Combining Spherical Harmonics and Point-Source Illumination for Efficient Image-Based Relighting (bibtex)
by Borom Tunwattanapong, Abhijeet Ghosh, Paul Debevec
Abstract:
Traditional image-based relighting technique requires capturing a dense set of lighting directions surrounding the object and uses the linearity of light transport property together with the illumina- tion data of the target environment to relight an object [Debevec et al. 2000]. However, this can be a very data intensive process because such datasets typically involve photographing hundreds of lighting directions. It is also difficult to modify or edit the data in post-production environments because the data is high dimen- sional. Adjustment has to be made in several dimensions in order to add artistic effects to the result. Difficulty in acquisition pro- cess is also one of the main problems. The capturing process typi- cally lasts long enough to only be suitable for static objects. In this poster, we present a relighting technique which greatly reduces the number of images required for relighting, and still generate real- istic results. We combine spherical harmonics with point lights to achieve efficient image based relighting. Spherical harmonics can efficiently capture smooth low frequency illumination [Ramamoor- thi and Hanrahan 2001] while point lights capture high frequency directional illumination. Combining both techniques, we create re- lighting results which have both low and high frequency illumi- nation data. This technique also benefits the acquisition process by reducing the number of required photographs which results in shorter capture time. In addition, fewer dimensions of the data can potentially simplify modification or editing of reflectance data.
Reference:
Combining Spherical Harmonics and Point-Source Illumination for Efficient Image-Based Relighting (Borom Tunwattanapong, Abhijeet Ghosh, Paul Debevec), In SIGGRAPH 2010, 2010.
Bibtex Entry:
@inproceedings{tunwattanapong_combining_2010,
	title = {Combining {Spherical} {Harmonics} and {Point}-{Source} {Illumination} for {Efficient} {Image}-{Based} {Relighting}},
	url = {http://ict.usc.edu/pubs/Combining%20Spherical%20Harmonics%20and%20Point-Source%20Illumination%20for%20Efficient%20Image-Based%20Relighting.pdf},
	abstract = {Traditional image-based relighting technique requires capturing a dense set of lighting directions surrounding the object and uses the linearity of light transport property together with the illumina- tion data of the target environment to relight an object [Debevec et al. 2000]. However, this can be a very data intensive process because such datasets typically involve photographing hundreds of lighting directions. It is also difficult to modify or edit the data in post-production environments because the data is high dimen- sional. Adjustment has to be made in several dimensions in order to add artistic effects to the result. Difficulty in acquisition pro- cess is also one of the main problems. The capturing process typi- cally lasts long enough to only be suitable for static objects. In this poster, we present a relighting technique which greatly reduces the number of images required for relighting, and still generate real- istic results. We combine spherical harmonics with point lights to achieve efficient image based relighting. Spherical harmonics can efficiently capture smooth low frequency illumination [Ramamoor- thi and Hanrahan 2001] while point lights capture high frequency directional illumination. Combining both techniques, we create re- lighting results which have both low and high frequency illumi- nation data. This technique also benefits the acquisition process by reducing the number of required photographs which results in shorter capture time. In addition, fewer dimensions of the data can potentially simplify modification or editing of reflectance data.},
	booktitle = {{SIGGRAPH} 2010},
	author = {Tunwattanapong, Borom and Ghosh, Abhijeet and Debevec, Paul},
	year = {2010},
	keywords = {Graphics}
}
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