High-speed structured planar laser illumination for contrast improvement of two-phase flow images

摘要

A high-speed method to remove blurring effects caused by multiple scattering in planar laser images of two-nphase flows is demonstrated. The technique is based on structured illumination and is for the first time tonour knowledge applied on a dynamic medium. As structured illumination requires three successive imagesnto be recorded and to freeze the flow motion in time, a high-speed laser and imaging system is employed. Wenshow that by using a time delay of 55 u0001s between the images a single-shot representation of a dilute flow ofnwater droplets can be achieved. By having an additional inner stream with known structure and composi-ntion, the efficiency of the method is quantitatively evaluated, showing an increase from 58% to 93% in imagencontrast. Such an improvement allows more accurate analysis and interpretation of scattering two-phasenflow images. © 2008 Optical Society of America