What You Can Learn by Staring at a Blank Wall
       Prafull Sharma1   Miika Aittala1,2  Yoav Y. Schechner3   Antonio Torralba1
           Gregory W. Wornell1   William T. Freeman1   Fredo Durand1
                1      2          3
                  MIT     NVIDIA       Technion - Israel Institute of Technology

                Abstract
  We present a passive non-line-of-sight method that infers
the number of people or activity of a person from the obser-
vation of a blank wall in an unknown r ...