Lens-less wide-field imaging and depth sensing through a turbid scattering layer by round-trip field estimation

Wide-field depth-resolved imaging through scattering media has been a longstanding problem in recent years. In this paper, we proposed a reference-less compact imaging physical model, where the 3D light field data embedded in the volumetric speckle stack through a strong diffuser is explored and analyzed. By utilizing wave-optics and a coherent round-trip field estimation method, the scattering matrix of the diffuser is precisely calibrated as a priori knowledge. After then, the multi-slice targets are placed between the light source and the diffuser, and a set of defocused intensity pattern are recorded for recovering the scattered object field. The real object field is extracted from inverse diffracting of the field employing the conjugation of the calibrated scattering matrix. Wide-field imaging is verified experimentally by recording a resolution chart hidden behind a ground glass. The technique shows great potential in lens-less wave-front sensing and non-reference 3D imaging.