Infrared hyperspectral imagers (HSI) have been fielded for the detection of hazardous chemical and biological compounds, tag detection (friend versus foe detection) and other defense critical sensing missions over the last two decades. Low Size/Weight/Power/Cost (SWaPc) methods of identification of chemical compounds spectroscopy has been a long term goal for hand held applications. We describe a new HSI concept for low cost / high performance InGaAs SWIR camera chemical identification for military, security, industrial and commercial end user applications. Multivariate Optical Elements (MOEs) are thin-film devices that encode a broadband, spectroscopic pattern allowing a simple broadband detector to generate a highly sensitive and specific detection for a target analyte. MOEs can be matched 1:1 to a discrete analyte or class prediction. Additionally, MOE filter sets are capable of sensing an orthogonal projection of the original sparse spectroscopic space enabling a small set of MOEs to discriminate a multitude of target analytes. This paper identifies algorithms and broadband optical filter designs that have been demonstrated to identify chemical compounds using high performance InGaAs VGA detectors. It shows how some of the initial models have been reduced to simple spectral designs and tested to produce positive identification of such chemicals. We also are developing pixilated MOE compressed detection sensors for the detection of a multitude of chemical targets in challenging backgrounds/environments for both commercial and defense/security applications. This MOE based, real-time HSI sensor will exhibit superior sensitivity and specificity as compared to currently fielded HSI systems.
A new detection system has been designed and constructed that enables remote sensing, recording and archiving of
Electrical Over-Stress (EOS) and Electro Static Discharge (ESD) events, a major cause of electronic device failure in
ruggedized military applications. Advances have been made in the design and manufacture of magneto-optic static event
detection devices and in the ability to perform automatic detection of polarization states of the devices. The combined
automatic reader and next-generation device are providing viable prototypes for insertion into legacy circuit boards for
EOS and ESD monitoring.
Current mid-wave infrared detector technologies, such as Indium Antimonide, Mercury Cadmium Telluride, and Platinum Silicide, require the use of expensive, heavy, and power hungry cryogenic coolers or expensive multistage thermoelectric coolers. There is a need for a low cost uncooled mid-wave infrared (MWIR) technology for use in applications where cost, power, size, and reliability are of most importance. Northrop Grumman Electro-Optical Systems (EOS) is currently developing such a sensor based upon its low cost Lead Selenide (PbSe) detector technology. Utilizing its extensive production experience in producing high performance linear PbSe arrays, EOS has developed a 320X256 staring PbSe Focal Plane Array. This paper provides a summary and status of the development efforts and associated performance of EOS' new PbSe FPA's.
In pursuit of a low cost, high performance IR, Imager Litton Electro-Optical Systems has developed an Uncooled Lead Salt 320 X 240 camera. The 30 um pitch detectors consist of either Lead Sulfide or Lead Selenide photoconductors fabricated onto a CMOS Multiplexer Read-Out Integrated circuit. The multiplexer uses novel techniques to subtract the large bias current adaptively, and to integrate the residual signal current. The image is acquired in `snapshot' mode. A chopper provides a uniform reference. Although not necessary for functionality, a thermo-electric cooler is incorporated to improve performance. The signal is digitized off focal plane, and pixel substitution/correction functions are subsequently performed. The resulting video signal is either observed on a LCD display at the back of the camera or remoted to an external viewing device.
The reflective magneto-optic spatial light modulator (R-MOSLM) device was developed over the past few years by a group of Litton divisions and Carnegie Mellon University. The device has been fabricated into 128 X 128 arrays on 24 micron pitch. The performance of individual devices has been reported in previous years. This paper describes the use of the device in an optical correlator. Litton has been developing the miniature ruggedized optical correlator (MROC) for use in a variety of pattern recognition applications. This paper discusses the packaging of the device, the drive electronics, and the interfacing of the device to the MROC unit.
This paper is a report on the characteristics of a new high resolution, high frame rate, reflected R-MOSLM. This effort is aimed at the production of Miniature Ruggedized Optical Correlators for Optical Pattern Recognition. Pixel size is under one mil center to center, one-third the dimension of present transmission mode devices, thereby reducing the optical path length by an order of magnitude. This development includes optimization of the optical and functional characteristics of the MOSLM for Mil Spec Systems.
The reflected mode magneto-optic spatial light modulator (R-MOSLM) has been developed over the past couple of years. This development has led to a device that has state-of-the-art performance and is producible. This SLM device is truly compatible with semiconductor manufacturing techniques and is now being fabricated in a production environment. Performance details of individual devices is presented elsewhere. However, in this paper we discuss the measured parameters of multiple devices for statistics, discuss yield and packaging, and describe the impact of its manufacturability on cost. The system description of the correlator system using these devices is reported in a companion paper.