Encoding, Decoding, and Representing High Dynamic Range Images
First Claim
1. A method, comprising:
- receiving a high dynamic range (HDR) image;
generating a tone-mapped (TM) image based on the HDR image;
generating a luminance ratio image, the luminance ratio image comprising luminance ratio values generated by dividing luminance values of the HDR image with luminance values of the TM image;
applying the luminance ratio values to the HDR image to create a re-mapped image;
determining residual chroma values based on the re-mapped image and the TM image;
generating a log ratio image based on the luminance ratio image; and
generating a coded HDR image, the coded HDR image comprising the TM image and HDR reconstruction data, the HDR reconstruction data being derived from the log ratio image and the residual color values.
1 Assignment
0 Petitions
Accused Products
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.
-
Citations
16 Claims
-
1. A method, comprising:
-
receiving a high dynamic range (HDR) image; generating a tone-mapped (TM) image based on the HDR image; generating a luminance ratio image, the luminance ratio image comprising luminance ratio values generated by dividing luminance values of the HDR image with luminance values of the TM image; applying the luminance ratio values to the HDR image to create a re-mapped image; determining residual chroma values based on the re-mapped image and the TM image; generating a log ratio image based on the luminance ratio image; and generating a coded HDR image, the coded HDR image comprising the TM image and HDR reconstruction data, the HDR reconstruction data being derived from the log ratio image and the residual color values. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A method, comprising:
-
parsing an image file comprising a tone-mapped (TM) base image and high dynamic range (HDR) reconstruction data, the HDR reconstruction data comprising quantized log ratio luminance values and quantized residual chroma values; computing quantization parameters relating to the quantized log ratio luminance values and the quantized residual chroma values; converting, based at least in part on the quantization parameters, the quantized log ratio luminance values and the quantized residual chroma values into ratio luminance values and residual chroma values; and reconstructing an HDR image using the TM base image the ratio luminance values and the residual chroma values. - View Dependent Claims (13, 14, 15, 16)
-
Specification