Quantitative single-exposure laser speckle contrast imaging

Abstract

Laser speckle contrast imaging (LSCI) is a well-established blood flow imaging technique, through the computed whole field contrast map. Though LSCI offers high spatial and temporal resolution, accurate quantification of blood flow remains a challenge. In this paper, we demonstrate a single exposure system, introducing a modified velocity computing approach incorporating the effects of scattering events and other experimental parameters to result in a relatively inexpensive LSCI system with near real time results. Parameters like vessel dimension and concentration of scattering centers are cumulatively represented by defining the number of scattering events in the region of interest (ROI). The number of scattering events is considered along with the decorrelation time in deducing flow velocity. We present a modified equation for velocity computation incorporating the effects of scattering centers. This work attempts to bring consistency in flow velocity calculation across different samples to achieve a robust single exposure LSCI system. The LSCI setup was calibrated based on a system dependent constant, which was found to be a linear function of flow velocity, to predict velocity quantitatively. We present the results of the developed system on standard micron-sized flow channels.