Alyosha Efros homepage

Alexei (Alyosha) Efros

Finmeccanica Associate Professor
The Robotics Institute
and Computer Science Department
School of Computer Science
Carnegie Mellon University
Pittsburgh, PA 15213, USA
Office: 4207 Newell-Simon Hall
Phone: +1 (412) 268-1234
Email: efr...@cs.cmu.edu

I am originally from St. Petersburg, Russia, but, due to some mixup at the travel agency, I now live in Pittsburgh, USA. I got my PhD from UC Berkeley in 2003 under the supervision of Jitendra Malik. I then spent a year as a fine fellow in lovely Oxford, working with Andrew Zisserman and the Visual Geometry Group. I came to CMU in autumn of 2004 with a joint appointment in the Robotics Institute (my official RI page) and CS Department. I am a member of the CMU Graphics Lab and also have close collaboration with the VMR Lab at CMU and WILLOW Lab at ENS-Ulm in Paris.

Here is a slightly more official bio.

Research

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 group's research:

Qualitative Reasoning for Image Understanding: 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 be able to qualitativly capture scene properties such as geometric layout, occlusion relationships, camera viewpoint, scale, illumination, geographic properties, etc. But more than that, the goal is to capture the overall qualitative sense of the scene. For an overview, see my recent keynote lecture at BMVC'09.
Building the "Visual Memex": What could you do with a billion images? Can this vast heap of data be organized without loosing its representation power? Taking inspiration from Vannevar Bush's memex, our aim is to utilize the huge amount of existing visual data to discover links and connections between visual elements. The goal is to "explain" novel visual signal not in terms of hard categories ("car", "chair", "city"), but rather in terms of what has been seen before. Rather than asking "What is this?", we'd like to ask "What is this like?". For an overview, see my recent presentation and representative publications: Malisiewicz'08, Malisiewicz'09, Hays'08.
Understanding (and Faking) Visual Realism: Why is it that most 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. Representative publications: Lalonde'07, Lalonde'07b, Hays'07, Lalonde'09.

Teaching

Spring 2011: 15-8??: Human Visual Perception for Vision and Graphics
Fall 2010: 15-463 (15-862): Computational Photography
Spring 2010: 15-463 (15-862): Computational Photography
Fall 2009: on leave at ENS-Ulm, Paris (on Guggenheim fellowship)
Spring 2009: 16-721: Learning-based Methods in Vision
Fall 2008: 15-463 (15-862): Computational Photography
Fall 2008: 15-996: CSD Immigration Course
Spring 2008: no teaching
Fall 2007: 15-463 (15-862): Computational Photography
Fall 2007: 15-462: Computer Graphics
Spring 2007: 16-721: Learning-based Methods in Vision
Fall 2006: 15-463 (15-862): Computational Photography
Spring 2006: 16-721: Advanced Machine Perception
Fall 2005: 15-463 (15-862): Computational Photography
Fall 2004: 15-463 Rendering and Image Processing

Postdoc

Dr. Abhinav Gupta (co-advised with Martial Hebert)

Graduate Students

Santosh Kumar Divvala (Robotics, PhD, co-advised with Martial Hebert)
Jean-François Lalonde (Robotics, PhD, co-advised with Srinivas Narasimhan)
Tomasz Malisiewicz (Robotics, PhD)

Former Students

Dr. James Hays (CSD, PhD 2009, assistant professor at Brown)
- PhD Thesis -- Large Scale Scene Matching for Graphics and Vision
Dr. Derek Hoiem (Robotics, PhD 2007, assistant professor at UIUC), co-advised with Martial Hebert
- PhD Thesis -- Seeing the World Behind the Image: Spatial Layout for 3D Scene Understanding
  Winner of: CMU School of Computer Science Distinguished Dissertation Award and ACM Doctoral Dissertation Honorable Mention

Selected Projects

List of all my publications is available as BibTeX file or from Google Scholar.

