Incoherent lensless imaging via coherency back-propagation.

The two-point complex coherence function constitutes a complete representation for scalar quasi-monochromatic optical fields. Exploiting dynamically reconfigurable slits implemented with a digital micromirror device, we report on measurements of the complex two-point coherence function for partially coherent light scattering from a "scene" composing one or two objects at different transverse and axial positions with respect to the source. Although the intensity shows no discernible shadows in the absence of a lens, numerically back-propagating the measured complex coherence function allows estimating the objects' sizes and locations and, thus, the reconstruction of the scene subject to the effects of occlusion and shadowing.