- 27 November 2015: our work was selected as a Research Highlight in Communications of the ACM!
- 29 April 2014: captured videos added in Downloads!
- 03 April 2014: web launched!
We present femto-photography, a novel imaging technique to capture and visualize the propagation of light. With an effective exposure time of 1.85 picoseconds (ps) per frame, we reconstruct movies of ultrafast events at an equivalent resolution of about one half trillion frames per second. Because cameras with this shutter speed do not exist, we re-purpose modern imaging hardware to record an ensemble average of repeatable events that are synchronized to a streak sensor, in which the time of arrival of light from the scene is coded in one of the sensor's spatial dimensions. We introduce reconstruction methods that allow us to visualize the propagation of femtosecond light pulses through macroscopic scenes; at such fast resolution, we must consider the notion of time-unwarping between the camera's and the world's space-time coordinate systems to take into account effects associated with the finite speed of light. We apply our femto-photography technique to visualizations of very different scenes, which allow us to observe the rich dynamics of time-resolved light transport effects, including scattering, specular reflections, diffuse interreflections, diffraction, caustics, and subsurface scattering. Our work has potential applications in artistic, educational, and scientific visualizations; industrial imaging to analyze material properties; and medical imaging to reconstruct subsurface elements. In addition, our time-resolved technique may motivate new forms of computational photography.
- PDF [1.7 MB]
- Main Video [70 MB]
- Captured Videos: Alien [0.3 MB], Bottle [1.77 MB], Candy [0.3 MB], Cube [0.2 MB], Tank [1.71 MB], Tomato [0.1 MB]
- Edited Videos: Bottle [18 MB], Tomato [3 MB]
- Speeds Comparison [7 MB]
- Time Warping [16 MB]
- SIGGRAPH'13 FastForward [4 MB]
- 2015: Relativistic Effects for Time-Resolved Light Transport
- 2014: A Framework for Transient Rendering
We would like to thank the reviewers for their insightful comments, and the entire Camera Culture group for their support. We also thank Greg Gbur for letting us use some of the images shown in Figure 2, Elisa Amoros for the 3D illustrations in Figures 3 and 4, and Paz Hernando and Julio Marco for helping with the video. This work was funded by the Media Lab Consortium Members, the Institute for Soldier Nanotechnologies and U.S. Army Research Office under contract W911NF-07-D-0004, MIT Lincoln Labs and the Army Research Office through the Institute for Soldier Nanotechnologies at MIT, and the Spanish Ministry of Science and Innovation through the Mimesis project, and the EU-funded projects Golem and Verve. Di Wu was supported by the National Basic Research Project (No.2010CB731800) of China and the Key Project of NSFC (No. 61120106003 and 60932007). Belen Masia was additionally funded by an FPU grant from the Spanish Ministry of Education and by an NVIDIA Graduate Fellowship. Ramesh Raskar was supported by an Alfred P. Sloan Research Fellowship and a DARPA Young Faculty Award.