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Recovery of Damped Exponentials Using Structured Low Rank Matrix Completion
Journal article   Open access   Peer reviewed

Recovery of Damped Exponentials Using Structured Low Rank Matrix Completion

Arvind Balachandrasekaran, Vincent Magnotta and Mathews Jacob
IEEE transactions on medical imaging, Vol.36(10), pp.2087-2098
10/2017
DOI: 10.1109/TMI.2017.2726995
PMCID: PMC5821149
PMID: 28715328
url
https://www.ncbi.nlm.nih.gov/pmc/articles/5821149View
Open Access

Abstract

We introduce a structured low rank matrix completion algorithm to recover a series of images from their under-sampled measurements, where the signal along the parameter dimension at every pixel is described by a linear combination of exponentials. We exploit the exponential behavior of the signal at every pixel, along with the spatial smoothness of the exponential parameters to derive an annihilation relation in the Fourier domain. This relation translates to a low-rank property on a structured matrix constructed from the Fourier samples. We enforce the low-rank property of the structured matrix as a regularization prior to recover the images. Since the direct use of current low rank matrix recovery schemes to this problem is associated with high computational complexity and memory demand, we adopt an iterative re-weighted least squares algorithm, which facilitates the exploitation of the convolutional structure of the matrix. Novel approximations involving 2-D fast Fourier transforms are introduced to drastically reduce the memory demand and computational complexity, which facilitates the extension of structured low-rank methods to large scale 3-D problems. We demonstrate our algorithm in the MR parameter mapping setting and show improvement over the state-of-the-art methods.
Jacobian matrices Hankel/Toeplitz matrix Convolution smoothness Two dimensional displays Discrete Fourier transforms regularized recovery Approximation algorithms Indexes Computational complexity parameter mapping

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