System and method for adaptive tone mapping for high dynamic ratio digital images
View Patent ↗An information handling system operating an adaptive HDR tone mapping system may comprise a display screen including a plurality of pixels operating at a lower dynamic range of brightness values, a graphics processor executing code instructions to prepare data of an HDR digital image for display at the lower dynamic range, to determine a relative brightness ratio comparing a number of pixels in the data for the image to display at a brightness level below a typical display brightness and at or above the typical display brightness, and to generate a tone map to modify the data of the image if the relative brightness ratio does not meet or exceed a preset threshold such that the pixels are mapped to a maximum brightness of a peaking display brightness level of the display screen, and the display screen displaying the plurality of pixels according to the first adaptive tone map modification.
1. An information handling system operating an adaptive high dynamic range (HDR) tone mapping system comprising:
a display screen including a plurality of pixels operating at a lower dynamic range of brightness values wherein a peaking display brightness value is below a maximum brightness value within data for an HDR digital image;
a graphics processor operably connected to the plurality of pixels executing code instructions of the adaptive HDR tone mapping system to receive data for an HDR digital image and prepare the HDR digital image for display at the lower dynamic range of brightness values;
the graphics processor to determine a relative brightness ratio comparing a number of a first plurality of pixels in the data for the HDR digital image to display at a brightness level below a typical display brightness of the display screen to a number of a second plurality of pixels in the data for the HDR digital image to display at or above the typical display brightness of the display screen;
the graphics processor to generate a first adaptive tone map to modify the data of the HDR digital image if the relative brightness ratio does not meet or exceed a preset relative brightness threshold such that the first plurality of pixels will display in the lower dynamic range of brightness values and the second plurality of pixels are mapped to a clipped brightness level equivalent to the peaking display brightness level of the display screen; and
the display screen displaying the first plurality of pixels and the second plurality of pixels of the HDR digital image within the lower dynamic range of brightness values, according to the first adaptive tone map modification.
2. The information handling system of claim 1 further comprising:
the graphics processor to generate a second adaptive tone map to modify the data of the HDR digital image if the relative brightness ratio meets or exceeds the preset relative brightness threshold such that the first plurality of pixels and the second plurality of pixels are compressed to fit within the lower dynamic range of brightness values for display at or below the peaking display brightness level value of the display screen.
3. The information handling system of claim 2 further comprising:
the graphics processor to identify a range of high brightness values at or above the peaking display brightness value of the display screen in the data for the HDR digital image and partition the range of high brightness values into a plurality of high brightness value subranges;
the graphics processor to determine a number of pixels with brightness values within a first of the high brightness value subranges;
the graphics processor to determine a subrange compression factor between the number of the plurality of pixels within the first of the high brightness value subranges and the number of pixels exceeding the typical display brightness value in the data for the HDR image; and
the graphics processor to generate the second adaptive tone map to apply a degree of compression for the first of the high brightness value subranges in accordance with the corresponding subrange compression factor.
4. The information handling system of claim 1 , wherein lower dynamic range of brightness values is a standard dynamic range (SDR) of brightness values.
5. The information handling system of claim 1 , wherein the relative brightness ratio is determined using a histogram analysis of data for the HDR digital image.
6. The information handling system of claim 1 , wherein the preset relative brightness threshold is equivalent to 10%.
7. The information handling system of claim 1 , wherein the typical display brightness is 400 candelas per meter squared.
8. A method for adaptively generating a high dynamic range (HDR) tone map comprising:
receiving data for an HDR digital image and preparing via a graphics processor the HDR digital image for display at a lower dynamic range of brightness values on a display device having a lower operable dynamic range than the HDR digital image data;
determining via the graphics processor a relative brightness ratio comparing a number of a first plurality of pixels in the data for the HDR digital image to display at a brightness level below a typical display brightness of the display screen to a number of a second plurality of pixels in the data for the HDR digital image to display at or above the typical display brightness of the display screen;
generating via the graphics processor a first adaptive tone map to modify the data of the HDR digital image if the relative brightness ratio does not meet or exceed a preset relative brightness threshold such that the first plurality of pixels will display in the lower dynamic range of brightness values and the second plurality of pixels are mapped to a clipped brightness level equivalent to a peaking display brightness level of the display screen; and
displaying via the display screen the first plurality of pixels and the second plurality of pixels of the HDR digital image within the lower dynamic range of brightness values, according to the first adaptive tone map modification of the HDR digital image data.
