Superresolution of Passive Millimeter-Wave Imaging
AUBURN UNIV AL
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In standard intensity imaging, the resolution is limited by the width of the aperture. The region of support of the autocorrelation of the pupil function is the measured spatial frequency bandwidth of the imaging system and thus determines the resolution limit. This relationship between the size of the pupil function and the resolution limit is generally taken to describe a fundamental limit for resolution. Contrary to conventional wisdom, the resolution is actually limited only for fields with zero higher-order cumulants. For fields with non-vanishing higher-order cumulants, higher resolution can be obtained by integrating higher powers of instantaneous intensity in the image plane and combining these images appropriately. The result is that resolution is limited only by the time required for the integral of the higher power of intensity to approximate the expected value. We demonstrate these claims and analyze the variance of the integrated intensity-squared image as a function of the temporal spectrum and integration time. Furthermore, various image restoration strategies are proposed to estimate the superresolved intensity image from the various measurements. Our simulations show imaging of spatial frequency information outside the support of the pupil function autocorrelation for non-Gaussian fields.