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RESOLUTION PERFORMANCE IMPROVEMENTS IN STARING IMAGING SYSTEMS USING
MICRO-SCANNING AND A RETICULATED, SELECTABLE FILL FACTOR InSb FPA
Mark E. Greiner, Mike Davis, and John G. Sanders
Cincinnati Electronics Corporation
As staring focal plane array (FPA) detectors continue to mature, FPA based IR imaging systems are
available in more compact packages that are lighter and consume less power than first or second generation scanning
IR sensor packages.
However, standard IR analysis models indicate that staring FPA based cameras, while having
excellent sensitivity, will have reduced resolution when compared to scanning systems with similar sized detector
elements and optics.
This apparent resolution limitation is created by the fixed sampling of the active pixel size native
to staring FPA systems.
Micro-scanning, a technique which moves the image in sub-pixel steps on the focal plane,
can provide some over-sampling and reduce this limitation.
Standard attempts at micro-scanning using 2-dimensional
starring arrays with near 100% fill factor produce only marginal improvements in resolution in these systems.
present here a new concept in micro-scanning using an InSb FPA with reticulated detector elements and active area
masking to provide a well defined, selectable fill factor.
A compact micro-scanned imaging system design that weighs less than 8 pounds and consumes less than
15 watts is presented here.
MRTD (Minimum Resolvable Temperature Difference) analyses demonstrating a 2X
improvement in resolution in both vertical and horizontal directions over non-micro-scanned systems has been
measured, a performance level which micro-scanned systems with non-reticulated FPAs cannot approach.
from this system will also be presented including NETD and MRTD performance.
In the last decade, Staring Focal Plan Array (FPA) based thermal imagers have shown a steady increase in
performance – in resolution, sensitivity, compactness of package, low power and in overall picture quality.
increase in performance is absorbed by the system user with a demand for even greater performance in the next
iteration of camera design.
Today, most of the improved system performance comes with the need for larger arrays,
larger substrates and larger dewar/cooler/array assemblies – at the cost of a more expensive array and a higher power
In 1997, Cincinnati Electronics Corp. (CE) developed a compact, low-cost, general purpose, MWIR imager
and demonstrated a significant improvement in most areas of system performance.
Called the NightConqueror
system, this compact, multipurpose thermal imaging sensor is capable of displaying images from many formats of
focal plane array (FPA) detectors.
The system can display images from high density 640 x 512 pixel FPAs, medium
density 256 x 256 or 320 x 240 pixel FPAs, or one or two axis micro-scanned medium density FPAs.