Light intensity dependence during dynamic laser speckle measurements

Dynamic laser speckle is a sensitive optical phenomenon used to monitor activity in biological and non-biological material. The activity in the speckle patterns is a result of many phenomena which has its complexity amplified in biological samples. The interaction of the light with biological material is a challenge to users, and one complex question is the influence of the level of the laser beam in the quality of the information brought to observers. This work evaluated the influence of laser intensity in coffee seeds and roots, and in a non-biological phenomenon, the paint-drying. The laser intensity was varied directly in the laser set or by means of a semi-filtering. Images were analysed by means of graphical and numerical processing and the results showed that the quantity of light influenced the final information. In addition, a different level of illumination on a same surface conducted to a distinct outcome using the traditional methods. Therefore, some adjustments of the image processing were proposed presenting enhancement of the final outcome, as well as a discussion about the quantity of the light over the samples were carried out in order to avoid misjudgements.