ENCODING, DECODING, AND REPRESENTING HIGH DYNAMIC RANGE IMAGES

摘要

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.

主权项

1. An apparatus comprising a bitstream stored on a non-transitory machine-readable media, wherein the bitstream is characterized by high dynamic range image data in a compressed format, wherein the compressed format comprises:
a compressed JPEG base image; high dynamic range (HDR) reconstruction data, wherein the HDR reconstruction data comprise a quantized luma ratio image and one or more sets of quantized residual chroma values; and a JPEG application marker separating the base image from the HDR reconstruction data.