Color correction for XR display
Display systems, media, and methods. Pixels of an image former form an image. Each pixel has a first color element to propagate a first amount of a first light having a first wavelength, based on a first electrical stimulus, and a second color element to propagate a second amount of a second light having a second wavelength, based on a second electrical stimulus. A display surface presents the image across a plurality of display surface locations. A processor executes instructions to scale the first electrical stimulus of each pixel of the image former by a first light scale factor, scale the second electrical stimulus of each pixel of the image former by a second light scale factor, and apply a pixel shading map to the image former to independently adjust, for each pixel of the display, the first amount relative to the second amount.
1 . A display system, comprising:
at least one display comprising:
an image former comprising a plurality of pixels configured to form an image, each pixel comprising:
a first color element configured to propagate a first amount of a first light having a first wavelength, the first amount being based on a first electrical stimulus applied to the first color element; and
a second color element configured to propagate a second amount of a second light having a second wavelength, the second amount being based on a second electrical stimulus applied to the second color element; and
a display surface configured to present the image across a plurality of virtual image surface locations;
at least one processor; and
a memory storing instructions that, when executed by the at least one processor, configure the display system to perform operations comprising:
scaling the first electrical stimulus of each pixel of the image former by a first light scale factor;
scaling the second electrical stimulus of each pixel of the image former by a second light scale factor; and
applying at least one pixel shading map to the image former to independently adjust, for each pixel of the display, the first amount relative to the second amount,
wherein:
the first light scale factor, the second light scale factor, and the at least one pixel shading map are generated by:
measuring, for each virtual image surface location of a plurality of virtual image surface locations presented by a test display surface of a test display device, an amount of the first light and an amount of the second light presented from the test display surface location; and
defining the first light scale factor, the second light scale factor, and the at least one pixel shading map to increase uniformity of the amounts of the first light and second light presented across the plurality of virtual image surface locations.
2 . The display system of claim 1 , wherein:
the at least one display comprises a waveguide configured to present the image from the plurality of virtual image surface locations.
3 . The display system of claim 1 , wherein:
the image former comprises at least one liquid crystal on silicon panel configured to propagate the first light and second light of each pixel through reflection.
4 . The display system of claim 1 , wherein:
the image former comprises an array of light emitting diodes configured to emit the first light and second light of each pixel.
5 . The display system of claim 1 , wherein:
the at least one pixel shading map comprises a look up table comprising pixel shading values for the plurality of pixels.
6 . The display system of claim 1 , wherein:
the defining of the first light scale factor, the second light scale factor, and the at least one pixel shading map to increase the uniformity of the amounts of the first light and second light presented across the plurality of virtual image surface locations comprises:
defining the first light scale factor, the second light scale factor, and the at least one pixel shading map to reduce a color non-uniformity measure, the color non-uniformity measure being based at least in part on a monocular non-uniformity measure representative of a difference, across the plurality of virtual image surface locations, between:
the measured amounts of the first light and second light; and
a white-balanced target distribution of first light and second light.
7 . The display system of claim 6 , wherein:
the color non-uniformity measure is based at least in part on a smoothness measure representative of a total variation in the measured amounts of the first light and second light across the plurality of virtual image surface locations.
8 . The display system of claim 7 , wherein:
the at least one display comprises:
a left near eye display having a left image former and a left display surface configured to present the image from a plurality of left virtual image surface locations; and
a right near eye display having a right image former and a right display surface configured to present the image from a plurality of right virtual image surface locations;
the at least one pixel shading map comprises:
a left pixel shading map for the image former of the left near eye display; and
a right pixel shading map for the image former of the right near eye display;
the measuring is performed for a test left near eye display and a test right near eye display of the test display device; and
the color non-uniformity measure is based at least in part on a binocular rivalry measure representative of, for each of the plurality of left virtual image surface locations and corresponding right virtual image surface locations:
a difference in the amounts of the first light presented by the test left near eye display and the test right near eye display at the virtual image surface location; and
a difference in the amounts of the second light presented by the test left near eye display and the test right near eye display at the virtual image surface location.
9 . A method for color correction of a display system, comprising:
measuring, for each virtual image surface location of a plurality of virtual image surface locations presented by a test display surface of a test display device, an amount of a first light having a first wavelength and an amount of a second light having a second wavelength presented from the virtual image surface location;
defining a first light scale factor, a second light scale factor, and at least one pixel shading map to increase uniformity of the amounts of the first light and second light presented across the plurality of virtual image surface locations;
forming an image by, at each pixel of a plurality of pixels of a display of the display system:
propagating a first amount of the first light from a first color element of the pixel, the first amount being based on a first electrical stimulus applied to the first color element; and
propagating a second amount of the second light from a second color element of the pixel, the second amount being based on a second electrical stimulus applied to the second color element;
presenting the image across a plurality of virtual image surface locations by propagating light from a display surface of the display;
scaling the first electrical stimulus of each pixel of the image former by the first light scale factor;
scaling the second electrical stimulus of each pixel of the image former by the second light scale factor; and
applying the at least one pixel shading map to the plurality of pixels to independently adjust, for each pixel, the first amount relative to the second amount.
