SH-ToF: Micro resolution time-of-flight imaging with superheterodyne interferometry

Li, Fengqiang; Willomitzer, Florian; Rangarajan, Prasanna; Gupta, Mohit; Velten, Andreas; Cossairt, Oliver

doi:10.1109/iccphot.2018.8368473

Cited by 16 publications

(16 citation statements)

References 24 publications

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“…Synthetic wavelength holography. Our SWH approach draws inspiration from multi-wavelength interferometry on rough surfaces [40][41][42][43][44][45][46] : We exploit spectral correlations in scattered light at optical wavelengths λ 1 , λ 2 to assemble a hologram of the obscured objects at the SWL Λ ¼ λ 1 λ 2 jλ 1 À λ 2 j . The approach provides a combination of capabilities that is unmatched by competing NLoS approaches:…”

Section: Resultsmentioning

confidence: 99%

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

Willomitzer

Rangarajan

et al. 2021

Nat Commun

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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.

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Section: Resultsmentioning

confidence: 99%

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

Willomitzer

Rangarajan

et al. 2021

Nat Commun

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“…For example, as we demonstrate in Section 7, our paper makes it possible to integrate very general probing functionalities with optical coherence tomography systems [Huang et al 1991], commonly-used for tissue imaging and retinal imaging application. Another application includes interferometric shape-measurement devices [Li et al 2018[Li et al , 2017Maeda et al 2018], which are common in industry and fabrication where it is necessary to obtain measurements at micrometer scales: As these devices already use interferometric measurements, it is relatively straightforward to extend them to additionally incorporate probing using our technique. By contrast, it is unclear how one could implement probing in these systems using a projector-camera technique.…”

Section: Why Use Interferometry With Coded Mutual Intensity?mentioning

confidence: 99%

“…More recently, an increased number of interferometric techiques have been introduced in the computer vision and graphics literature. For example, interferometric techniques have been used for refocusing [Cossairt et al 2014], and high-resolution depth sensing [Li et al 2018[Li et al , 2017Maeda et al 2018]. Most closely related to our paper is the work of Gkioulekas et al [2015], who use interferometry to perform transient imaging, optionally combined with different types of probing.…”

Section: Related Workmentioning

confidence: 99%

Interferometric transmission probing with coded mutual intensity

2020

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We introduce a new interferometric imaging methodology that we term interferometry with coded mutual intensity, which allows selectively imaging photon paths based on attributes such as their length and endpoints. At the core of our methodology is a new technical result that shows that manipulating the spatial coherence properties of the light source used in an interferometric system is equivalent, through a Fourier transform, to implementing light path probing patterns. These patterns can be applied to either the coherent transmission matrix, or the incoherent light transport matrix describing the propagation of light in a scene. We test our theory by building a prototype inspired by the Michelson interferometer, extended to allow for programmable phase and amplitude modulation of the illumination injected in the interferometer. We use our prototype to perform experiments such as visualizing complex fields, capturing direct and global transport components, acquiring light transport matrices, and performing anisotropic descattering, both in steady-state imaging and, by combining our technique with optical coherence tomography, in transient imaging. CCS Concepts: • Computing methodologies → Computational photography.

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“…Interferometry gives micrometer resolution [29] in a carefully controlled environment. Li et al [30] recover micro-resolution ToF using the superheterodyne technique. Maeda et al [31] leverages the heterodyne technique to the polarization imaging to obtain the accurate depth.…”

Section: Related Workmentioning

confidence: 99%

Phase disambiguation using spatio-temporally modulated illumination in depth sensing

Kushida

Tanaka

Aoto

et al. 2020

IPSJ T Comput Vis Appl

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Phase ambiguity is a major problem in the depth measurement in either time-of-flight or phase shifting. Resolving the ambiguity using a low frequency pattern sacrifices the depth resolution, and using multiple frequencies requires a number of observations. In this paper, we propose a phase disambiguation method that combines temporal and spatial modulation so that the high depth resolution is preserved while the number of observation is kept. A key observation is that the phase ambiguities of temporal and spatial domains appear differently with respect to the depth. Using this difference, the phase can disambiguate for a wider range of interest. We develop a prototype to show the effectiveness of our method through real-world experiments.

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SH-ToF: Micro resolution time-of-flight imaging with superheterodyne interferometry

Cited by 16 publications

References 24 publications

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

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

Interferometric transmission probing with coded mutual intensity

Phase disambiguation using spatio-temporally modulated illumination in depth sensing

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