“A new quantization scheme for HDR two-layer encoding schemes” by Khan

  • ©Ishtiaq Rasool Khan



Entry Number: 04


    A new quantization scheme for HDR two-layer encoding schemes



    Two-layer encoding schemes for High dynamic range (HDR) images (and video) not only provide backward compatibility with the existing displays, but also preserve additional details in the second layer which can be important for certain applications. The first layer is for visualization and should be encoded at the best quality, however the residual data can be processed before encoding in the second layer, to maximize the amount of details that can be preserved. Most of the existing schemes use JPEG encoding for the second layer as well. However, JPEG is a lossy scheme designed to give more importance to visually important features. Therefore, it is not the best choice for encoding of the second layer, which does not necessarily have the same spectrum as that of the original image. Instead, a lossless scheme such as PNG would be a better choice. This would reduce the encoding problem to a better packaging of floating point data to integers of fixed bit depth. In other words, we need to devise a non-linear quantization scheme to minimize the loss, since the encoding after quantization would be lossless.


    1. Ward, G., and Simmons, M. 2005. JPEG-HDR: A Backwards-Compatible, High Dynamic Range Extension to JPEG. Thirteenth Color Imaging Conference.
    2. Mantiuk, R., Efremov, A., and Myszkowski, K. 2006. Backward Compatible High Dynamic Range MPEG Video Compression. SIGGRAPH. 
    3. Khan, I. R., 2008. Two layer scheme for encoding of high dynamic range images, ICASSP.


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