Caltech Logo
Biophotonics Lab
Home  /  Research  /  Non-line-of-sight Imaging

Research: Non-line-of-sight imaging via wavefront shaping

Non-line-of-sight imaging based on wavefront shaping

Conventional non-line-of sight imaging relies on the time difference of the arriving photons to reconstruct the shape of the target that is hidden from the direct line-of-sight. Here, we are investigating whether we can correct the random wavefront modulation due to the scattering of the wall, and focus onto the hidden target. In an actual non-line-of-sight setting, prior manipulation on the target is infeasible. Thus, we need to use the target itself as the guidestar. We invented a new method that controls the light such that we can synthesize a much smaller focus when comparing with the target, which can be raster scanned to form an image later [1]. The figure below illustrates the process of using small apertures to generate a large aperture.

nlos-setup
Fig. 1: Concept of our system. The optimization steps are illustrated in a and b. Apply the phase masks optimized in a and b, we can get a much smaller focus.

Reference:

  1. Cao, R., de Goumoens, F., Blochet, B., Xu, J. and Yang, C. High-resolution non-line-of-sight imaging employing active focusing. Nature Photonics 16, 462–468 (2022).