Determination of maize hardness by biospeckle and fuzzy granularity.

In recent years there has been renewed interest in the development of novel grain classification methods that could complement traditional empirical tests. A speckle pattern occurs when a laser beam illuminates an optically rough surface that flickers when the object is active and is called biospeckle. In this work, we use laser biospeckle to classify maize (Zea mays L.) kernel hardness. A series of grains of three types of maize were cut and illuminated by a laser. A series of images were then registered, stored, and processed. These were compared with results obtained by floating test. The laser speckle technique was effective in discriminating the grains based on the presence of floury or vitreous endosperm and could be considered a feasible alternative to traditional floating methods. The results indicate that this methodology can distinguish floury and vitreous grains. Moreover, the assay showed higher discrimination capability than traditional tests. It could be potentially useful for maize classification and to increase the efficiency of processing dry milling corn.

Island analysis of low-activity dynamic speckles.

In this work we present a method to evaluate activity in low dynamic speckle patterns. It consists of binarizing the speckle image and analyzing the displacements and deformations of the resulting speckle grain regions, here called islands. Numerical simulations and controlled experiments were used to study the variations of the island features with the aim of finding a correlation with the activity of the speckle pattern. From the obtained results it was possible to conclude that the developed method can be useful for the analysis of low activity speckle patterns with the advantage of requiring only pairs of frames, thus permitting the assessment of nonstationary processes. In the case of stationary phenomena, so that stacks of frames registers are representative of them, dilute activity images can also be constructed.

Vortex analysis in dynamic speckle images.

Optical vortex analysis has become an important tool in optical metrology. It has been shown to be able to measure small displacements with up to nanometric precision. We analyze optical vortex behavior in dynamic speckle patterns with the boiling phenomenon. We first study translational patterns with boiling and we find the limitations of the optical vortex metrology. Pure boiling patterns are also evaluated and we find a quantitative descriptor for the activity. We also observe that vortices exhibit a Brownian motion in pure boiling patterns. Numerical and experimental results are shown.