BIOMEDICAL IMAGING GROUP (BIG)
Laboratoire d'imagerie biomédicale (LIB)

High-Quality Parallel-Ray x-Ray CT Back Projection Using Optimized Interpolation

M.T. McCann, M. Unser

IEEE Transactions on Image Processing, vol. 26, no. 10, pp. 4639-4647, October 2017.

We propose a new, cost-efficient method for computing back projections in parallel-ray X-ray CT. Forward and back projections are the basis of almost all X-ray CT reconstruction methods, but computing these accurately is costly. In the special case of parallel-ray geometry, it turns out that reconstruction requires back projection only. One approach to accelerate the back projection is through interpolation: fit a continuous representation to samples of the desired signal, then sample it at the required locations. Instead, we propose applying a prefilter that has the effect of orthogonally projecting the underlying signal onto the space spanned by the interpolator, which can significantly improve the quality of the interpolation. We then build on this idea by using oblique projection, which simplifies the computation while giving effectively the same improvement in quality. Our experiments on analytical phantoms show that this refinement can improve the reconstruction quality for both filtered back projection and iterative reconstruction in the high-quality regime, i.e., with low noise and many measurements. 

@ARTICLE(http://bigwww.epfl.ch/publications/mccann1701.html,
AUTHOR="McCann, M.T. and Unser, M.",
TITLE="High-Quality Parallel-Ray {x}-Ray {CT} Back Projection Using
	Optimized Interpolation",
JOURNAL="{IEEE} Transactions on Image Processing",
YEAR="2017",
volume="26",
number="10",
pages="4639--4647",
month="October",
note="")

© 2017 The Authors CC-BY. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from The Authors CC-BY. This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.