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X‐ray scatter removal by deconvolution
Author(s) -
Seibert J. A.,
Boone J. M.
Publication year - 1988
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.596208
Subject(s) - deconvolution , optics , point spread function , imaging phantom , physics , optical transfer function , gaussian , projection (relational algebra) , iterative reconstruction , computed radiography , image quality , mathematics , artificial intelligence , algorithm , computer science , image (mathematics) , quantum mechanics
The distribution of scattered x rays detected in a two‐dimensional projection radiograph at diagnostic x‐ray energies is measured as a function of field size and object thickness at a fixed x‐ray potential and air gap. An image intensifier–TV based imaging system is used for image acquisition, manipulation, and analysis. A scatter point spread function (PSF) with an assumed linear, spatially invariant response is modeled as a modified Gaussian distribution, and is characterized by two parameters describing the width of the distribution and the fraction of scattered events detected. The PSF parameters are determined from analysis of images obtained with radio‐opaque lead disks centrally placed on the source side of a homogeneous phantom. Analytical methods are used to convert the PSF into the frequency domain. Numerical inversion provides an inverse filter that operates on frequency transformed, scatter degraded images. Resultant inverse transformed images demonstrate the nonarbitrary removal of scatter, increased radiographic contrast, and improved quantitative accuracy. The use of the deconvolution method appears to be clinically applicable to a variety of digital projection images.