Alternative protocols on dynamic speckle laser analysis

Abstract

Biospeckle or dynamic laser speckle is a phenomenon developed when a dynamic process occurs in a material under laser illumination. This phenomenon contains considerable information related to both biological and non-biological activity of the material under study. As a non-invasive, non-destructive and low cost technique, biospeckle laser (BSL) has been an outstanding tool for monitoring biological properties. Thus, its application in optical instrumentation has grown over the years, especially in the areas of biology, medicine and agriculture. High sensitivity of biospeckle laser (BSL) technique and variability of biological material combined with the large number of variables involved in speckle pattern formation have brought great challenges to the search for safer, more robust analysis techniques. Therefore, this study aimed to develop and refine methodologies for the BSL analysis and tested alternative protocols for the prime analysis. Particularly, we present a protocol to obtain requirements before the main analysis, in an attempt to eliminate image quality based on subjectivism or research experience. This protocol was based on the creation of requirements to achieve the best speckle patterns such as evaluating the saturation, the homogeneity and the contrast of the grains. The alternative protocol offered a testing approach before the main experiment to increase the certainty to get image and data in an accepted quality, avoiding the loose of time and samples in analysis of a row of a questionable data. The tests were performed in well-known BSL data and presented as a feasible step before the main experiments.