Fractality of pulsatile flow in speckle images

Fractality of pulsatile flow in speckle images

Nemati, M. (TU Delft ImPhys/Optics)
Kenjeres, S. (TU Delft ChemE/Transport Phenomena)
Urbach, Paul (TU Delft ImPhys/Optics)
Bhattacharya, N. (TU Delft ImPhys/Optics)

2016-05-02

The scattering of coherent light from a system with underlying flow can be used to yield essential information about dynamics of the process. In the case of pulsatile flow, there is a rapid change in the properties of the speckle images. This can be studied using the standard laser speckle contrast and also the fractality of images. In this paper, we report the results of experiments performed to study pulsatile flow with speckle images, under different experimental configurations to verify the robustness of the techniques for applications. In order to study flow under various levels of complexity, the measurements were done for three in-vitro phantoms and two in-vivo situations. The pumping mechanisms were varied ranging from mechanical pumps to the human heart for the in vivo case. The speckle images were analyzed using the techniques of fractal dimension and speckle contrast analysis. The results of these techniques for the various experimental scenarios were compared. The fractal dimension is a more sensitive measure to capture the complexity of the signal though it was observed that it is also extremely sensitive to the properties of the scattering medium and cannot recover the signal for thicker diffusers in comparison to speckle contrast.

Speckle
Fractals
Flow visualization
Time series analysis
Medical imaging

http://resolver.tudelft.nl/uuid:f9780e01-ce62-45c4-b440-d101863ed37d

https://doi.org/10.1063/1.4948297

2017-05-02

0021-8979

Journal of Applied Physics, 119 (17)

Institutional Repository

journal article

© 2016 M. Nemati, S. Kenjeres, Paul Urbach, N. Bhattacharya