A single-pulse imaging laser projection system (laser monitor) is proposed for real-time monitoring high-speed processes shielded by the intensive background lighting. The brightness temperature of the lighting can reach thousands or even tens of thousands of degrees, which makes it difficult to observe the processes with the naked eye. The estimates of limiting temperatures show that the use of the proposed instrument allows to view the objects when the equivalent brightness temperature of the background lighting is up to 45 000 K. The results of visualization of some bright objects and processes using high-speed copper bromide vapor laser monitor are presented.
This paper presents the results of real-time monitoring of air combustion of aluminum nanopowder and its mixtures with aluminum micropowder and iron oxide III. An optical system with a brightness amplifier was used along with visual monitoring to characterize the reflectivity of the sample surface. The reflectivity was analyzed after registering by a photodiode the intensity of radiation reflected from the surface and then amplified by the brightness amplifier at 510.6- and 578.2-nm wavelengths. Analysis of the images obtained with a high-speed camera and the photodiode output oscillograms showed that the intensity of the brightness amplifier output corresponds to the main stages of the combustion process, including the beginning of combustion, spreading of the heat wave and rise of the second combustion wave. The proposed technique is adequate for real-time monitoring of the combustion process with temperatures of 2200 °C-2400 °C, which is accompanied by intensive lighting.
Testing the method of speckle pattern processing based on the digital image correlation is carried out in the current work. Three the most widely used formulas of the correlation coefficient are tested. To determine the accuracy of the speckle pattern processing, test speckle patterns with known displacement are used. The optimal size of a speckle pattern template used for determination of correlation and corresponding the speckle pattern displacement is also considered in the work.