Computational Imaging Photon by Photon

Arizona Optical Sciences Colloquium: Andreas Velten, "Computational Imaging Photon by Photon"

Abstract

Our cameras usually measure light as an analog flux that varies as a function of space and time. This approximation ignores the quantum nature of light which is actually made of discrete photons each of which is collected at a sensor pixel at an instant in time. Single photon cameras have pixels that can detect photons and the timing of their arrival resulting in cameras with unprecedented capabilities. Concepts like motion blur, exposure time, and dynamic range that are essential to conventional cameras do not really apply to single photon sensors. In this presentation I will cover computational imaging capabilities enabled by single photon cameras and their applications.

The extreme time resolution of single photon cameras enables time of flight measurements we use for Non-Line-of-Sight (NLOS) Imaging. NLOS systems reconstruct images of scene using indirect light from reflections off a diffuse relay surface. After illuminating the relay surface with short pulses, the returning light is detected with high time resolution single photon cameras. We thereby capture video of the light propagation in the visible scene and reconstruct images of hidden parts of the scene.

Over the past decade NLOS imaging has seen rapid progress and we can now capture and reconstruct hidden scenes in real time and with high image quality. In this presentation I will give an overview over the imaging using single photon avalanche diodes, reconstruction methods, and applications driving NLOS imaging and provide an outlook for future development.

Bio

Andreas Velten is Associate Professor at the Department of Biostatistics and Medical Informatics and the Department of Electrical and Computer Engineering at the University of Wisconsin-Madison and directs the Computational Optics Group. He obtained his PhD with Prof. Jean-Claude Diels in Physics at the University of New Mexico in Albuquerque and was a postdoctoral associate of the Camera Culture Group at the MIT Media Lab. He has included in the MIT TR35 list of the world's top innovators under the age of 35 and is a senior member of NAI, OSA, and SPIE as well as a member of Sigma Xi. He is co-Founder of Onlume, a company that develops surgical imaging systems, and Ubicept, a company developing single photon imaging solutions.