US 12,462,360 B2
Display-optimized HDR video contrast adaptation
Rutger Nijland, Venlo (NL)
Assigned to Koninklijke Philips N.V., Eindhoven (NL)
Appl. No. 18/558,550
Filed by KONINKLIJKE PHILIPS N.V., Eindhoven (NL)
PCT Filed Apr. 24, 2022, PCT No. PCT/EP2022/060792
§ 371(c)(1), (2) Date Nov. 2, 2023,
PCT Pub. No. WO2022/233612, PCT Pub. Date Nov. 10, 2022.
Claims priority of application No. 21172660 (EP), filed on May 7, 2021.
Prior Publication US 2024/0221135 A1, Jul. 4, 2024
Int. Cl. H04N 21/422 (2011.01); G06T 5/50 (2006.01); G06T 5/92 (2024.01); H04N 21/485 (2011.01)
CPC G06T 5/92 (2024.01) [G06T 5/50 (2013.01); H04N 21/42202 (2013.01); H04N 21/4854 (2013.01); G06T 2207/10016 (2013.01); G06T 2207/20208 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A method of determining an output image comprising:
receiving an input image;
receiving a reference luminance mapping function as metadata, wherein the metadata is associated with the input image,
wherein the input image has input pixels,
wherein the input pixels have input luminances,
wherein the input luminances fall within an input luminance dynamic range,
wherein the input luminance dynamic range has an input maximum luminance,
wherein the reference luminance mapping function specifies a relationship between luminances of collocated pixels in the input image and a reference image,
wherein pixels in the reference image have reference luminances,
wherein at least a portion of the input luminances are different from the reference luminances,
wherein the reference image has a reference maximum luminance;
determining a locus of points so as to form an adapted luminance mapping function,
wherein each point on the locus is a point on a metric,
wherein the metric has a first endpoint and a second endpoint,
wherein the first endpoint is on the reference luminance mapping function,
wherein the second endpoint is on a diagonal,
wherein the locus of points depends on an adjusted maximum luminance;
applying the adapted luminance mapping function to the input luminances so as to obtain output luminances,
wherein the output image comprises the output luminances,
wherein the output image has an output maximum luminance,
wherein the output maximum luminance is different from the input maximum luminance and from the reference maximum luminance,
wherein a normalized input luma corresponds to an input luminance,
determining the adjusted maximum luminance value, wherein the determining the adjusted maximum luminance value comprises:
obtaining a surround illumination value;
obtaining a relative surround light, wherein the obtaining comprises dividing a reference illumination value by the surround illumination value;
obtaining the adjusted maximum luminance value by multiplying the output maximum luminance by the relative surround light level.