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30 April 2007 Electronic zoom functionality in under-sampled imaging systems
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US Army thermal target acquisition models based on the Johnson metric do not accurately predict sensor performance with electronic zoom (E-zoom). For this reason, NVTherm2002 removed the limiting E zoom Modulation Transfer Functions (MTF) to agree better with measured performance results. In certain scenarios, especially with under-sampled staring sensors, the model shows incorrect performance improvements with E-zoomed images. The current Army model NVThermIP, based upon the new targeting task performance (TTP) metric, more accurately models range performance in these cases. E-zoom provides system design flexibility when limited to a single optical field-of-view and/or eye distance is constrained by ergonomic factors. This paper demonstrates that targeting acquisition range performance, modeled using the TTP metric, shows increases only up to an optimized magnification and then decreases beyond this optimal value. A design "rule of thumb" is provided to determine this optimal magnification. NVThermIP modeled range performance is supported with E-zoom perception experiment results.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Stephen D. Burks, Joseph P. Reynolds, Jonathan Hixson, Brian Teaney, and Richard Vollmerhausen "Electronic zoom functionality in under-sampled imaging systems", Proc. SPIE 6543, Infrared Imaging Systems: Design, Analysis, Modeling, and Testing XVIII, 65430M (30 April 2007);

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