
doi: 10.1137/1028005
This paper suggests one possible approach to demonstrating how to invert the Radon transform, in a language accessible to senior undergraduates in the mathematical sciences, from a new, rigorous point of view that closely parallels actual numerical methods, and involves only calculus. The present approach relies on a simple inversion formula, based on a well-known convolution technique first formulated by Z. H. Cho in 1974, but accomplished by him with numerical approximations only [see \textit{Z. H. Cho} et al., Computerized image reconstruction methods with multiple photon/X-ray transmission scanning, Phys. Med. Biol., 19, 511-522 (1974), p. 517 and \textit{Z. H. Cho}, General views on 3-D image reconstruction and computerized transverse axial tomography, IEEE Trans. Nucl. Sci., NS-21, 44-71 (1974), p. 62]. Briefly, the present method involves an auxiliary function \(G_ c\), which depends on a positive parameter, c; given the Radon transform, \({\mathcal R}f\), of some function, f, the function \(G_ c\) recovers f as follows. \[ Theorem: f(x,y)=\lim_{c\to 0}\frac{1}{\pi}\int^{\pi}_{0}\int^{\infty}_{-\infty}{\mathcal R}f(p-x \cos \alpha -y \sin \alpha,\alpha)G_ c(p)dp d\alpha. \] In this inversion formula, the double integral on the right-hand side is an ordinary improper Riemann integral that equals, rather than merely approximates, the average of f over the disc of radius c centered at (x,y). The novel contribution of this paper is to exhibit an explicit expression for the convolution kernel \(G_ c\) and utilize it for didactic purposes.
reconstruction filter, Medical applications (general), inversion formula, transfer function, Special integral transforms (Legendre, Hilbert, etc.), Numerical methods for integral equations, Integral equations with miscellaneous special kernels, Numerical methods for integral transforms, Radon transform
reconstruction filter, Medical applications (general), inversion formula, transfer function, Special integral transforms (Legendre, Hilbert, etc.), Numerical methods for integral equations, Integral equations with miscellaneous special kernels, Numerical methods for integral transforms, Radon transform
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