Space-Variant Image Formation*

Large-Scale Inverse Problems in Imaging

“…For example, in positron emission tomography (PET), patient motion during the relatively long scan times causes reconstructed images to be corrupted by nonlinear, nonuniform spatially variant motion blur [33,84]. Spatially variant blurs also occur when the object and image coordinates are tilted relative to each other, as well as in X-ray projection imaging [100], lens distortions [65], and wave aberrations [65]. Moreover, it is unlikely that the blur is truly spatially invariant in any realistic application, especially over large image planes.…”

Efficient filter flow for space-variant multiframe blind deconvolution

“…The next step is to consider blurs that are spatially-variant (though often a localinvariance is assumed). Early relevant work includes [20], where the authors cleanly formalize space-variant imaging systems, and discuss basic special cases such as: piecewise space-invariant systems and geometric distortion.…”

Integration of segmented 3D image data measured by projected fringe profilometry

“…Because of the field dependence of the aberrations, the imaging system is spatially variant in a strict sense [12]. However, within some small areas, the imaging system is approximately spatially invariant.…”

“…However, within some small areas, the imaging system is approximately spatially invariant. In other words, all aberrations are approximately constant in a piecewise manner (isoplanatism assumption) [12]. With this simplification, the image irradiance g (x', y') can be expressed as gç(x',y') = fr(X',Y')® hr(X',Y'), (3.1) where hr (', y') represents the point spread function of the aberrated imaging system and Jr (x', y') represents the rescaled and distorted replica ofthe object radiance distribution f(x, y),…”