Gain map generation, embedding, and application for high dynamic range digital image functionality
Gain map generation, embedding, and application for high dynamic range digital image functionality are described. In one example, a gain map is generated based on a digital image, e.g., as a ratio of a standard dynamic range digital image and a high dynamic range digital image. The gain map is configured to adjust an amount of gain of a digital image between a high dynamic range (HDR) and a standard dynamic range (SDR). Metadata is generated based on the gain map. The metadata describes how the gain map is to be applied to the digital image as part of rendering. The gain map, the metadata, and the digital image are embedded within a digital image file and stored.
1 . A method implemented by a processor, the method comprising:
generating, by the processor, a gain map based on a digital image, the gain map configured to adjust an amount of gain of the digital image between a high dynamic range (HDR) and a standard dynamic range (SDR), the gain map including pixel-by-pixel adjustment values supporting scalable continuous interpolation per color channel between the HDR and the SDR;
generating, by the processor, metadata based on the gain map, the metadata describing how the gain map is to be applied to the digital image as part of rendering by controlling a mapping between the HDR and the SDR based on gamma values per color channel, a minimum range capacity value, and a maximum range capacity value in support of the scalable continuous interpolation between the HDR and SDR;
embedding, by the processor, the gain map, the metadata, and the digital image within a digital image file; and
storing, by the processor, the digital image file in a storage device.
2 . The method as described in claim 1 , wherein the generating the gain map is based on a first version of the digital image configured according to the standard dynamic range (SDR) and a second version of the digital image configured according to the high dynamic range (HDR).
3 . The method as described in claim 2 , wherein the gain map is a ratio of luminosity or color values of the first and second versions of the digital image.
4 . The method as described in claim 1 , further comprising:
displaying a preview of the digital image in a user interface as rendered based on the gain map and the metadata;
receiving an edit to the gain map based on an input received via the user interface; and
wherein the embedding is performed using gain map having the edit.
5 . The method as described in claim 1 , wherein the gain map includes a plurality of said gain maps configured for respective color channels of the digital image.
6 . The method as described in claim 1 , wherein the metadata describes:
minimum, average, and maximum pixel luminance values;
the gamma values per color channel; or
the minimum and maximum capability value for interpolating the gain map.
7 . The method as described in claim 1 , further comprising displaying the digital image by a display device based on rendering the digital image using the gain map and the metadata from the digital image file.
8 . The method as described in claim 7 , wherein the rendering is based at least in part on an input specifying a high dynamic range (HDR) capability of the display device.
9 . The method as described in claim 8 , wherein the input specifies an amount that the gain map is to be scaled as part of the rendering.
10 . The method as described in claim 1 , wherein the digital image is configured as having the standard dynamic range (SDR) and the gain map and metadata are configured for use in rendering the digital image for display as having the high dynamic range (HDR).
11 . The method as described in claim 1 , wherein the digital image is configured as having the high dynamic range (HDR) and the gain map and metadata are configured for use in rendering the digital image for display as having the standard dynamic range (SDR).
12 . A computing device comprising:
a processor;
a sensor;
a display device; and
a computer-readable storage medium storing instructions that, responsive to execution by the processor, causes the processor to perform operations including:
receiving an input defining high dynamic range (HDR) capabilities available at the display device;
detecting, using the sensor, an environmental capability of an environment, in which, the display device is disposed;
scaling a gain map embedded as part of a digital image based on the high dynamic range (HDR) capabilities available at the display device defined by the input and the detected environmental capability, the scaling based on metadata having a minimum range capacity value, a maximum range capacity value, and gamma values per color channel describing how the gain map is to be applied to the digital image in support of scalable continuous interpolation between the HDR and a standard dynamic range (SDR) by controlling a mapping between high dynamic range and standard dynamic range, the gain map including pixel-by-pixel adjustment values supporting the scalable continuous interpolation per color channel between the HDR and the SDR; and
rendering the digital image for display by the display device by applying the scaled gain map to the digital image.
13 . The computing device as described in claim 12 , wherein the high dynamic range (HDR) capabilities are based on hardware device capabilities of the display device.
14 . The computing device as described in claim 12 , wherein the environmental capability is an amount of brightness of the environment, in which, the display device is disposed.
15 . The computing device as described in claim 12 , further comprising the display device configured to display the digital image having the applied gain map.
16 . The computing device as described in claim 12 , wherein the digital image is configured as having a standard dynamic range (SDR) and the gain map is configured to scale the digital image using the gain map based on the high dynamic range (HDR) capabilities available at the display device.
17 . The computing device as described in claim 12 , wherein the digital image is configured as having the high dynamic range (HDR) and the gain map is configured to scale the digital image using the gain map based on the high dynamic range (HDR) capabilities available at the display device.
18 . A method comprising:
receiving an input defining high dynamic range (HDR) capabilities available at a display device;
detecting, using a sensor, an environmental capability of an environment, in which, the display device is disposed;
scaling a gain map embedded as part of a digital image based on the high dynamic range (HDR) capabilities available at the display device defined by the input and the detected environmental capability, the scaling based on metadata having a minimum range capacity value, a maximum range capacity value, and gamma values per color channel describing how the gain map is to be applied to the digital image in support of scalable continuous interpolation between the HDR and a standard dynamic range (SDR) by controlling a mapping between range the HDR and the SDR that supports the scalable continuous interpolation per color channel between the HDR and the SDR, the gain map including pixel-by-pixel adjustment values supporting the scalable continuous interpolation per color channel between the HDR and the SDR; and
rendering the digital image for display by the display device by applying the scaled gain map to the digital image.
19 . The method as described in claim 18 , wherein the high dynamic range (HDR) capabilities are based on hardware device capabilities of the display device.
20 . The method as described in claim 18 , wherein the environmental capability is an amount of brightness of the environment, in which, the display device is disposed.