Dynamic Laser Speckle Imaging (dLSI)

Laser speckle imaging (LSI) based on the speckle contrast analysis is a simple and robust technique for imaging of heterogeneous dynamics. LSI finds frequent application for dynamical mapping of cerebral blood flow, as it features high spatial and temporal resolution. However, the quantitative interpretation of the acquired data is not straightforward for the common case of a speckle field formed by mixture of dynamic and static scatterers such as blood cells and bone or tissue. We have proposed a novel scheme for speckle data analysis, called dynamic laser speckle imaging (dLSI), that can be used to correctly extract the temporal correlation parameters from the speckle contrast measured in the presence of a static or slow-evolving background.

The static light contribution is derived from the measurements by cross-correlating sequential speckle images. In-vivo speckle imaging experiments performed in the rodent brain demonstrate that dLSI leads to improved results. The cerebral hemodynamic response observed through the

thinned and intact skull are more pronounced in the dLSI images as compared to the standard speckle contrast analysis. The proposed method also yields benefits with respect to the quality of the speckle images by suppressing contributions of non-uniformly distributed specular reflections.

The Matlab code for the implementation of dLSI method with examples can be downloaded from this link: dLSI-03.02.zip . The file is password protected, but you can obtain it from me, by sending a short email to pv.zakharov at gmail.com. Kindly indicate your university/industry affiliation and a brief description of how you plan to use the code.

The test dataset can be downloaded from this page: Test dataset for dLSI code. The expected results are displayed below:

The fast Matlab code for the plan contrast analysis is available here from my blog post Fast Laser Speckle Contrast Calculation

References

1. "Dynamic laser speckle imaging of cerebral blood flow", P. Zakharov, A.C. Völker, M.T. Wyss, F. Haiss, N. Calcinaghi, C. Zunzunegui, A. Buck, F. Scheffold, B. Weber, Optics Express, 2009;17(16):13904-17 [PDF]