9. The method of claim 8 further comprising:
generating via the graphics processor a second adaptive tone map to modify the data of the HDR digital image if the relative brightness ratio meets or exceeds the preset relative brightness threshold such that the first plurality of pixels and the second plurality of pixels are compressed to fit within the lower dynamic range of brightness values for display at or below the peaking display brightness level value of the display screen.
10. The method of claim 8 further comprising:
identifying, via the graphics processor, a range of high brightness values at or above the peaking display brightness value of the display screen in the data for the HDR digital image and partitioning the range of high brightness values into a plurality of high brightness value subranges if the relative brightness ratio meets or exceeds the preset relative brightness threshold;
determining via the graphics processor a number of pixels with brightness values within a first of the high brightness value subranges;
determining via the graphics processor a subrange compression factor between the number of the plurality of pixels within the first of the high brightness value subranges and the number of pixels exceeding the typical display brightness value in the data for the HDR image; and
generating via the graphics processor the second adaptive tone map to apply a degree of compression for the first of the high brightness value subranges in accordance with the corresponding subrange compression factor.
11. The method of claim 8 , wherein lower dynamic range of brightness values is a standard dynamic range (SDR) of brightness values.
12. The method of claim 8 , wherein the relative brightness ratio is determined using a histogram analysis of the HDR digital image.
13. The method of claim 8 , wherein the preset relative brightness threshold is equivalent to 80%.
14. The method of claim 8 , wherein the typical display brightness is 400 candelas per meter squared.
15. An information handling system operating an adaptive high dynamic range (HDR) tone mapping system comprising:
a display screen including a plurality of pixels operating at a lower dynamic range of brightness values wherein a peaking display brightness value is below a maximum brightness value within data for an HDR digital image;
a graphics processor operably connected to the plurality of pixels executing code instructions of the adaptive HDR tone mapping system to receive data for an HDR digital image and prepare the HDR digital image for display at the lower dynamic range of brightness values;
the graphics processor to determine a relative brightness ratio comparing a number of a first plurality of pixels in the data for the HDR digital image to display at a brightness level below a typical display brightness of the display screen to a number of a second plurality of pixels in the data for the HDR digital image to display at or above the typical display brightness of the display screen,
the graphics processor to generate a first adaptive tone map to modify the data of the HDR digital image if the relative brightness ratio does not meet or exceed a preset relative brightness threshold such that the first plurality of pixels will display in the lower dynamic range of brightness values and the second plurality of pixels are mapped to a clipped brightness level equivalent to the peaking display brightness level of the display screen;
the graphics processor to generate a second adaptive tone map to modify the data of the HDR digital image if the relative brightness ratio meets or exceeds the preset relative brightness threshold such that the first plurality of pixels and the second plurality of pixels are compressed to fit within the lower dynamic range of brightness values for display at or below the peaking display brightness level value of the display screen; and
the display screen displaying the first plurality of pixels and the second plurality of pixels of the HDR digital image within the lower dynamic range of brightness values, according to the generation of the first adaptive tone map or the second adaptive tone map.
16. The information handling system of claim 15 further comprising:
the graphics processor to identify a range of high brightness values at or above a peaking display brightness value of the display screen in the data for the HDR digital image and partition the range of high brightness values into a plurality of high brightness value subranges when the second adaptive tone map is generated;
the graphics processor to determine a number of pixels with brightness values within a first of the high brightness value subranges;
the graphics processor to determine a subrange compression factor between the number of the plurality of pixels within the first of the high brightness value subranges and the number of pixels exceeding the typical display brightness value in the data for the HDR image; and
the graphics processor to generate the second adaptive tone map to apply a degree of compression for the first of the high brightness value subranges in accordance with the corresponding subrange compression factor.
17. The information handling system of claim 15 , wherein the typical display brightness of the display screen is 300 candelas per meter squared.
18. The information handling system of claim 15 , wherein the peaking display brightness of the display screen is 400 candelas per meter squared.
19. The information handling system of claim 15 , wherein lower dynamic range of brightness values is a standard dynamic range (SDR) of brightness values.
20. The information handling system of claim 15 , wherein the peaking display brightness of the display screen is 600 candelas per meter squared.