SCALE-SPACE FILTER FOR SMOOTHING ELECTRONIC SPECKLE PATTERN INTERFEROMETRY FRINGES

Processing of correlation fringes obtained from electronic speckle pat tern interferometry (ESPI) requires the use of a digital filter to red uce the speckle noise. Even though smoothing algorithms based on the F ourier transform significantly suppress speckle noise, they do not pre serve the image characteristics. The application of a scale-space filt er to reduce speckle noise in ESPI fringes is reported. