23 November 1982 Measurement Of Optical Modulation Functions In Sparsely Sampled Mosaic Focal Plane Arrays
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Abstract
When individual detectors in scanned focal plane arrays are sampled at a rate of once per instantaneous field of view (IFOV), a problem arises in measuring detector optical modulation functions, (SWR, MTF). Ideally, one would like to pass a slit illumination or knife edge illumination across an IFOV, generating respectively, a line spread function or knife edge response curve from which optical modulation could be calculated versus spatial frequency. Use of sampling phase delays is a possible solution, but is subject to phase errors resulting from scan rate variations. The method described here is a "phased knife edge" approach. It employs a multi-bar reticle image, designed so that successive bar edges are slightly shifted in phase with respect to an IFOV area as the IFOV signal is sampled during a single scan. The resulting data, after conversion to a knife edge response function, is convolved with a sliding phase, computer-generated square wave image to find SWR versus spatial frequency. MTF is obtained by converting the knife edge response to a line spread function and applying standard algorithms for convolution of the LSF with sinusoidal bar patterns of desired spatial frequency.
© (1982) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
J. B. Young, J. B. Young, P. E. Thurlow, P. E. Thurlow, } "Measurement Of Optical Modulation Functions In Sparsely Sampled Mosaic Focal Plane Arrays", Proc. SPIE 0345, Advanced Multispectral Remote Sensing Technology and Applications, (23 November 1982); doi: 10.1117/12.933774; https://doi.org/10.1117/12.933774
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