ECE Seminar Speaker Demetri Psaltis École Polytechnique Fédérale de Lausanne Lausanne, Switzerland Faculty Host: Thomas Bifano Light refreshments will be available outside of PHO 339 at 10:45 am. Learning From Examples in Optics Abstract: Psaltis considers optical imaging systems in which the detected output is not directly a reproduction of the object yet it is possible to derive an image of the object by post-detection digital processing. In this talk, he will focus on learning methods to assist in the image formation process. Specifically the optical system is illuminated with various input patterns and the corresponding optical response is recorded. The set of input-output pairs can be thought of as examples with which we can train the system. Psaltis wil consider two cases: Imaging through multimode fibers [1,2] and optical tomography [3]. For multi-mode fibers the learning procedure can be thought of as a calibration step that converts the fiber into a device with imaging capabilities similar to a lens. This can lead to interesting applications in endoscopy. In the case of tomography, we construct a multi-layer neural network that simulates light propagation. The adaptable parameters of the network correspond to the voxel values of the 3D object. Training the network to reproduce the experimentally recorded input-output pairs yields the 3D image of the object. Results suggest that the learning method yields an image quality better than other tomographic reconstruction methods. 1. Focusing and scanning light through a multimode optical fiber using digital phase conjugation, Papadopoulos et. al. , Optics Express, Vol. 20, pp. 10583-10590, April 201 2. Imaging with Multimode fibers, Psaltis D. and Moser C. , Optics and Photonics News, page 26, January 2016. 3.Learning Approach to Optical Tomography, Kamilov et.al., Optica, volume 2, Issue 6, pp. 517-522 (2015) Speaker Bio: Demetri Psaltis is Professor of Optics, Director of the Optics Laboratory and Dean of the Engineering Schools at Ecole Polytechnique Federale de Lausanne (EPFL). He was educated at Carnegie-Mellon University and in 1980, he joined the faculty at the California Institute of Technology, Pasadena. He moved to EPFL in 2006. His current research interests are in imaging, holography, biophotonics, nonlinear optics, and optofluidics. He has authored or co-authored over 400 publications in these areas. Dr. Psaltis is a fellow of the IEEE, the Optical Society of America, the European Optical Society and the Society for Photo-optical Systems Engineering (SPIE). He received the International Commission of Optics Prize, the Humboldt Award, the Leith Medal and the Gabor Prize.