&lt;title&gt;Navigation through fog using stereoscopic active imaging&lt;/title&gt;

Watkins, Wendell R.; Tofsted, David H.; CuQlock-Knopp, V. Grayson; Jordan, Jay B.; Merritt, John O.

doi:10.1117/12.389357

Cited by 9 publications

(4 citation statements)

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“…Clearly, rapid techniques providing wide-field demodulation imaging are greatly desirable as they would not only permit real-time applications like navigation, but would also open up possibilities for for 3D ranging and imaging, vibrometry, optical communications, and specialised scientific instrumentation. Such imaging at high frequencies would be a leap forward for imaging through turbid media, a field of interest that has bearing on vision through opaque scattering walls [10][11][12][13][14][15], medical diagnosis [16][17][18][19], food quality analysis [20], transport safety [5,21,22], underwater vision [23] and imaging through fog [3]. Progressing from single-pixel lock-in detection to simultaneous demodulation over millions of pixels to achieve snapshot image demodulation would bring to the realm observation of spatially distributed and fast physical effects that remain otherwise undetectable.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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An all-optical technique enables instantaneous single-shot demodulation of images at high frequency

et al. 2020

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High-frequency demodulation of wide area optical signals in a snapshot manner is a technological challenge that, if solved, could open tremendous perspectives in 3D imaging, free-space communications, or even ballistic photon imaging in highly scattering media. We present here a novel snapshot quadrature demodulation imaging technique, capable of estimating the amplitude and phase of light modulated from a single frame acquisition, without synchronization of emitter and receiver, and with the added capability of continuous frequency tuning. This all-optical setup relies on an electro-optic crystal that acts as a fast sinusoidal optical transmission gate and which, when inserted in an optimized optical architecture, allows for four quadrature image channels to be recorded simultaneously with any conventional camera. We report the design, experimental validation and examples of potential applications of such a wide-field quadrature demodulating system that allowed snapshot demodulation of images with good spatial resolution and continuous frequency selectivity, at modulation frequencies up to 500 kHz; no fundamental impediment in modulating/demodulating in the range 100-1000 MHz range is foreseen. * julien.fade@univ-rennes1.fr arXiv:1909.05366v1 [physics.ins-det]

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An all-optical technique enables instantaneous single-shot demodulation of images at high frequency

et al. 2020

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“…Imaging through and within turbid media is an area of interest that has tremendous application in medical diagnostics [1], underwater vision [2], imaging through colloids [3] and transportation and navigational aids [4,5]. Light traveling through a complex medium with randomly distributed positions and refractive indices undergoes absorption and random scattering and loses the spatial and temporal information of its source.…”

Section: Introductionmentioning

confidence: 99%

Theoretical optimal modulation frequencies for scattering parameter estimation and ballistic photon filtering in diffusing media

Panigrahi¹,

Fade²,

Ramachandran³

et al. 2016

Opt. Express

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The efficiency of using intensity modulated light for the estimation of scattering properties of a turbid medium and for ballistic photon discrimination is theoretically quantified in this article. Using the diffusion model for modulated photon transport and considering a noisy quadrature demodulation scheme, the minimum-variance bounds on estimation of parameters of interest are analytically derived and analyzed. The existence of a variance-minimizing optimal modulation frequency is shown and its evolution with the properties of the intervening medium is derived and studied. Furthermore, a metric is defined to quantify the efficiency of ballistic photon filtering which may be sought when imaging through turbid media. The analytical derivation of this metric shows that the minimum modulation frequency required to attain significant ballistic discrimination depends only on the reduced scattering coefficient of the medium in a linear fashion for a highly scattering medium.

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“…Imaging of objects and light sources hidden behind a turbid medium has wide applications in areas pertaining to medical diagnostics [1,2], remote sensing [3] and transport and navigation [4]. More specifically, imaging through nebulous media encountered in nature, like fog, rain and light haze is still a topical issue that attracts a lot of attention.…”

Section: Introductionmentioning

confidence: 99%

Long-range polarimetric imaging through fog

et al. 2014

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We report an experimental implementation of long-range polarimetric imaging through fog over kilometric distance in real field atmospheric conditions. An incoherent polarized light source settled on a telecommunication tower is imaged at a 1.3 km distance with a snapshot polarimetric camera including a birefringent Wollaston prism, allowing simultaneous acquisition of two images along orthogonal polarization directions. From a large number of acquisitions datasets and under various environmental conditions (clear sky/fog/haze, day/night), we compare the efficiency of using polarized light for source contrast increase with different signal representations (intensity, polarimetric difference, polarimetric contrast,...). With the limited-dynamics detector used, a maximum fourfold increase in contrast was demonstrated under bright background illumination using polarimetric difference image. OCIS codes:(110.0113) Imaging through turbid media; (110.5405) Polarimetric imaging; (010.7295) Visibility and imaging; (110.4280 Noise in imaging systems).http://dx

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<title>Navigation through fog using stereoscopic active imaging</title>

Cited by 9 publications

References 0 publications

An all-optical technique enables instantaneous single-shot demodulation of images at high frequency

An all-optical technique enables instantaneous single-shot demodulation of images at high frequency

Theoretical optimal modulation frequencies for scattering parameter estimation and ballistic photon filtering in diffusing media

Long-range polarimetric imaging through fog

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