Computer Model of a Passive Synthetic Aperture Imaging System
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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This thesis was concerned with the development of a computer model of a passive synthetic aperture imaging system. The research was divided into three parts. They were 1 applying an understanding of partial coherence theory and its relationship to the impulse response of the system, 2 developing the computer model, and 3 exercising the computer model to perform a sensitivity analysis. The system modeled consisted of two lenses mounted on a movable platform. The lenses were separated by a fixed distance and travelled in a direction parallel to this separation. The coherence of radiation present at each lens emanating from a real source was measured yielding the Fourier transform of the source intensity distribution according to the van Cittert-Zernike theorem 2510. The transform was then multiplied by an effective aperture obtained from the motion and position of the lenses relative to the source. An inverse Fourier transform was then applied to this result yielding the image. This is the process modeled by the computer. The results indicated that new means of image interpretation must be developed in order to make the results useful. This is due to the fact that the system behaves much like a high pass filter and the image is edge enhanced and not a scaled version of the geometric image.