	Blocks World Revisited: Image Understanding using Qualitative Geometry and Mechanics Abhinav Gupta, Alexei A. Efros, Martial Hebert in ECCV 2010
	Detecting Ground Shadows in Outdoor Consumer Photographs Jean-François Lalonde, Alexei A. Efros, Srinivasa G. Narasimhan in ECCV 2010 Source code available
	Beyond Categories: The Visual Memex Model for Reasoning About Object Relationships Tomasz Malisiewicz, Alexei A. Efros in NIPS 2009.
	Segmenting Scenes by Matching Image Composites Bryan Russell, Alexei A. Efros, Josef Sivic, Bill Freeman, Andrew Zisserman in NIPS 2009
	Webcam Clip Art: Appearance and Illuminant Transfer from Time-lapse Sequences Jean-François Lalonde, Alexei A. Efros, Srinivasa G. Narasimhan in SIGGRAPH Asia 2009 Source code available
	Image Composition for Object Pop-out Hongwen (Henry) Kang, Alexei A. Efros, Takeo Kanade, Martial Hebert Workshop on 3D Representation for Recognition (3dRR-09) (at ICCV 2009)
	Estimating Natural Illumination from a Single Outdoor Image Jean-François Lalonde, Alexei A. Efros, Srinivasa G. Narasimhan in ICCV 2009 Source code available
	Image Sequence Geolocation with Human Travel Priors Evangelos Kalogerakis, Olga Vesselova, James Hays, Alexei A. Efros, Aaron Hertzmann in ICCV 2009
	An Empirical Study of Context in Object Detection Santosh Kumar Divvala, Derek Hoiem, James Hays, Alexei A. Efros, Martial Hebert in CVPR 2009
	What Does the Sky Tell Us About the Camera? Jean-François Lalonde, Srinivasa G. Narasimhan, Alexei A. Efros. in ECCV 2008 (see also expanded journal version, IJCV 2009) Source code available
	Can Similar Scenes help Surface Layout Estimation? Santosh Kumar Divvala, vAlexei A. Efros, Martial Hebert in IEEE Workshop on Internet Vision, at CVPR'08
	Recognition by Association via Learning Per-exemplar Distances Tomasz Malisiewicz, Alexei A. Efros in CVPR 2008. Source code available
	im2gps: estimating geographic information from a single image James Hays, Alexei A. Efros in CVPR 2008. Flickr download code available See interview with Hays on Pittsburgh TV station. And another one.
	Closing the Loop on Scene Interpretation Derek Hoiem, Alexei A. Efros, Martial Hebert in CVPR 2008. See 3D reconstruction compared to Photo Pop-up and Make3D
	Image-based Shaving Minh Hoai Nguyen, Jean-François Lalonde, Alexei A. Efros, Fernando de la Torre in Eurographics 2008.
	Recovering Occlusion Boundaries from a Single Image Derek Hoiem, Andrew Stein, Alexei A. Efros, Martial Hebert in ICCV 2007. Source code available
	Using Color Compatibility for Assessing Image Realism Jean-François Lalonde, Alexei A. Efros in ICCV 2007.
	Improving Spatial Support for Objects via Multiple Segmentations Tomasz Malisiewicz, Alexei A. Efros in BMVC 2007.
	Scene Completion using Millions of Photographs James Hays, Alexei A. Efros in SIGGRAPH 2007. Flickr download code available See article on BBC News See also Communications of the ACM article with forward by Marc Levoy
	Photo Clip Art Jean-François Lalonde, Derek Hoiem, Alexei Efros, Carsten Rother, John Winn, Antonio Criminisi in SIGGRAPH 2007. Try the Live Java Demo
	Putting Objects in Perspective Derek Hoiem, Alexei A. Efros, Martial Hebert In CVPR 2006. Source code available CVPR Best Paper Award (see also expanded journal version, IJCV 2008)
	Using Multiple Segmentations to Discover Objects and their Extent in Image Collections Bryan Russell, Alexei A. Efros, Josef Sivic, Bill Freeman, Andrew Zisserman in CVPR 2006 Source code available
	Discovering Texture Regularity as a Higher-Order Correspondence Problem James Hays, Marius Leordeanu, Alexei A. Efros, Yanxi Liu in ECCV 2006 Source code available upon request.
	Geometric Context from a Single Image Derek Hoiem, Alexei A. Efros, Martial Hebert In ICCV 2005 (see also expanded journal version, IJCV 2007) Executable available (for non-commerical use only)
	Discovering Objects and thier Location in Images Josef Sivic, Bryan Russell, Alexei A. Efros, Andrew Zisserman, Bill Freeman In ICCV 2005
	Automatic Photo Pop-up Derek Hoiem, Alexei A. Efros, Martial Hebert In SIGGRAPH 2005 See article in The Economist
	A Data-Driven Approach to Quantifying Natural Human Motion Liu Ren, Alton Patrick, Alexei A. Efros, Jessica Hodgins. James Rehg. In SIGGRAPH 2005
	Seeing Through Water Alexei A. Efros, Volkan Isler, Jianbo Shi, Mirko Visontai In NIPS 17, 2004 Data available as frames or video
	Recovering Human Body Configurations: Combining Segmentation and Recognition Greg Mori, Xiaofeng Ren, Alexei A. Efros, Jitendra Malik In CVPR 2004
	Recognizing Action at a Distance Alexei A. Efros, Alexander Berg, Greg Mori, Jitendra Malik In ICCV 2003
	Image Quilting for Texture Synthesis and Transfer Alexei A. Efros, Bill Freeman In SIGGRAPH 2001 Source code available
	Texture Synthesis by Non-parametric Sampling Alexei A. Efros, Thomas Leung In ICCV 1999