10 . The method of claim 9 , wherein:
the display surface comprises a surface of a waveguide, the waveguide being configured to present the image from the plurality of virtual image surface locations.
11 . The method of claim 9 , wherein:
the plurality of pixels comprises at least one liquid crystal on silicon panel configured to propagate the first light and second light of each pixel through reflection.
12 . The method of claim 9 , wherein:
the plurality of pixels comprises at least one array of light emitting diodes configured to emit the first light and second light of each pixel.
13 . The method of claim 9 , wherein:
the at least one pixel shading map comprises a look up table comprising pixel shading values for the plurality of pixels.
14 . The method of claim 9 , wherein:
the defining of the first light scale factor, the second light scale factor, and the at least one pixel shading map to increase the uniformity of the amounts of the first light and second light presented across the plurality of virtual image surface locations comprises:
defining the first light scale factor, the second light scale factor, and the at least one pixel shading map to reduce a color non-uniformity measure, the color non-uniformity measure being based at least in part on a monocular non-uniformity measure representative of a difference, across the plurality of virtual image surface locations, between:
the measured amounts of the first light and second light; and
a white-balanced target distribution of first light and second light.
15 . The method of claim 14 , wherein:
the color non-uniformity measure is based at least in part on a smoothness measure representative of a total variation in the measured amounts of the first light and second light across the plurality of virtual image surface locations.
16 . The method of claim 15 , wherein:
the display is a left near eye display;
the display system comprises the left near eye display and a right near eye display;
the measuring is performed for a test left near eye display and a test right near eye display of the test display device; and
the color non-uniformity measure is based at least in part on a binocular rivalry measure representative of, for each of a plurality of left virtual image surface locations of the test left near eye display and corresponding right virtual image surface locations of the test right near eye display:
a difference in the amounts of the first light presented by the test left near eye display and the test right near eye display at the virtual image surface location; and
a difference in the amounts of the second light presented by the test left near eye display and the test right near eye display at the virtual image surface location.
17 . A method for generating color correction settings for a display system, comprising:
measuring, for each virtual image surface location of a plurality of virtual image surface locations presented by a test display surface of a test display device, an amount of a first light having a first wavelength and an amount of a second light having a second wavelength presented from the virtual image surface location; and
defining a first light scale factor, a second light scale factor, and at least one pixel shading map to increase uniformity of the amounts of the first light and second light presented across the plurality of virtual image surface locations,
the first light scale factor being configured to scale a first electrical stimulus of each pixel of an image former of the display system to modulate an amount of the first light propagated by the pixel;
the second light scale factor being configured to scale a second electrical stimulus of each pixel of the image former to modulate an amount of the second light propagated by the pixel; and
the at least one pixel shading map configured to independently adjust, for each pixel of the image former, the amount of the first light relative to the amount of the second light.
18 . The method of claim 17 , wherein:
the measuring is performed for a test left near eye display and a test right near eye display of the test display device; and
the defining of the first light scale factor, the second light scale factor, and the at least one pixel shading map to increase the uniformity of the amounts of the first light and second light presented across the plurality of virtual image surface locations comprises:
defining the first light scale factor, the second light scale factor, and the at least one pixel shading map to reduce a color non-uniformity measure, the color non-uniformity measure being based at least in part on:
a monocular non-uniformity measure representative of a difference, across the plurality of virtual image surface locations, between:
the measured amounts of the first light and second light; and
a white-balanced target distribution of first light and second light;
a smoothness measure representative of a total variation in the measured amounts of the first light and second light across the plurality of virtual image surface locations; and
a binocular rivalry measure representative of, for each of the plurality of left virtual image surface locations of the test left near eye display and corresponding right virtual image surface locations of the test right near eye display:
a difference in the amounts of the first light presented by the test left near eye display and the test right near eye display at the virtual image surface location; and
a difference in the amounts of the second light presented by the test left near eye display and the test right near eye display at the virtual image surface location.
19 . The method of claim 17 , wherein:
the display system comprises a waveguide configured to present the image from the plurality of virtual image surface locations.
20 . The method of claim 17 , wherein:
the at least one pixel shading map comprises a look up table comprising pixel shading values for individual pixels of the image former.