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MATLAB implementation of the Perez physically-based sky model.
Matlab
branch: master

Performing optimization on camera zenith angle instead of horizon line.

Avoids problems with camera is looking close to zenith (horizon line is at infinity!). Can be converted back and forth anyway.
latest commit acd98f932b
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.gitignore
LICENSE.txt
README.txt Fixed bad characters in README file.
convertTurbidityToSkyParams.m
exactGradientModel.m
exactGradientModelRatio.m
exactSkyModel.m
exactSkyModelRatio.m
exactSunModel.m
getTurbidityMapping.m
perezGradientModel.m
perezSkyModel.m
perezSunModel.m
pixelAzimuthAngle.m First commit from code online.
pixelZenithAngle.m
reconstructSkyFromFullModel.m
setPath.m
synthesizeSky.m

README.txt

This is a MATLAB implementation of the Perez sky model [1] that we've 
re-parameterized as a function of common camera parameters, as explained in 
our IJCV 2010 paper [2].

See the following website for more information:

http://graphics.cs.cmu.edu/projects/sky/


=== TEST FILE ===

Use the file 'synthesizeSky.m' as a starting point. 


=== SKY MODEL ===

These files synthesize the sky model based on camera parameters as inputs:
- exactSkyModel.m: Synthesizes the full sky model;
- exactGradientModel.m: Synthesizes only the "gradient" part of the sky model;
- exactSunModel.m: Synthesizes only the "sun" part of the sky model.

These files synthesize the sky model based on angles as inputs (Perez sky model):
- perezSkyModel.m: Synthesizes the full sky model;
- perezGradientModel.m: Synthesizes only the "gradient" part of the sky model;
- perezSunModel.m: Synthesizes only the "sun" part of the sky model.

Useful files that convert from pixel coordinates to angles:
- pixelAzimuthAngle.m: Converts from pixels to azimuth angle;
- pixelZenithAngle.m: Converts from pixels to zenith angle.


=== TURBIDITY ===

These files deal with converting the turbidity to the Perez weather 
coefficients (in 3 channels in xyY color space, as in [3]):

- convertTurbidityToSkyParams.m: Converts turbidity to the weather 
  coefficients;
- getTurbidityMapping.m: Returns the turbidity mapping between the weather 
  coefficients in each channel.

=== REFERENCES ===

[1]	R. Perez, R. Seals, and J. Michalsky, "All-weather model for sky 
luminance distribution -- preliminary configuration and validation," Solar 
Energy, vol. 50, no. 3, pp. 235--245, Mar. 1993.

[2]	J.-F. Lalonde, S. G. Narasimhan, and A. A. Efros, "What do the sun and 
the sky tell us about the camera?," International Journal of Computer
Vision, vol. 88, no. 1, pp. 24--51, May 2010.

[3]	A. J. Preetham, P. Shirley, and B. Smits, "A practical analytic model 
for daylight," presented at the Proceedings of ACM SIGGRAPH 1999, 1999.


=== CHANGELOG ===

09/18/12: Now using github! See commit messages for changelogs. 
09/21/11: Added missing file 'exactGradientModelRatio.m'. Thanks to A. 
Ravichandran for pointing this out!
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