Encoding, decoding, and representing high dynamic range images
First Claim
1. A processor non-transitory readable medium having stored thereon an image file structure for representing a high dynamic range image in a compressed format, the image file structure comprising:
- a compressed tone-mapped image in a standard-based compression format; and
high dynamic range (HDR) reconstruction data, wherein the HDR reconstruction data comprise;
a quantized luma ratio image comprising log ratio pixel values;
luma de-quantization parameters for the quantized log ratio pixel values;
one or more sets of quantized residual chroma values; and
chroma de-quantization parameters for the one or more sets of quantized residual chroma values, wherein the compressed tone-mapped image is separated by the HDR reconstruction data using one or more application markers.
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Abstract
Techniques are provided to encode and decode image data comprising a tone mapped (TM) image with HDR reconstruction data in the form of luminance ratios and color residual values. In an example embodiment, luminance ratio values and residual values in color channels of a color space are generated on an individual pixel basis based on a high dynamic range (HDR) image and a derivative tone-mapped (TM) image that comprises one or more color alterations that would not be recoverable from the TM image with a luminance ratio image. The TM image with HDR reconstruction data derived from the luminance ratio values and the color-channel residual values may be outputted in an image file to a downstream device, for example, for decoding, rendering, and/or storing. The image file may be decoded to generate a restored HDR image free of the color alterations.
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Citations
13 Claims
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1. A processor non-transitory readable medium having stored thereon an image file structure for representing a high dynamic range image in a compressed format, the image file structure comprising:
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a compressed tone-mapped image in a standard-based compression format; and high dynamic range (HDR) reconstruction data, wherein the HDR reconstruction data comprise; a quantized luma ratio image comprising log ratio pixel values; luma de-quantization parameters for the quantized log ratio pixel values; one or more sets of quantized residual chroma values; and chroma de-quantization parameters for the one or more sets of quantized residual chroma values, wherein the compressed tone-mapped image is separated by the HDR reconstruction data using one or more application markers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification