Dependence of photoacoustic speckles on boundary roughness

Zijian Guo; Zhun Xu; Lihong V. Wang

doi:10.1117/1.JBO.17.4.046009

19 April 2012 Dependence of photoacoustic speckles on boundary roughness

Zijian Guo, Zhun Xu, Lihong V. Wang

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Journal of Biomedical Optics, Vol. 17, Issue 4, 046009 (April 2012). https://doi.org/10.1117/1.JBO.17.4.046009

Abstract

Speckles have been considered ubiquitous in all scattering-based coherent imaging technologies. However, as an optical-absorption-based coherent imaging technology, photoacoustic (PA) tomography (PAT) suppresses speckles by building up prominent boundary signals. We theoretically study the dependence of PAT speckles on the boundary roughness, which is quantified by the root-mean-squared value and the correlation length of the boundary height. Both the speckle visibility and the correlation coefficient between the reconstructed and actual boundaries are quantified. If the root-mean-squared height fluctuation is much greater than, and the height correlation length is much smaller than the imaging resolution, the reconstructed boundaries become fully developed speckles. In other words, speckle formation requires large uncorrelated height fluctuations within the resolution cell. The first- and second-order statistics of PAT speckles are also studied experimentally. While the amplitude of the speckles follows a Gaussian distribution, the autocorrelation of the speckle patterns tracks that of the system point spread function.

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Zijian Guo, Zhun Xu, and Lihong V. Wang "Dependence of photoacoustic speckles on boundary roughness," Journal of Biomedical Optics 17(4), 046009 (19 April 2012). https://doi.org/10.1117/1.JBO.17.4.046009

Published: 19 April 2012

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