动态范围（LDR）版本进行逆色调映射，重建 HDR 序列。在本文中，我们表明，适当选择色调映射算子（TMO）可以显著提高重建 HDR 的质量。我们开发了一种统计模型，该模型可以近似色调映射和压缩综合过程产生的失真。使用该模型，我们制定了一个数值优化问题，以找到最小化重建 HDR 序列中均方误差（MSE）的色调曲线。我们还开发了一种简化的模型，将优化问题的计算复杂度降低为闭式解。性能评估表明，与现有的色调映射方案相比，所提出的方法在 HDR MSE 和 SSIM 方面提供了更好的性能。还表明，所提出的方法产生的 LDR 图像质量与基于感知的 TMO 产生的质量相匹配。
