Light intensity independence during dynamic laser speckle analysis

• Dynamic laser speckle when the illumination is not homogeneous.
• Sample with uniform activity but the illumination is not homogeneous.
• The traditional methods to analyze the biospeckle laser presented reliable results.
• In detail, the methods proposed improve the illumination independence.
• AVD method with a denominator in the traditional method presented the best results.

We explore some different normalizations of current dynamic laser speckle activity measures searching for their performance with respect to the illumination inhomogeneity of the samples. Inertia Moment and Average Value of Differences of the co-occurrence matrix are compared using a paint-drying case study on a uniform sample where attenuation in a portion of the illuminated area is introduced using a neutral density filter. In this way, all environmental conditions being equal but non-uniform illumination permits the comparison on a better approximation to objectivity. The results presented show that it is possible to mitigate the effects of the illumination in the activities measured by the dynamic laser speckle.