Analysis of surface changes of burning nanopowders using digital processing of laser monitor images

Abstract

An imaging laser projection system, a laser monitor, is applied for real-time monitoring of the surface of nanopowders during high-temperature combustion. The mirror-based scheme of the laser monitor is used in the experiments to increase the range of observation. For the analysis of surface changes during combustion, the correlation coefficient together with average brightness of the images of laser monitor obtained by digital processing are proposed to use. The results of calculating the correlation coefficient demonstrate compliance with the change in the intensity of the images of the laser monitor during the combustion and visual observation of the combustion process. The distortions introduced by the instability of the brightness amplifier into the measurement results are estimated. When observing a static test object, the variation of correlation coefficient is three orders of magnitude less than fluctuation in the correlation coefficient during combustion, the variation of average image brightness is less than 5%. The obtained results indicate the possibility of the usage of the correlation coefficient and average brightness of the images as informative parameters in the analysis of surface changes of burning nanopowders in studies using laser monitors with both conventional and mirror-based schemes.