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We introduce a simple methodology employing digital photography and image processing techniques to do a quantitative study of diffraction. To enhance the range of intensities recorded by a CCD camera without saturation, digital images of the diffraction patterns taken at different exposure times are combined pixel by pixel, and the measured values of the light intensity are fitted to theoretical curves. Diffraction by a single slit, a double slit, and a circular hole were analyzed to obtain quantitative results and demonstrate that the methodology is suitable for student laboratories.

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In this work we implemented dynamic speckle and holographic interferometry techniques to characterize the drying process of solvent-based paint coatings. We propose a simple way to estimate drying time by measuring speckle activity and incrementally fitting experimental data through standard regression algorithms. This allowed us to predict drying time after about 20-30 min of paint application, which is fast compared to usual times required to reach the so-called tack-free state (≈2  h). In turn, we used holographic interferometry to map small thickness variations in the coating surface during drying. We also demonstrate that results obtained from both techniques correlate with each other, which allows us to improve the accuracy of the drying time estimation.

In this work, we measured the biospeckle activity of strawberries (fragaria ⇥ ananassa) with two recently developed algorithms. We observed an important diminution of speckle activity within time periods of 72 h. We tested the methods by analyzing different specimens to check for proper detection of bruised areas or fungal development. The obtained results serve as a starting point to correlate the time evolution of biospeckle activity with aging of fruits, in order to set the basis for development of future standardized fruit quality control procedures.