Fast non-line-of-sight imaging with high-resolution and wide field of view using synthetic wavelength holography

Florian Willomitzer,Marc P Christensen,Prasanna V Rangarajan,Fengqiang Li,Muralidhar M Balaji,Oliver Cossairt

doi:10.1038/s41467-021-26776-w

Florian Willomitzer, Marc P Christensen + Show 4 more

Open Access

https://doi.org/10.1038/s41467-021-26776-w

Copy DOI

Abstract

The presence of a scattering medium in the imaging path between an object and an observer is known to severely limit the visual acuity of the imaging system. We present an approach to circumvent the deleterious effects of scattering, by exploiting spectral correlations in scattered wavefronts. Our Synthetic Wavelength Holography (SWH) method is able to recover a holographic representation of hidden targets with sub-mm resolution over a nearly hemispheric angular field of view. The complete object field is recorded within 46 ms, by monitoring the scattered light return in a probe area smaller than 6 cm × 6 cm. This unique combination of attributes opens up a plethora of new Non-Line-of-Sight imaging applications ranging from medical imaging and forensics, to early-warning navigation systems and reconnaissance. Adapting the findings of this work to other wave phenomena will help unlock a wider gamut of applications beyond those envisioned in this paper.

Highlights

The presence of a scattering medium in the imaging path between an object and an observer is known to severely limit the visual acuity of the imaging system
● High temporal resolution: ToF-based approaches require point-wise raster-scanning, while we demonstrate the ability to recover holograms of the obscured object within two shots using conventional focal plane array (FPA) technology
The present work combines the expressive power of holography with spectral correlations in scattered light to address the challenging problem of Non Line-of-Sight Imaging (NLoS) imaging

Summary

Introduction

The presence of a scattering medium in the imaging path between an object and an observer is known to severely limit the visual acuity of the imaging system. The complete object field is recorded within 46 ms, by monitoring the scattered light return in a probe area smaller than 6 cm × 6 cm This unique combination of attributes opens up a plethora of new Non-Line-of-Sight imaging applications ranging from medical imaging and forensics, to early-warning navigation systems and reconnaissance. Many attempts[1,2,3,4,5,6,7,8,9,10,11,12,13] have been made to non-invasively recover images of objects obscured from direct view These techniques are collectively referred to as Non Line-of-Sight Imaging (NLoS) in our work. The ME does limit the FoV, and the maximal possible size of the measured object which cannot exceed the respective working volume

Methods

Results

Conclusion