Controlling characteristics of light output from LED walls
A computer-generated scene is generated as background for a live action set, for display on a panel of light emitting diodes (LEDs). Characteristics of light output by the LED panel are controlled such that the computer-generated scene rendered on the LED panel, when captured by a motion picture camera, has high fidelity to the original computer-generated scene. Consequently, the scene displayed on the screen more closely simulates the rendered scene from the viewpoint of the camera. Thus, a viewpoint captured by the camera appears more realistic and/or truer to the creative intent.
1. A method for controlling individual pixels of an electronic display screen displaying an input image, the method comprising:
receiving, by at least one processor, an output image from a camera capturing the display screen;
estimating, by the at least one processor, a difference in perceptual aspect between each of one or more pixels of the output image and each of one or more correlated pixels of the input image based on a geometric relation between the camera and the one or more correlated pixels of the input image, the geometric relation including an angular offset between the camera and the one or more correlated pixels; and
in response to the difference being greater than a threshold, adjusting, by the at least one processor, at least one parameter for controlling display of the input image on the electronic display screen by an amount calculated, for each of the one or more correlated pixels of the input image, to reduce the difference.
2. The method of claim 1 , wherein the one or more correlated pixels of the input image are correlated to the one or more pixels of the output image based on correlating clusters of adjacent pixels of the output image to corresponding clusters of adjacent pixels of the input image.
3. The method of claim 1 , wherein the geometric relation is further determined based on a current camera position and orientation relative to the display screen.
4. The method of claim 3 , further comprising determining the camera position and orientation based on at least one of a predefined plan for motion of the camera, or sensor data indicating position and orientation of the camera.
5. The method of claim 3 , wherein the geometric relation is a smooth function across neighboring pixels.
6. The method of claim 1 , wherein estimating the difference comprises looking up the difference in perceptual aspect based at least in part on the angular offset.
7. The method of claim 1 , wherein estimating the difference comprises calculating the difference in perceptual aspect based on a continuous function of the angular offset.
8. The method of claim 1 , wherein the at least one parameter comprises luminosity.
9. The method of claim 1 , wherein adjusting the at least one parameter further comprises optimizing brightness of the display while preventing unintended variance between adjacent pixels from exceeding a perceptual threshold.
10. The method of claim 1 , wherein the receiving, estimating, and adjusting are performed separately for at least two cameras imaging the display screen at separate instants by synchronized camera shutters.
11. The method of claim 1 , wherein the receiving, estimating, and adjusting are performed asynchronously with the camera capturing the display screen, and the at least one processor receives the output image from an electronic memory.
12. The method of claim 11 , wherein the electronic memory is coupled to the camera via a computer network.
13. The method of claim 1 , wherein the angular offset is calculated in real time using a real-time camera motion tracking system.
14. The method of claim 1 , wherein adjusting the at least one parameter includes determining a color attenuation factor associated with the one or more correlated pixels of the input image.
15. The method of claim 1 , wherein individual pixels of the one or more pixels of the output image are correlated to corresponding individual pixels of the one or more correlated pixels of the input image based on at least one of a: one to one, one to many, or many to one basis.
16. An apparatus for controlling individual pixels of an electronic display screen displaying an input image, the apparatus comprising:
at least one memory storing processor-readable instructions;
at least one processor configured to access the at least one memory and execute the processor-readable instructions to perform operations, the operations comprising:
receiving an output image from a camera capturing the display screen;
estimating a difference in perceptual aspect between each of one or more pixels of the output image and each of one or more correlated pixels of the input image based on a geometric relation between the camera and the one or more correlated pixels of the input image, the geometric relation including an angular offset between the camera and the one or more correlated pixels; and
in response to the difference being greater than a threshold, adjusting at least one parameter for controlling display of the input image on the electronic display screen by an amount calculated, for each of the one or more correlated pixels of the input image, to reduce the difference.
17. The apparatus of claim 16 , wherein the geometric relation between the camera and one or more correlated pixels is further determined based on a current camera position and orientation relative to the display screen.
18. The apparatus of claim 16 , wherein adjusting the at least one parameter includes optimizing a brightness of the display while preventing unintended variance between adjacent pixels from exceeding a perceptual threshold.
19. The apparatus of claim 16 , wherein the angular offset is calculated in real time using a real-time camera motion tracking system.
20. The apparatus of claim 16 , wherein adjusting the at least one parameter includes determining a color attenuation factor associated with the one or more correlated pixels of the input image.