Method and apparatus for increased color accuracy of display by compensating for observer's color vision properties
Systems and methods are described for adjusting the color spectrum of synthetic objects in augmented reality (AR) displays under varying lighting conditions and a human observers spectral sensitivities, to produce customized color matches for a specific observer. Spectral data may be captured, and color matching functions (CMFs) of the observer may be used by a spectral color workflow that produces color display values, for example coordinates in RGB space. The color rendering may custom-match for multiple observers with different color perceptions under a wide range of environmental (ambient lighting) conditions.
1. A method comprising:
measuring illumination conditions of an environment;
determining an estimate of spectral illumination based upon illumination condition measurements;
determining information regarding color-matching characteristics of a user of the display;
determining spectral reflectance characteristics of at least a portion of a virtual object;
based at least in part on the spectral reflectance characteristics of the at least a portion of the virtual object, the estimate of spectral illumination and the information regarding color-matching characteristics of the user of the display, determining display color information for the at least a portion of the virtual object; and
causing display of the at least a portion of the virtual object using the display using the determined display color information for the at least a portion of the virtual object.
2. The method of claim 1 , wherein the determination of the display color is further based on the color-matching characteristics of the user of the display.
3. The method of claim 1 , wherein determining an estimate of spectral illumination comprises determining a value of an illuminating spectral radiance S(λ) for each of a plurality of wavelengths λ.
4. The method of claim 1 , wherein determining information regarding color-matching characteristics of a user of the display comprises determining an age of the user and selecting color-matching characteristics based on the user's age.
5. The method of claim 1 , wherein determining information regarding color-matching characteristics of a user of the display comprises retrieving color-matching characteristics based on a user profile.
6. The method of claim 1 , further comprising:
determining spectral radiance of at least the portion of the virtual object based on the spectral reflectance and the estimate of spectral illumination; and
based at least in part on the spectral radiance, the estimate of spectral illumination, and the information regarding color-matching characteristics of the user of the display, determining tristimulus values representing a color of at least the portion of the virtual object;
wherein the display color information is determined based at least in part on the tristimulus values.
7. The method of claim 6 , wherein the tristimulus values are L, M, and S values and wherein determining display color information comprises:
converting from the L, M, and S tristimulus values to X, Y, and Z tristimulus values; and
using a display profile to convert from the X, Y, and Z tristimulus values to RGB values.
8. The method of claim 7 , wherein the conversion from the L, M, and S tristimulus values to the X, Y, and Z tristimulus values is based in part on the color-matching characteristics of the user.
9. The method of claim 6 , wherein the determination of the display color information is performed using a display profile to convert from the tristimulus values to RGB values.
10. The method of claim 6 , wherein the tristimulus values are L, M, and S values, and wherein the color-matching characteristics comprise values of l (λ), m (λ), and s (λ) for each of a plurality of wavelengths λ.
11. The method of claim 6 , wherein the tristimulus values are X, Y, and Z values, and wherein the color-matching characteristics comprise values of x (λ), y (λ), and z (λ) for each of a plurality of wavelengths λ.
12. The method of claim 6 , wherein determining the object spectral radiance comprises determining values L(λ) of spectral radiance for each of a plurality of wavelengths λ using L(λ) =S(λ)R (λ), where S(λ) is an illuminating spectral radiance representing the estimate of spectral illumination and R(λ) is a spectral reflectance factor of the portion of the virtual object.
13. The method of claim 6 , wherein determining the spectral radiance comprises determining values L(λ) of spectral radiance for each of a plurality of wavelengths λ, wherein the tristimulus values are X, Y, and Z values, wherein the color-matching characteristics comprise values of x (λ), y (λ), and z (λ) for each of a plurality of wavelengths λ, and wherein the determination of the tristimulus values is performed using:
L=∫L (λ) l (λ) dλ, M=∫L (λ) m (λ) d λ, and S=∫L (λ) s (λ) dλ.
14. The method of claim 6 , wherein determining the spectral radiance comprises determining values L(λ) of spectral radiance for each of a plurality of wavelengths λ, wherein the tristimulus values are X, Y, and Z values, wherein the color-matching characteristics comprise values of l (λ), m (λ), and s (λ) for each of a plurality of wavelengths λ, and wherein the determination of the tristimulus values is performed using:
X=∫L (λ) x (λ) dλ, Y=∫L (λ) y (λ) d λ, and Z=∫L (λ) z (λ) dλ.
15. The method of claim 6 , wherein the tristimulus values are X, Y, and Z values and wherein determining the display color information comprises selecting a display color such that a spectral radiance L display (λ) of the display substantially satisfies
X=∫L display (λ) x (λ) dλ, Y=∫L display (λ) y (λ) d λ, and Z=∫L display (λ) z (λ) dλ.
16. The method of claim 1 , wherein the display is a see-through head-mounted display.
17. The method of claim 16 , wherein the determination of the display color is further based upon spectral transmission characteristics of the see-through display.
18. The method of claim 16 , wherein the measuring of illumination conditions comprises using a forward-facing sensor of the see-through head-mounted display.
19. A method comprising:
measuring current illumination conditions at an optical-see-through augmented-reality display;
determining a color-compensating transform for a user of the display;
determining object spectral radiance of at least a portion of a virtual object;
based at least in part on the object spectral radiance, the color-compensating transform and the current illumination conditions, determining a display color of a least a portion of the virtual object; and
displaying the virtual object on the display using the display color for the portion of the virtual object.
20. A system comprising:
a processor; and
a non-transitory computer-readable medium storing instructions operative to perform functions comprising:
measuring illumination conditions of an environment;
determining an estimate of spectral illumination based upon illumination condition measurements;
determining information regarding color-matching characteristics of a user of the display;
determining spectral reflectance characteristics of at least a portion of a virtual object;
based at least in part on the spectral reflectance characteristics of the at least a portion of the virtual object, the estimate of spectral illumination and information regarding the color-matching characteristic of the user of the display, determining display color information for the at least a portion of the virtual object; and
causing display of the at least a portion of the virtual object using the display using the determined display color information for the at least a portion of the virtual object.