C-RED 3: A SWIR camera for FSO applications

Gach, Jean-Luc; Boutolleau, David; Brun, Cecile; Carmignani, Thomas; Clop, Fabien; Feautrier, Philippe; Lemarchand, Stéphane; Stadler, Eric; Wanwanscappel, Yann

doi:10.1117/12.2545823

Cited by 4 publications

(5 citation statements)

References 12 publications

(14 reference statements)

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“…The WFS detector was a First Light Imaging CRED-3 Indium Gallium Arsenide (InGaAs) camera [10] with a bandpass of 900-1700 nm. The optical design of the 24hSHIMM is shown in Fig.…”

Section: The 24hshimmmentioning

confidence: 99%

“…This was greater than the daytime sky background noise. The CRED-3 camera was chosen due to its high linearity and suitability for wavefront sensing applications [10]. The camera is uncooledreducing weight and expense, however by running at the very short exposure times required for wavefront sensing, the increased contribution of dark current to the detector noise as a result of higher sensor temperature is minimised.…”

Section: Shack-hartmann Daytime Image Analysismentioning

confidence: 99%

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Demonstrating the first 24-hour continuous vertical monitoring of the atmospheric optical turbulence

Griffiths¹,

Osborn²,

Farley³

et al. 2023

Preprint

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We report what is believed to be the first example of fully continuous, 24-hour vertical monitoring of atmospheric optical turbulence. This is achieved using a novel instrument, the 24-hour Shack-Hartmann Image Motion Monitor (24hSHIMM). Optical turbulence is a fundamental limitation for applications such as free-space optical communications, where it limits the achievable bandwidth, and ground-based optical astronomy, restricting the observational precision. Knowledge of the turbulence enables us to select the best sites, design optical instrumentation and optimise the operation of ground-based optical systems. To illustrate our advance we show a 35-hour continuous measurement of the vertical optical turbulence coherence length, time and angle, the Rytov variance and a four-layer vertical profile. Due to its portability and ability to work in stronger turbulence, the 24hSHIMM can also operate in urban locations. We show that this single instrument can replace the large number of turbulence measurement solutions, providing the field with a single optical turbulence monitor, for all but the most demanding of applications.

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“…The WFS detector was a First Light Imaging CRED-3 Indium Gallium Arsenide (InGaAs) camera [10] with a bandpass of 900-1700 nm. The optical design of the 24hSHIMM is shown in Fig.…”

Section: The 24hshimmmentioning

confidence: 99%

Section: Shack-hartmann Daytime Image Analysismentioning

confidence: 99%

Demonstrating the first 24-hour continuous vertical monitoring of the atmospheric optical turbulence

Griffiths¹,

Osborn²,

Farley³

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…For autoguiding, a SkyWatcher Evoguide 50ED guidescope was paired with a ZWO ASI462MC CMOS camera (60% QE at 850 nm) and an 850 nm longpass filter to block visible wavelengths. The WFS detector was a First Light Imaging CRED-3 Indium Gallium Arsenide (InGaAs) camera [10] with a bandpass of 900-1700 nm. The optical design of the 24hSHIMM is shown in Fig.…”

Section: The 24hshimmmentioning

confidence: 99%

Demonstrating the first 24-hour continuous vertical monitoring of the atmospheric optical turbulence

Griffiths¹,

Osborn²,

Farley³

et al. 2023

Preprint

View full text Add to dashboard Cite

We report what is believed to be the first example of fully continuous, 24-hour vertical monitoring of atmospheric optical turbulence. This is achieved using a novel instrument, the 24-hour Shack-Hartmann Image Motion Monitor (24hSHIMM). Optical turbulence is a fundamental limitation for applications such as free-space optical communications, where it limits the achievable bandwidth, and ground-based optical astronomy, restricting the observational precision. Knowledge of the turbulence enables us to select the best sites, design optical instrumentation and optimise the operation of ground-based optical systems. The 24hSHIMM estimates the vertical optical turbulence coherence length, time, angle and Rytov variance from the measurement of a four-layer vertical turbulence profile and a wind speed profile retrieved from meteorological forecasts. To illustrate our advance we show the values of these parameters recorded during a 35-hour, continuous demonstration of the instrument. Due to its portability and ability to work in stronger turbulence, the 24hSHIMM can also operate in urban locations, providing the field with a truly continuous, versatile turbulence monitor for all but the most demanding of applications.

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“…With advancements in camera sensor technology for remote sensing, there has been growing interest in the usage of short-wave infrared (SWIR) bands [13]. The SWIR spectrum is a frequency band located between the visible and mid-infrared bands of the electromagnetic spectrum, and it has a wavelength range of about 1-3 µm [14].…”

Section: Introductionmentioning

confidence: 99%

“…The SWIR spectrum is a frequency band located between the visible and mid-infrared bands of the electromagnetic spectrum, and it has a wavelength range of about 1-3 µm [14]. Compared to visible bands, SWIR bands are less impacted by atmospheric scattering and absorption [13]; thus, a SWIR camera is used at the GS to capture LEO satellites as small targets in infrared images.…”

Section: Introductionmentioning

confidence: 99%

Deep Learning-Based Small Target Detection for Satellite–Ground Free Space Optical Communications

Devkota,

Kim

2023

Electronics

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Free space optical (FSO) channels between a low earth orbit (LEO) satellite and a ground station (GS) use a highly directional optical beam that necessitates a continuous line-of-sight (LOS) connection. In this paper, we propose a deep neural network (DNN)-based small target detection method that detects the position of a LEO satellite in an infrared image, which can be used to determine the receiver alignment for establishing the LOS link. For the infrared small target detection task without excessive down-sampling, we design a target detection model using a modified ResNest-based feature extraction network (FEN), a custom feature pyramid network (FPN), and a target determination network (TDN). ResNest utilizes the feature map attention mechanism and multi-path propagation necessary for robust feature extraction of small infrared targets. The custom FPN combines multi-scale feature maps generated from the modified ResNest to obtain robust semantics across all scales. Finally, the semantically strong multi-scale feature maps are fed into the TDN to detect small infrared targets and determine their location in infrared images. Experimental results using two widely used point spread functions (PSFs) demonstrate that the proposed algorithm outperforms the conventional schemes and detects small targets with a true detection rate of 99.4% and 94.0%.

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C-RED 3: A SWIR camera for FSO applications

Cited by 4 publications

References 12 publications

Demonstrating the first 24-hour continuous vertical monitoring of the atmospheric optical turbulence

Demonstrating the first 24-hour continuous vertical monitoring of the atmospheric optical turbulence

Demonstrating the first 24-hour continuous vertical monitoring of the atmospheric optical turbulence

Deep Learning-Based Small Target Detection for Satellite–Ground Free Space Optical Communications

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