Past events

Seeing around corners in natural light using plenoptic observations

Professor James R Leger, University of Minnesota


Several methods have been proposed to solve the problem of “seeing around corners”, where light scatters from a rough surface before it is observed. Although active methods (using, for example illumination with short pulses of laser light) have proven quite effective, they have the distinct disadvantage of being non-covert. In this presentation, we restrict the imaging problem to using only natural light. We examine the efficacy of plenoptic measurements, where the entire four-dimensional radiance function of the scattered light is measured. We quantify the amount of information that is contained in the scattered light and propose several approaches for extracting data from the plenoptic signal. We show that by using a synergistic relationship between the angular and spatial components of the plenoptic function, one can retrieve significant information from the scattered signal, including the three-dimensional location of specific objects and, in some cases, complete image recovery.


Prof. James Leger received his bachelor of science degree in Applied Physics from the California Institute of Technology (1974) and Ph.D. degree in Electrical Engineering from the University of California, San Diego (1980). He has held previous positions at the 3M Company and MIT Lincoln Laboratory. He is currently professor of Electrical Engineering at the University of Minnesota, where he holds the Cymer Professorship for optics research in Electrical Engineering. His research group works in the area of optical design, including coherent laser beam combining and the design of gradient index optics, and information optics, including the design and analysis of imaging systems using light from scattering surfaces. Prof. Leger is currently serving as senior deputy editor of Optics Express and has served on the Board of Directors of the Optical Society of America. Prof. Leger has been awarded the 1998 Joseph Fraunhofer Award/Robert M. Burley Prize by the Optical Society of America, and the 2000 George Taylor Award for Outstanding Research at the University of Minnesota. He has received a number of awards for teaching, resulting in his induction into the academy of distinguished teachers at the University of Minnesota. He is a Fellow of the Optical Society of America, Fellow of the Institute of Electrical and Electronic Engineers (IEEE), and Fellow of the International Society of Optical Engineers (SPIE).