Interactive depth of field using simulated heat diffusion

• US 7,787,688 B1
• Filed: 01/25/2007
• Issued: 08/31/2010
• Est. Priority Date: 01/25/2006
• Status: Active Grant

• Current Assignee: Pixar (The Walt Disney Company)
• Original Assignee: Pixar (The Walt Disney Company)
• Inventors: Kass, Michael
• Primary Examiner(s): Chawan; Sheela C
• Application Number:
  US11/698,484
• Time in Patent Office: 1,314 Days
• Field of Search: 382/100, 382/154, 382/111, 382/162, 382/275, 382/261, 382/276, 382/260, 382/263, 382/274, 382/264, 703/5, 703/6, 358/471, 358/518, 358/403, 358/527, 358/448, 399/166, 399/314, 430/204, 430/218, 430/487, 430/244, 430/494, 348/761, 348/739, 348/744, 348/759, 348/760, 348/241, 359/252, 359/237, 359/238, 359/240, 359/245, 359/246, 345/589
• US Class Current: 382/154
• CPC Class Codes: G06T 15/00 3D [Three Dimensional] image rendering

Abstract

A computer-implemented method for generating depth-of-field effects includes receiving information specifying an input image rendered using a pinhole camera. A first set of circles of confusion associated with portions of the input image are determined based a set of parameters associated with the pinhole camera. The first set of circles of confusion are then associated with heat conductivity of a medium. The portions of the input image are blurred according to heat diffusion in the medium to generate a first output image having a first depth-of-field effect.

Claims

1. A method for generating depth-of-field effects, the method comprising:

receiving a first image comprising a value at each point of the first image;

receiving a second image indicative of a first circle of confusion at each point of the first image; and

generating a third image in response to simulating heat diffusion using an implicit solution to a heat equation using an initial heat for the heat equation based on the value at each point of the first image and thermal conductivity for the heat equation based on the first circle of confusion at each point of the first image.

2. The method of claim 1 further comprising:

receiving a fourth image indicative of depth at each point of the first image; and

generating the second image based the depth of each point provided by the fourth image and one or more parameters associated with a camera used to render the first image.

3. The method of claim 1 wherein the implicit solution to the heat equation comprises an alternating direction implicit method.

4. The method of claim 3 wherein the alternating direction implicit method comprises two or more directions.

5. The method of claim 3 wherein the alternating direction implicit method comprises:

determining, along a first direction associated with the first image, heat diffusion in response to a first convolution; and

determining, along a second direction orthogonal to the first direction of the first image, distribution of heat based on the heat diffusion along the first direction in response to a second convolution.

6. The method of claim 3 wherein generating the third image in response to simulating heat diffusion using the alternating direction implicit method to the heat equation comprises generating the third image using cyclic reduction.

7. The method of claim 6 further comprising generating the third image using a GPU.

8. The method of claim 1 further comprising:

determining one or more layers associated with the first image;

simulating heat diffusion using the implicit solution to the heat equation to blur one or more of the layers associated with the first image; and

compositing the blurred one or more layers.

9. The method of claim 8 wherein the one or more layers includes a background layer.

10. The method of claim 8 wherein the one or more layers includes a foreground layer.

11. A computer program product stored on a non-transitory computer readable medium for generating depth-of-field effects, the computer program product comprising:

code for receiving a first image comprising a value at each point of the first image;

code for receiving a second image indicative of a first circle of confusion at each point of the first image; and

code for generating a third image in response to simulating heat diffusion using an implicit solution to a heat equation using an initial heat for the heat equation based on the value at each point of the first image and thermal conductivity for the heat equation based on the first circle of confusion at each point of the first image.

12. The computer program product of claim 11 further comprising:

code for receiving a fourth image indicative of depth at each point of the first image; and

code for generating the second image based the depth of each point provided by the fourth image and one or more parameters associated with a camera used to render the first image.

13. The computer program product of claim 11 further comprising code for generating the implicit solution to the heat equation using alternating direction implicit method.

14. The computer program product of claim 13 wherein the alternating direction implicit method comprises two or more directions.

15. The computer program product of claim 13 further comprising:

code for determining, along a first direction associated with the first image, heat diffusion in response to a first convolution; and

code for determining, along a second direction orthogonal to the first direction of the first image, distribution of heat based on the heat diffusion along the first direction in response to a second convolution.

16. The computer program product of claim 11 wherein the code for generating the third image in response to simulating heat diffusion using the alternating direction implicit method to the heat equation comprises code for generating the third image using cyclic reduction.

17. The computer program product of claim 16 further comprising code for generating the third image using a GPU.

18. The computer program product of claim 11 further comprising:

code for determining one or more layers associated with the first image;

code for simulating heat diffusion using the implicit solution to the heat equation to blur one or more of the layers associated with the first image; and

code for compositing the blurred one or more layers.

19. A system for generating depth-of-field effects, the system comprising:

a processor; and

a memory coupled to the processor, the memory configured to store a set of instructions which when executed by the processor cause the processor to;

receive a first image comprising a value at each point of the first image;

receive a second image indicative of a first circle of confusion at each point of the first image; and

generate a third image in response to simulating heat diffusion using an implicit solution to a heat equation using an initial heat for the heat equation based on the value at each point of the first image and thermal conductivity for the heat equation based on the first circle of confusion at each point of the first image.

20. The system of claim 19 wherein the processor is caused to:

receive a fourth image indicative of depth at each point of the first image; and

generate the second image based the depth of each point provided by the fourth image and one or more parameters associated with a camera used to render the first image.

21. The system of claim 19 wherein the processor is caused to generate the implicit solution to the heat equation using alternating direction implicit method.

22. The system of claim 21 wherein the processor is caused to:

determine, along a first direction associated with the first image, heat diffusion in response to a first convolution; and

determine, along a second direction orthogonal to the first direction of the first image, distribution of heat based on the heat diffusion along the first direction in response to a second convolution.

23. The system of claim 19 wherein the processor is caused to generate the third image using cyclic reduction.

24. The system of claim 23 wherein the processor is caused to generate the third image using a GPU.

25. The system of claim 19 wherein the processor is caused to:

determine one or more layers associated with the first image;

simulate heat diffusion using the implicit solution to the heat equation to blur one or more of the layers associated with the first image; and

composite the blurred one or more layers.