Nonlinear diffusion filtering of images obtained by planar laser-induced fluorescence spectroscopy

The application of nonlinear anisotropic diffusion filtering to reduce nois e and enhance contours in images obtained by two-dimensional planar laser-i nduced fluorescence (PLIF) spectroscopy is presented. In this process the d iffusion coefficient is locally adapted, becoming negligible as object boun daries are approached. Noise is efficiently removed, and object contours ar e strongly enhanced. The technique is demonstrated with PLIF images obtaine d from the OH radical recorded in turbulent flames. We show that nonlinear diffusion is suitable as a preprocessing step, before image segmentation be comes possible, and we demonstrate how the technique is applied for the qua ntitative extraction of dame reaction boundaries from PLIF data. (C) 2000 O ptical Society of America [S0740-3232(00)03612-7] OCIS codes: 100.2000, 300 .2530, 280.1740.