Focal Plane Array Design For Optimum System Performance

Donald E. Marshall Jr.

doi:10.1117/12.958723

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24 June 1980 Focal Plane Array Design For Optimum System Performance

Donald E. Marshall Jr.

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Proceedings Volume 0226, Infrared Imaging Systems Technology; (1980) https://doi.org/10.1117/12.958723
Event: 1980 Technical Symposium East, 1980, Washington, D.C., United States

Abstract

Analytical expressions have been derived to simplify the design process for integrated focal planes. The focal plane parameters (detector size and CTD integration interval) are computed which peak system performance at a specific spatial frequency (fd). The spatial frequency is selected on the basis of target size and range and on an empirically derived relationship between recognition probability and cycles across the target. It is shown that a rectangular detector should have an angular subtense equal to 0.371/fd and that an ellptical detector should have a maximum dimension equal to 0.427/fd. In the case where a focal plane CTD integrator limits the electronics bandwidth, the optimum integration and sample interval is also 0.371/fd indicating that best performance is at one sample per detector dwell time. If a boxcar function is used in the scan direction for the display, and has a hold interval equal to the integration interval, the optimum integration and sample interval is 0.269/fd or 1.4 samples per dwell for the rectangular detector. The elliptical detector has slightly improved MRT and is slightly larger than the optimum rectangular detector. It has fabrication advantages for focal plane arrays using photovoltaic detectors. Signal aliasing is treated as a random noise source based on the fact that its impact on signal distortion is a function of the arbitrary phase relationship of the signal frequency and the sampling frequency. This model can be used to predict the MRT loss due to aliasing as a function of spatial frequency. At the design frequency (fd) a 5 percent loss in MRT is obtained for a rectangular detector and one sample per detector dwell time.

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Donald E. Marshall Jr. "Focal Plane Array Design For Optimum System Performance", Proc. SPIE 0226, Infrared Imaging Systems Technology, (24 June 1980); https://doi.org/10.1117/12.958723

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