Visualization of Hydrogen Flame by Differential Imaging of OH Emission

Abstract

Hydrogen flame was visualized by imaging at 309 nm, which coincides with the principal peak in the emission spectrum of the OH radical. An image intensifier was used to amplify the image. The background image at 337 nm was obtained simultaneously, and the spatial region corresponding to the flame image was extracted. A combination of (1) binary digitization using a threshold level and (2) Gaussian blur was used to remove the spurious spots which resulted from the grainy images obtained by the image intensifier. The use of differential imaging allowed imaging of hydrogen flame in outdoor, daylight conditions, up to a distance of 30 m.