Abstract
Laser speckle contrast imaging (LSCI) is a well-known and versatile approach for the non-invasive visualization of flows and microcirculation localized in turbid scattering media, including biological tissues. In most conventional implementations of LSCI the ergodic regime is typically assumed valid. However, most composite turbid scattering media, especially biological tissues, are non-ergodic, containing a mixture of dynamic and static centers of light scattering. In the current study, we examined the speckle contrast in different dynamic conditions with the aim of assessing limitations in the quantitative interpretation of speckle contrast images. Based on a simple phenomenological approach, we introduced a coefficient of speckle dynamics to quantitatively assess the ratio of the dynamic part of a scattering medium to the static one. The introduced coefficient allows one to distinguish real changes in motion from the mere appearance of static components in the field of view. As examples of systems with static/dynamic transitions, thawing and heating of Intralipid samples were studied by the LSCI approach.
| Original language | English |
|---|---|
| Article number | 155401 |
| Journal | Journal of Physics D: Applied Physics |
| Volume | 51 |
| Issue number | 15 |
| DOIs | |
| Publication status | Published - 26 Mar 2018 |
| MoE publication type | A1 Journal article-refereed |
Funding
This work was supported by the CIMO Fellowships program (21.3.16/TM-16-10089/CIMO Fellowship/WS19), EDUFI Fellowship program (13.10.17/TM-17-10655/EDUFI Fellowship/ WS 19), the Academy of Finland (Grant No. 290596), the Tomsk State University Academic D I Mendeleev Fund Program and the National Research Nuclear University MEPhI’s Academic Excellence Project (Contract No. 02.a03.21.0005). The authors are grateful to A Dombovari, MSc, and Dr G Lorite for their help in the preparation of samples and their useful discussions.
Keywords
- ergodicity
- motion estimation
- optical imaging
- speckle contrast
- speckle pattern