Advanced multifunctional detectors for laser-gated imaging applications

Baker, Ian; Thorne, Peter; Henderson, James L.; Copley, Jeremy; Humphreys, D.A.; Millar, Alasdair

doi:10.1117/12.673577

Cited by 21 publications

(8 citation statements)

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“…The SELEX-Galileo 3D detector has been described in previous papers 1,2,3,4 . Recent activity has concentrated on range trials for the prototype cameras and signal processing for the display of 3D information.…”

Section: Trials Experience Of Selex-galileo 3d Camerasmentioning

confidence: 99%

Developments in HgCdTe avalanche photodiode technology and applications

Ashcroft¹,

Baker²

2010

SPIE Proceedings

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SELEX Galileo has developed avalanche photodiode technology in HgCdTe to serve a whole range of applications in defence, security, commercial and space research. Burst-illumination LIDAR (BIL), using a near-infrared pulse laser and a fast, gated detector, is now adopted for most long range imaging applications. New results from range trials using prototype systems based on multifunctional and 3D detectors are reported. In the astronomy field, APD arrays at 2.5 μm cutoff can provide near-single photon sensitivity for future wavefront sensors and interferometric applications. Under a contract from European Southern Observatories arrays have been successfully demonstrated with gains up to 20× and negligible dark current at 77K. Under a European Space Agency contract, a large area, single element detector has been designed for the 2.015µm CO 2 absorption line. The sensor is specifically designed to be operated at 200K so that thermoelectric cooling is viable. The element is made up of many sub-pixel diodes each deselectable to ensure high breakdown in the macro-pixel. The latest results of the detector and its associated transimpedance amplifier (TIA) are presented.

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Section: Trials Experience Of Selex-galileo 3d Camerasmentioning

confidence: 99%

Developments in HgCdTe avalanche photodiode technology and applications

Ashcroft¹,

Baker²

2010

SPIE Proceedings

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“…In fact the incorporation of analogue circuitry in the pixel to produce a thermal imaging and a laser gated imaging functionality is only possible if some radical compaction strategies are used. The topomorphic design principle was described in our previous paper 3 . This approach has similarities to an uncommitted gate array in the digital world.…”

Section: Topomorphic Design For Multi-functional Detectorsmentioning

confidence: 99%

Advanced infrared detectors for multimode active and passive imaging applications

Baker¹,

Owton²,

Trundle³

et al. 2008

SPIE Proceedings

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Active systems, using a near-infrared pulse laser and a fast, gated detector, are now adopted for most long range imaging applications. This concept is often called laser-gated imaging (LGI) or burst-illumination LIDAR (BIL). The SELEX solid state detector is based on an array of HgCdTe avalanche photodiodes, and a custom-designed CMOS multiplexer to perform the fast gating and photon signal capture. This paper describes two recent developments. The first is aimed at reducing the size, weight, power and cost of steerable platforms which often have to contain a large number of electrooptic tools such as lasers, range finders, BIL, thermal imaging and visible cameras. A dual-mode infrared detector has been developed with the aim of shrinking the system to one camera. The detector can be switched to operate as a passive thermal imager, a laser-gated imager or a solar flux imager. The detector produces a sensitivity in the MW thermal band of 16-18mK and a sensitivity in the BIL mode as low as 10 photons rms, in other words close to the performance of dedicated imagers. A second development was to extend the current BIL capability to 3D. In complex scenes, with camouflage and concealment, the ability to generate 3D images provides a signal-to-clutter advantage. Also in airborne applications, especially, it is useful to have 3D information to provide agile, feedback control of the range gating in a dynamic environment. This report describes the development of the 3D detector and camera, and the results of field trials using a prototype system. INTRODUCTION TO LASER-GATED IMAGING AT SELEXThe benefits of laser-gated imaging (LGI) or burst-illumination LIDAR (BIL) have been established in the UK over the past 6 years in a large number of trials, encompassing ground-based, naval and airborne scenarios. The ability to perform detection, recognition, identification and intent over long ranges, day and night, is an essential modern requirement. Several factors give laser gated imaging a performance advantage. Firstly, a collimated, pulse laser can give instantaneous brightness levels far in excess of passive infrared emission levels even at extreme long range. The brightness levels allow the use of long focal length telescopes made from glass (because of the 1.55µm wavelength). Also at 1.55µm there is better optical resolution compared with the longer wavelengths of passive IR systems. It is therefore fairly straightforward to achieve resolution improvements of over an order of magnitude compared with standard thermal imaging. The temporal gating function can help to reduce clutter in the scene by extinguishing signals outside of the gate. Another advantage stems from the short laser pulse (typically 20ns wide) which has the effect of freezing the scene, including any own-platform jitter, and any atmospheric effects. There will be distortion from frame to frame but work at SELEX, Edinburgh has shown the images can be de-rotated and re-registered to restore stable images 1 .Previous papers on laser-gated imaging technology at ...

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“…The detector is a development of the SWIFT burst illumination laser detector [1]. The HgCdTe detector is designed for use with a 1.5µm laser and provides 320 x 256 pixel images.…”

Section: Description Of 3d Sensormentioning

confidence: 99%

Simulation of a new 3D imaging sensor for identifying difficult military targets

et al. 2008

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This paper reports the successful application of automatic target recognition and identification (ATR/I) algorithms to simulated 3D imagery of 'difficult' military targets. QinetiQ and Selex S&AS are engaged in a joint programme to build a new 3D laser imaging sensor for UK MOD. The sensor is a 3D flash system giving an image containing range and intensity information suitable for targeting operations from fast jet platforms, and is currently being integrated with an ATR/I suite for demonstration and testing.The sensor has been extensively modelled and a set of high fidelity simulated imagery has been generated using the CAMEO-SIM scene generation software tool. These include a variety of different scenarios (varying range, platform altitude, target orientation and environments), and some 'difficult' targets such as concealed military vehicles. The ATR/I algorithms have been tested on this image set and their performance compared to 2D passive imagery from the airborne trials using a Wescam MX-15 infrared sensor and real-time ATR/I suite.This paper outlines the principles behind the sensor model and the methodology of 3D scene simulation. An overview of the 3D ATR/I programme and algorithms is presented, and the relative performance of the ATR/I against the simulated image set is reported. Comparisons are made to the performance of typical 2D sensors, confirming the benefits of 3D imaging for targeting applications.

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Advanced multifunctional detectors for laser-gated imaging applications

Cited by 21 publications

References 0 publications

Developments in HgCdTe avalanche photodiode technology and applications

Developments in HgCdTe avalanche photodiode technology and applications

Advanced infrared detectors for multimode active and passive imaging applications

Simulation of a new 3D imaging sensor for identifying difficult military targets

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