Alexei (Alyosha) Efros

Adjunct Associate Professor
The Robotics Institute
and Computer Science Department
School of Computer Science
Carnegie Mellon University
Pittsburgh, PA 15213, USA

Office: 225 Smith Hall
Phone: +1 (412) 268-1234
Email: efr...@cs.cmu.edu

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After a wonderful decade at CMU, I have moved the the EECS Department at UC Berkeley in Fall 2013. Please visit my new web page.

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. Since 2004, I am faculty at CMU with a joint appointment in the Robotics Institute and CS Department (and a courtesy appointment in Machine Learning Department). I am a member of the CMU Computer Vision Group and the CMU Graphics Lab, and also have close collaboration with the WILLOW Lab at INRIA/ENS in Paris.

Here is a slightly more official bio.

Research

Antonio Torralba and I are guest-editing an IJCV special issue on Big Visual Data. Submission Deadline: extended to May 31.

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 visual data, now called "Big Data", are readily available (see my recent talk on "What Makes Big Visual Data Hard?"). 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 all visual elements, i.e. a giant multi-graph. Once constructed, the visual memex can be used 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, Russell'09, Malisiewicz'11, Shrivastava'11.

• 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.

Postdocs

• Olivier Duchenne (co-advised with Martial Hebert)
• Yong Jae Lee (co-advised with Martial Hebert)

Graduate Students

• Carl Doersch (MLD, PhD)
• Paul Sastrasinh (CSD, PhD, co-advised with Kayvon Fatahalian)
• Abhinav Shrivastava (Robotics, PhD, co-advised with Abhinav Gupta and Martial Hebert)
• Tinghui Zhou (Robotics, MS)
• Jun-Yan Zhu (CSD, PhD)

Former PhD Students

• Dr. Santosh Kumar Divvala (Robotics, PhD 2012, now postdoc at University of Washington), co-advised with Martial Hebert
  • PhD Thesis -- Context and Subcategories for Sliding Window Object Recognition
• Dr. Tomasz Malisiewicz (Robotics, PhD 2011, now postdoc at MIT)
  • PhD Thesis -- Exemplar-based Representations for Object Detection, Association and Beyond
• Dr. Jean-François Lalonde (Robotics, PhD 2011, now postdoc at Disney Research), co-advised with Srinivas Narasimhan
  • PhD Thesis -- Understanding and Recreating Visual Appearance Under Natural Illumination
    Recipient of CMU School of Computer Science Distinguished Dissertation Award
• Dr. James Hays (CSD, PhD 2009, now assistant professor at Brown)
  • PhD Thesis -- Large Scale Scene Matching for Graphics and Vision
• Dr. Derek Hoiem (Robotics, PhD 2007, now assistant professor at UIUC), co-advised with Martial Hebert
  • PhD Thesis -- Seeing the World Behind the Image: Spatial Layout for 3D Scene Understanding
    Recipient of CMU School of Computer Science Distinguished Dissertation Award
    Recipient of ACM Doctoral Dissertation Honorable Mention

Former Postdocs

• Ali Farhadi (2011-2012, now assistant professor at University of Washington), co-advised with Martial Hebert
• Abhinav Gupta (2009-2011, now assistant research professor at CMU), co-advised with Martial Hebert

Teaching

• Fall 2012: 15-463 (15-663, 15-862): Computational Photography
• Spring 2012: 16-824: Learning-based Methods in Vision
• Fall 2011: 15-463 (15-862): Computational Photography
• Spring 2011: 16-899A: Pixels to Percepts: 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

Selected Projects

List of all my publications is also available on Google Scholar.