Nuit Blanche: MIT team presents an interesting concept of lensless camera in arxiv.org paper "Lensless Imaging with Compressive Ultrafast Sensing" by Guy Satat, Matthew Tancik, and Ramesh Raskar. Actually, there is a projection optics in the system, but only on the illuminator side:
"Here we present a method for lensless imaging based on compressive ultrafast sensing. Each sensor acquisition is encoded with a different illumination pattern and produces a time series where time is a function of the photon’s origin in the scene. Currently available hardware with picosecond time resolution enables time tagging photons as they arrive to an omnidirectional sensor. This allows lensless imaging with significantly fewer patterns compared to regular single pixel imaging. To that end, we develop a framework for designing lensless imaging systems that use ultrafast detectors."
MIT Media Lab video explains how it works: