A new method is proposed for simultaneously measuring the size and retroreflection of glass microspheres, and a system of statistical characteristics is introduced for monitoring optical quality. Measurements are carried out for various size fractions in the interval 100−700 µm. A criterion for estimating the quality of the microspheres in terms of the throughput power is proposed that makes it possible to expand the possibilities of the technique, based on an analysis of their images. It is shown that it is possible to take into account the influence of defects of the microspheres on the retroreflective properties of the coatings.
L. A. Ivanov, N. N. Kiselev, V. A. Slugin, D. V. Kiesewetter, and V. I. Malyugin, "Measuring the retroreflection from glass microspheres and predicting the quality of retroreflective coatings," J. Opt. Technol. 73, 29-33 (2006)