Optimizing a Tone Curve for Backward-Compatible High Dynamic Range Image and Video Compression

  • Authors:

  • Zicong Mai;H. Mansour;R. Mantiuk;P. Nasiopoulos;R. Ward;W. Heidrich

  • Affiliations:

  • Dept. of Electr. & Comput. Eng., Univ. of British Columbia, Vancouver, BC, Canada;-;-;-;-;-

  • Venue:
  • IEEE Transactions on Image Processing
  • Year:
  • 2011

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Abstract

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.