Quality test protocol to dynamic laser speckle analysis

Abstract

Biospeckle (BSL) is a phenomenon that develops when a dynamic process occurs under laser illumination in a material containing considerable information on biological and non-biological activity. Analysis of such data has been a challenge because of complex interaction between light and material, and therefore, of high sensitivity of the BSL and variability of biological material. This study was aimed at improving the robustness of BSL techniques and thus reducing its subjectivity and dependence on human expertise. The work presents a protocol that aids in a quality test of three key features of the speckle patterns, particularly those related to saturation, under-exposure, homogeneity and contrast of the grains. The quality test was carried out with data from a maize seed and a paint drying under biospeckle laser monitoring, where it was possible to identify some problems in the images related to the tested features. The results establish the feasibility of the quality test control, which form the early steps of the biospeckle laser analysis, and serves in helping the judgment of the setup.