The geographic lines of the land borders between the United States and Mexico total over 6,000 miles. The vast majority of those borders are in difficult to reach remote landscape. This makes it nearly impossible to patrol with any reasonable amount of personal or budget. Thus, the primary approach has been to mix a combination of low cost acoustic/seismic sensors with remotely controlled EO cameras. While moderately successful in controlled locations, these systems are expensive to install and expensive to man. The cost of these systems rises further when operation is required in night and adverse weather conditions. A lower cost of installation and maintenance could be achieved with miniaturized EO/IR cameras combined with intelligent remote and central processing. Advances in both VNIR and LW infrared sensors and developments in integrated signal processing now make possible a distributed low cost surveillance system. The ability now exists to detect, track, and classify people and equipment prior to notification of the responding agent.
This paper reports on the development of a new class of thermal cameras. Known as the FLAsh STabilized (FLAST) thermal imaging camera systme, these cameras are the first to be able to capture snapshop thermal images. Results from testing of the prototype unit will be presented and status on the design of amore efficient, miniaturized version for produciotn. The camera is highly programmable for images capture method, shot sequence, and shot quantity. To achieve the ability to operate in a snapship mode, the FLAST camera is designed to function without the need for cooling or other thermal regulation. In addition, the camera can operate over extended periods without the need for re-calibration. Thus, the cemera does not require a shutter, chopper or user inserted imager blocking system. This camera is capable operating for weeks using standard AA batteries. The initial camera configuration provides an image resolution of 320 x 240 and is able to turn-on and capture an image within approximately 1/4 sec. The FLAST camera operates autonomously, to collect, catalog and store over 500 images. Any interface and relay system capable of video formatted input will be able to serve as the image download transmission system.
Irvine Sensors Corporation (ISC) has pioneered the use of a chip stacking technology that allows an entire electronics system to be packaged into a single 3-dimensional cube of electronics. This stacking approach allows the elimination of traditional printed circuit boards (PCB) and as a result significantly reduces the size of the electronics. Recently this technology has been applied to electronic camera applications including both high-resolution digital still picture and video camera technologies. In addition this electronics implementation approach is under evaluation for application in the SWIR and LWIR/thermal imaging spectral bands.
Pressures to increase resolution, achieve compact packages, and lower costs continue to drive focal plane readout circuits to highly complex designs with lowered yields in cutting edge processes. By designing a set of signal processing electronics into a 3D structure, cost and performance goals can be met while using higher yielding readouts and existing focal plane hybrids. The approach described in this paper allows existing designs from 480 X 4 through 480 X 640 to be used in compact sensor designs in a wide variety of applications. The demonstration of the approach uses an existing InSb photovoltaic hybrid array in a 120 X 160 configuration. Functions for non- uniformity correction, memory, and analog-to-digital conversion have been incorporated into a structure compatible with conventional dewar assemblies for military and commercial applications. The technology for these 3D focal planes is applicable to sensor functions for non- uniformity correction, analog-to-digital conversion, spatial and temporal filtering, fovea vision, event-driven multiplexing, data compression and coding, and pattern recognition.
A variety of projects have been recently completed or are underway that utilize 3D architectures to achieve major enhancements of focal plane array signal processing capabilities. Progress will be presented in the areas of non-uniformity correction analog-to- digital conversion, spatial and temporal filtering, foveal vision, event-driven multiplexing, and neural pattern recognition. This progress is the result of on-going collaborative and individual efforts under direction of the authors.