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Journal of Biomedical Optics • Open Access

On the use of the Cramér–Rao lower bound for diffuse optical imaging system design
Author(s): Vivian E. Pera; Dana H. Brooks; Mark J. Niedre

Paper Abstract

We evaluated the potential of the Cramér–Rao lower bound (CRLB) to serve as a design metric for diffuse optical imaging systems. The CRLB defines the best achievable precision of any estimator for a given data model; it is often used in the statistical signal processing community for feasibility studies and system design. Computing the CRLB requires inverting the Fisher information matrix (FIM), however, which is usually ill-conditioned (and often underdetermined) in the case of diffuse optical tomography (DOT). We regularized the FIM by assuming that the inhomogeneity to be imaged was a point target and assessed the ability of point-target CRLBs to predict system performance in a typical DOT setting in silico. Our reconstructions, obtained with a common iterative algebraic technique, revealed that these bounds are not good predictors of imaging performance across different system configurations, even in a relative sense. This study demonstrates that agreement between the trends predicted by the CRLBs and imaging performance obtained with reconstruction algorithms that rely on a different regularization approach cannot be assumed a priori. Moreover, it underscores the importance of taking into account the intended regularization method when attempting to optimize source–detector configurations.

Paper Details

Date Published: 6 February 2014
PDF: 8 pages
J. Biomed. Opt. 19(2) 025002 doi: 10.1117/1.JBO.19.2.025002
Published in: Journal of Biomedical Optics Volume 19, Issue 2
Show Author Affiliations
Vivian E. Pera, Northeastern Univ. (United States)
Dana H. Brooks, Northeastern Univ. (United States)
Mark J. Niedre, Northeastern Univ. (United States)


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