Appearance manifolds for modeling time-variant appearance of materials

1. A method for modeling a time-variant appearance of a material sample, comprising:

employing a processor that executes instructions retained in a computer-memory, the instructions when executed by the processor implement at least the following operations:

performing a sample analysis of the material sample, wherein the sample analysis orders surface points of the material sample with respect to weathering from data captured at a single instant in time; and

performing an appearance synthesis using the sample analysis, wherein the appearance synthesis generates a time-variant sequence of frames for weathering an object.

2. The method of claim 1 wherein performing the sample analysis includes:

constructing an appearance manifold from the data captured at the single instant in time, wherein the appearance manifold approximates the underlying subspace of weathered surface point appearances of the material sample.

3. The method of claim 2 , further comprising:

annotating, by a user, a set of most weathered and a set of least weathered surface points in the appearance manifold.

4. The method of claim 3 , further comprising:

constructing a weathering degree map from the annotated appearance manifold, wherein the weathering degree map describes variations in weathering degree over the material sample.

5. The method of claim 4 wherein performing the appearance synthesis includes:

computing a source level map from the weathering degree map.

6. The method of claim 5 wherein the time-variant sequence of frames is generated from target weathering level maps, the weathering degree map, the material sample, and the source level map.

7. The method of claim 6 wherein generating the time variant sequence of frames includes:

initializing the appearance of each frame from the appearance of the preceding frame;

incorporating appearance values from patches of the material sample; and

refining the initial appearance frame by synthesis from multiple neighborhood scales.

8. The method of claim 7 wherein the appearance synthesis is performed on key frames and the appearance of the intermediate frames between the key frames are interpolated, wherein the appearance of each pixel in an intermediate frame is interpolated along the shortest path in the appearance manifold between the corresponding pixels in the preceding and subsequent key frames.

9. The method of claim 1 , further comprising:

weathering of an input, wherein the input includes at least one of an input weathered object or an input image; and

deweathering of the input.

10. The method of claim 9 wherein weathering and deweathering is performed in response to inputs received at a user tool.

11. The method of claim 1 , further comprising:

transferring the weathering of the material from the object to another object.

12. One or more computer readable media, having computer-readable instructions recorded thereon that, when executed by one or more processors, perform operations comprising:

performing a sample analysis of a material, wherein the sample analysis orders surface points of the material relative with respect to weathering from data captured at a single instant in time; and

performing an appearance synthesis using the sample analysis, wherein the appearance synthesis generates a time-variant sequence of frames for weathering an object.

13. The one or more computer storage media of claim 12 wherein performing the sample analysis includes:

constructing an appearance manifold from the data captured at the single instant in time, wherein the appearance manifold approximates the underlying subspace of weathered surface point appearances of the material.

14. The one or more computer storage media of claim 13 , wherein the computer readable instructions when executed by the one or more processors further perform operations comprising:

receiving input that annotates a set of most weathered and a set of least weathered surface points in the appearance manifold; and

constructing a weathering degree map from the annotated appearance manifold, wherein the weathering degree map describes variations in weathering degree over the material.

15. The one or more computer storage media of claim 12 wherein generating the time variant sequence of frames includes:

initializing the appearance of each frame from the appearance of the preceding frame;

incorporating appearance values from patches of the material; and

refining the initial appearance frame by synthesis from multiple neighborhood scales.

16. The one or more computer storage media of claim 15 wherein the synthesis is performed on key frames and intermediate frames between the key frames are interpolated, wherein the appearance of each pixel in an intermediate frame is interpolated along the shortest path in the appearance manifold between the corresponding pixels in the preceding and subsequent key frames.

17. The one or more computer storage media of claim 12 wherein the time-variant sequence of frames is synthesized onto a 3-dimensional object.

18. A system, comprising:

one or more processing units; and

one or more computer readable media communicatively coupled to the processing unit, the one or more computer readable media having stored computer readable instructions that when executed by the one or more processing units perform operations comprising:

performing a sample analysis of a material, wherein the sample analysis orders surface points of the material with respect to weathering from data captured at a single instant in time; and

performing an appearance synthesis using the sample analysis, wherein the appearance synthesis generates a time-variant sequence of frames for weathering an object.

19. The system of claim 18 wherein performing the sample analysis further includes:

constructing an appearance manifold from the data captured at the single instant in time, wherein the appearance manifold approximates the underlying intrinsic structure of weathered surface point appearances of the material;

receiving input that annotates a set of most weathered and a set of least weathered surface points in the appearance manifold; and

constructing a weathering degree map from the annotated appearance manifold, wherein the weathering degree map describes variations in weathering degree over the material.

20. The system of claim 18 wherein generating the time variant sequence of frames includes:

initializing the appearance of each frame from the appearance of the preceding frame;

incorporating appearance values from patches of the material; and

refining the initial appearance frame by synthesis from multiple neighborhood scales.