US 11,711,486 B2
Image capture method and systems to preserve apparent contrast of an image
Elizabeth G. Pieri, Campbell, CA (US); Robin Atkins, Vancouver (CA); and Jaclyn Anne Pytlarz, Santa Clara, CA (US)
Assigned to Dolby Laboratories Licensing Corporation, San Francisco, CA (US)
Appl. No. 17/253,600
Filed by Dolby Laboratories Licensing Corporation, San Francisco, CA (US)
PCT Filed Jun. 13, 2019, PCT No. PCT/US2019/037066
§ 371(c)(1), (2) Date Dec. 17, 2020,
PCT Pub. No. WO2019/245876, PCT Pub. Date Dec. 26, 2019.
Claims priority of provisional application 62/686,371, filed on Jun. 18, 2018.
Claims priority of application No. 18178266 (EP), filed on Jun. 18, 2018.
Prior Publication US 2021/0250564 A1, Aug. 12, 2021
Int. Cl. H04N 5/58 (2006.01); H04N 1/60 (2006.01); H04N 9/64 (2023.01); H04N 9/79 (2006.01); H04N 23/71 (2023.01); H04N 23/75 (2023.01); H04N 5/57 (2006.01); H04N 5/20 (2006.01); H04N 5/202 (2023.01)
CPC H04N 5/58 (2013.01) [H04N 1/6088 (2013.01); H04N 5/20 (2013.01); H04N 5/202 (2013.01); H04N 5/57 (2013.01); H04N 9/643 (2013.01); H04N 9/79 (2013.01); H04N 23/71 (2023.01); H04N 23/75 (2023.01)] 13 Claims
OG exemplary drawing
 
1. A method comprising:
receiving an image captured by a camera, the image including a first plurality of image data representing pixels in the image;
determining an estimated ambient light level of the image based on the first plurality of image data, wherein the estimated ambient light level is determined by scaling pixel values from a sensor in the camera using a function that includes a camera specific parameter and exposure parameters used on the camera when the image was captured to obtain one or more absolute scene light levels, the exposure parameters including an aperture setting, an exposure time setting and a sensor sensitivity setting and wherein the camera specific parameter is derived from a camera calibration;
computing an optical-optical transfer function, OOTF, based on the estimated ambient light level;
transforming image data derived from the first plurality of image data by correcting the image data derived from the first plurality of image data using the OOTF, the transforming configured to preserve an apparent contrast of the image under the estimated ambient light level in a viewing environment when the image is displayed on a target display in the viewing environment, wherein the OOTF includes corrects the image data based on a difference between the estimated ambient light and a predetermined or dynamically measured ambient light of the viewing environment and wherein the OOTF corrects the image data when the camera was set in automatic exposure mode but the image is displayed, without the OOTF correction, on the target display in the viewing environment when the camera was set with a manual exposure adjustment;
mapping, through a tone mapping function configured for the target display, image data derived from the first plurality of image data to map the image for display on the target display, the tone mapping function configured based on the gamut and luminance parameters of the target display, and wherein the mapping, through the tone mapping function, is performed after the transforming.