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Deep Compositing Using Lie Algebras

Published: 01 June 2017 Publication History

Abstract

Deep compositing is an important practical tool in creating digital imagery, but there has been little theoretical analysis of the underlying mathematical operators. Motivated by finding a simple formulation of the merging operation on OpenEXR-style deep images, we show that the Porter-Duff over function is the operator of a Lie group. In its corresponding Lie algebra, the splitting and mixing functions that OpenEXR deep merging requires have a particularly simple form. Working in the Lie algebra, we present a novel, simple proof of the uniqueness of the mixing function.
The Lie group structure has many more applications, including new, correct resampling algorithms for volumetric images with alpha channels, and a deep image compression technique that outperforms that of OpenEXR.

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References

[1]
George B. Arfken, Hans-Jürgen Weber, and Frank E. Harris. 2013. Mathematical Methods for Physicists: A Comprehensive Guide (7th ed.). Academic Press, New York, NY, USA. xiii + 1205 pages.
[2]
Brian Andrew Barsky. 1981. The Beta-Spline: A Local Representation Based on Shape Parameters and Fundamental Geometric Measures. Ph.D. Dissertation. University of California at Berkeley.
[3]
Jim Blinn. 1994. Image compositing--theory. IEEE Computer Graphics and Applications 14, 5 (Sept. 1994), 83--87.
[4]
Edwin Catmull and Raphael Rom. 1974. A class of local interpolating splines. In Computer Aided Geometric Design, Robert E. Barnhill and Rich F. Reisenfeld (Eds.). Academic Press, New York, NY, 317--326.
[5]
Robert L. Cook, Loren Carpenter, and Edwin Catmull. 1987. The Reyes image rendering architecture. In Proceedings of the 14th Annual Conference on Computer Graphics and Interactive Techniques (SIGGRAPH’87). ACM SIGGRAPH, ACM, New York, NY, 95--102.
[6]
Jonathan Egstad, Mark Davis, and Dylan Lacewell. 2015. Improved deep image compositing using subpixel masks. In Proceedings of the 2015 Symposium on Digital Production (DigiPro’15). ACM SIGGRAPH, ACM, New York, NY, 21--27.
[7]
Andrew Glassner. 2015. Interpreting alpha. Journal of Computer Graphics Techniques (JCGT) 4, 2 (May 2015), 30--44.
[8]
Peter Hillman. 2012. The Theory of OpenEXR Deep Samples. Retrieved from http://www.openexr.com/TheoryDeepPixels.pdf.
[9]
Florian Kainz. 2013. Interpreting OpenEXR Deep Pixels. Retrieved from http://www.openexr.com/InterpretingDeepPixels.pdf.
[10]
S. Lang. 2002. Algebra. Springer New York, New York, NY.
[11]
Tom Lokovic and Eric Veach. 2000. Deep shadow maps. In Proceedings of the 27th Annual Conference on Computer Graphics and Interactive Techniques (SIGGRAPH’00). ACM SIGGRAPH, ACM Press/Addison-Wesley Publishing Co., New York, NY, 385--392.
[12]
Cleve Moler and Charles F. Van Loan. 2003. Nineteen dubious ways to compute the exponential of a matrix, twenty-five years later. SIAM Review 45, 1 (2003), 3--49.
[13]
Thomas Porter and Tom Duff. 1984. Compositing digital images. Computer Graphics 18, 3 (July 1984), 253--259.
[14]
Alvy Ray Smith. 1995. Image Compositing Fundamentals. Technical Report. Microsoft.
[15]
SymPy Development Team. 2015. SymPy Documentation. http://docs.sympy.org/latest/index.html.
[16]
Kristopher Tapp. 2016. Matrix Groups for Undergraduates (2nd ed.). American Mathematical Society, Providence, RI. viii + 239 pages.
[17]
H. F. Trotter. 1959. On the product of semi-groups of operators. Proceedings of the American Mathematical Society 10 (1959), 545--551.

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Published In

cover image ACM Transactions on Graphics
ACM Transactions on Graphics  Volume 36, Issue 3
June 2017
165 pages
ISSN:0730-0301
EISSN:1557-7368
DOI:10.1145/3087678
Issue’s Table of Contents
Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for third-party components of this work must be honored. For all other uses, contact the Owner/Author.

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Association for Computing Machinery

New York, NY, United States

Publication History

Published: 01 June 2017
Accepted: 01 December 2016
Received: 01 September 2016
Published in TOG Volume 36, Issue 3

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Author Tags

  1. Compositing
  2. Lie algebra
  3. Lie group
  4. alpha
  5. atmospheric effects
  6. deep compositing
  7. exponential map

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