Dynamic noninvasive imaging through turbid media under low signal-noise-ratio

Abstract

In turbid media, scattering of light scrambles information of the incident beam and represents an obstacle to optical imaging. Noninvasive imaging through opaque layers is especially challenging for reliable image reconstruction and dynamic objects. We here propose a solution to these problems: rather than using the full point-spread function or its Fourier transform (optical transfer function, OTF), the wave distortions in scattering layers can be characterized and diffraction-limited imaging performed using only the phase of OTF. Based on this understanding, we develop a method that exploits the redundant information from multiple measurements, which reliably yields OTF phases within several iterations. This method enables noninvasive imaging through turbid media with low signal-to-noise ratios in the measurements, which is not possible with previous methods. We then demonstrate noninvasive video imaging of a moving object hidden between scattering layers at 25-200 Hz. This imaging approach may inspire many other applications in scattering materials.