We have built a camera that can look around corners and beyond the line of sight. The camera uses light that travels from the object to the camera indirectly, by reflecting off walls or other obstacles, to reconstruct a 3D shape.
CORNAR: Looking Around Corners using Trillion FPS Imaging
1. Raskar, Camera Culture, MIT Media Lab
Computational Light Transport:
CORNAR: Looking Around Corners
Camera Culture using
Trillion FPS Imaging
Ramesh Raskar
Ramesh Raskar
MIT Media Lab http://raskar.info/cornar
8. Co-designing Optical and Digital Processing
Computational
Optics
Light Transport
Photon Hacking
Displays
Sensors Computational
Illumination Photography
Signal Processing
Computer Vision
Machine Learning
Bit Hacking
10. CORNAR: Femto-Photography
FemtoFlash
Trillion FPS camera
With M Bawendi,
MIT Chemistry
Serious Sync
Computational Optics
•2012: 3D around a corner (NatureComm, Velten, et. al.)
•2011: Material Sensing (Siggraph Asia, Naik, Zhao, Velten, Raskar, Bala)
•2011: DARPA Young Faculty Award
•2011: Motion Sensing (CVPR, Pandharkar, Velten, Bardagjy, Bawendi, Raskar)
•2009: Hidden barcode (Kirmani, Hutchinson, Davis, Raskar, ICCV’2009)
•2008: Indirect depth (Hirsch, Raskar)
•2008: Transient Light Transport (Raskar, Davis, March 2008)
11. Inverting Light Transport
Multiple Scattering Direct/Global
[Seitz , Kutulakos, Matsushita 2005] [Nayar, Raskar et al 2006]
[Atcheson et al 2008]
[Kutulakos, Steger 2005]
Dual Photography LIDAR
[Sen et al 2005]
18. Why Pico-second Resolution?
ToF Diff = 0.15 mm
s2
1cm
s1
Occluder
3rd bounce
Streak-
camera
C p1
p2
1st bounce
Curse of Pythagoras
19. z
S x
L
R
s
Occluder
Streak-
camera
3rd bounce
Streak Photo
C Laser
B beam
Echoes of Light
20. Trillion FPS
ToF Streak Tube = Inverse of CRT
Very accurate sync
1D camera: Single scan line stretched vertically in time
~2 ps resolution, 480 lines ~= 1 ns
But for small samples in biochemistry
22. Time Image of a single point
Time, ~2ns each row
Space, 640 pixels
Third Bounce (First bounce not shown)
25. 3D shape result from
synthetic data
Forward Reconstruction Invertibility Analysis
Wavefront Non-linear Scene Priors Resolution and
Propagation Inversion dimensions
26. Steady State 4D
[Kajiya, 1986] [Seitz.., 2005]
Impulse Response, 5D
[Raskar and Davis, 2007]
27. Time Resolved Multi-path Imaging
Scene with
hidden elements Ultra fast illumination and camera
5D Raw
Capture Time
profiles
Signal
Proc.
Photo, geometry,
reflectance Novel light transport
beyond models and inference
line of sight algorithms →
t
3D Time images
53. http://raskar.info
Femto-Photography
Looking Around the Corner
BRDF Detection
Trillion FPS
Movies
Space-time Transforms
Editor's Notes
The idea is to use the multiple bounces of light i.e. echoes of light.
My work involves creative new ways to play with light by co-designing optical and digital processing. My work lies at the INTERSECTION of processing of photons and processing of bits. At MERL, I transformed the field of computational photography, with key papers and impact on products At Media Lab, I invented a new field ‘computational light transport’
My idea is to use the multiple bounces of light i.e. echoes of light.
This new form of imaging is possible by fusion of dissimilar .. A specialized camera previously used only in biochemistry labs and a new computational method that analyzes multiple bounces of light. I started the project just before I joined MIT in summer 2008. The hardware we use is borrowed and is in the lab of Prof Bawendi, MIT Chemistry, who is now a collaborator
Here is the pipeline of how we see around corners. We have developed all the mathematical theory and now pushing into the physical experiments.
The original formulation was in the Raskar, Davis paper in 2007.
Here is a road map for this ambitious research project based on time-resolved imaging .. Non line of sight Looking around corner (LaC) is just one example .. Such Time resolved imaging requires one to develop a completely new set of tool for understanding our world. This is a project I started just before coming to MIT in 2008 via an NSF proposal.
The reconstruction back in Fall 2010 was very low, about 80x80 pixels. So these are just baby steps. Top: synthetic results based on physically realistic simulations Bottom: real world results
Top: synthetic results based on physically realistic simulations Bottom: real world results
New results
We can also infer reflectance and albedo Started working on a paper after a casual conversation between Raskar and Kavita Bala