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Alexei A. Efros
Assistant Professor, RI/CS

Email address: efros@cs.cmu.edu

Mailing address:
Carnegie Mellon University
Robotics Institute
5000 Forbes Avenue
Pittsburgh, PA 15213

For more information, see my personal homepage.

Jump to: Research interests | Keywords | Labs & groups | Projects | Publications

My research is in the area of computer vision and computer graphics, especially at the intersection of the two. I am particularly interested in using data-driven techniques to tackle problems which are very hard to model parametrically but where large quantities of data are readily available. The ultimate goal is to use the ever-growing amount of stored visual information (digital photo albums, webcams, movies, etc.) to learn, understand, and resynthesize the visual world around us.

In very broad strokes, here are the main current themes of my research:

• Qualitative 3D Reasoning for Image Interpretation: The ability to see and understand the three-dimensional world behind a two-dimensional image goes to the very heart of the computer vision problem. The overall objective of this research effort is, given a single image, to automatically produce a coherent interpretation of the depicted scene. On one level, such interpretation should include opportunistically recognizing known objects (e.g. people, houses, cars, trees) and known materials (e.g. grass, sand, rock, foliage) as well as their rough positions and orientations within the scene. But more than that, the goal is to capture the overall qualitative sense of the scene.

• "Brute-forcing" Vision: What could you do with a billion images? Taking inspiration from Google -- the A.I. for the post-modern world -- we want to utilize the huge amount of existing visual data to "look-up" similar images as a cue to interpreting a previously unseen photograph. That is, we would like to sample from the entire space of scenes as a way of exhaustively modeling our visual world? If this works, it might allow us to "brute force" many currently unsolvable vision and graphics problems!

• Understanding (and Faking) Visual Realism: Why is it that most of computer-generated imagery doesn't look very realistic? What is it that the Renaissance artists knew that we don't? Which bits of the visual experience is it important to "get right", and which could be safely faked without anyone noticing? The ultimate goal is to make synthesized images appear as real and convincing as regular photographs.

computer graphics, computer vision, image processing, machine learning, and object recognition

• Computer Graphics Lab - Modeling, animation, and rendering of 3-D scenes

• Geometrically Coherent Image Interpretation - Understanding a 3D scene from a single image

• Closing the Loop on Scene Interpretation
  D. Hoiem, A.A. Efros, and M. Hebert
  Proc. Computer Vision and Pattern Recognition (CVPR), June, 2008.
  Download: pdf [5469 KB] copyrighted

• Recognition by Association via Learning Per-exemplar Distances
  T. Malisiewicz and A.A. Efros
  Proc. Computer Vision and Pattern Recognition (CVPR), June, 2008. [Abstract]
  Download: pdf [7859 KB] copyrighted

• Image-based Shaving
  M.H. Nguyen, J. Lalonde, A.A. Efros, and F. De la Torre Frade
  Computer Graphics Forum Journal (Eurographics), Vol. 27, No. 2, April, 2008, pp. 627 - 635. [Abstract]
  Download: pdf [5705 KB] copyrighted

• Recovering Occlusion Boundaries from a Single Image
  D. Hoiem, A. Stein, A.A. Efros, and M. Hebert
  International Conference on Computer Vision (ICCV), October, 2007. [Abstract]
  Download: pdf [2337 KB] copyrighted

• Recovering Surface Layout from an Image
  D. Hoiem, A.A. Efros, and M. Hebert
  International Journal of Computer Vision, Vol. 75, No. 1, October, 2007. [Abstract]
  Download: pdf [1887 KB] copyrighted

• Using Color Compatibility for Assessing Image Realism
  J. Lalonde and A.A. Efros
  International Conference on Computer Vision (ICCV), October, 2007. [Abstract]
  Download: pdf [10946 KB] copyrighted

• Improving Spatial Support for Objects via Multiple Segmentations
  T. Malisiewicz and A.A. Efros
  British Machine Vision Conference (BMVC), September, 2007. [Abstract]
  Download: pdf [2423 KB] copyrighted

• Photo Clip Art
  J. Lalonde, D. Hoiem, A.A. Efros, C. Rother, J. Winn, and A. Criminisi
  ACM Transactions on Graphics (SIGGRAPH 2007), Vol. 26, No. 3, August, 2007. [Abstract]
  Download: pdf [15963 KB] copyrighted

• Scene Completion Using Millions of Photographs
  J.H. Hays and A.A. Efros
  ACM Transactions on Graphics (SIGGRAPH 2007), Vol. 26, No. 3, August, 2007. [Abstract]
  Download: pdf [11635 KB] copyrighted

• Opportunistic use of vision to push back the path-planning horizon
  B. Nabbe, D. Hoiem, A.A. Efros, and M. Hebert
  Proceedings: IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS '06), October, 2006, pp. 2388 - 2393. [Abstract]
  Download: pdf [709 KB] copyrighted