A novel highly efficient algorithm for laser speckle imaging

Laser speckle imaging (LSI) is a non-invasive optical imaging technique able to provide wide-field two-dimensional maps of blood flow. The observer can either define different sizes for the region of interest to reduce the spatial variability or different time duration over which the blood flow values are averaged to decrease temporal variability. In this paper, we present a new algorithm for integrated speckle contrast, which accounts not only for temporal integration but for spatial integration as well, using a low time – consuming efficient algorithm. As a result, we find that an efficiency factor should be introduced to the measured speckle contrast to properly normalize and eliminate background noise; otherwise, the measured contrast is affected. Furthermore, we demonstrate its feasibility for relative flow speed assessing.