Adaptive coded apertures: bridging the gap between non-diffractive and diffractive imaging systems

Gottesman, Stephen R.; Isser, Abraham; Gigioli, George W.

doi:10.1117/12.863032

Cited by 4 publications

(1 citation statement)

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“…Gottesman proposed his design succeed with the conventional coded aperture in heavy ray imaging [5], which the detected images are geometric projections of the source point light pre-coded by the mask pattern. Therefore, the diffraction of infrared with longer wavelength was not considered in the initial design, but was included into his following works to estimate systems' imaging resolution [2,13,14]. The QinetiQ Company was inspired by the compound eye systems in biology and hence regarded the coded aperture imaging as a system of multi-pinhole imaging with recovery algorithms of image fusion.…”

Section: Introductionmentioning

confidence: 99%

A model of PSF estimation for coded mask infrared imaging

et al. 2014

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The point spread function (PSF) of imaging system with coded mask is generally acquired by practical measurement with calibration light source. As the thermal radiation of coded masks are relatively severe than it is in visible imaging systems, which buries the modulation effects of the mask pattern, it is difficult to estimate and evaluate the performance of mask pattern from measured results. To tackle this problem, a model for infrared imaging systems with masks is presented in this paper. The model is composed with two functional components, the coded mask imaging with ideal focused lenses and the imperfection imaging with practical lenses. Ignoring the thermal radiation, the systems PSF can then be represented by a convolution of the diffraction pattern of mask with the PSF of practical lenses. To evaluate performances of different mask patterns, a set of criterion are designed according to different imaging and recovery methods. Furthermore, imaging results with inclined plane waves are analyzed to achieve the variation of PSF within the view field. The influence of mask cell size is also analyzed to control the diffraction pattern. Numerical results show that mask pattern for direct imaging systems should have more random structures, while more periodic structures are needed in system with image reconstruction. By adjusting the combination of random and periodic arrangement, desired diffraction pattern can be achieved.

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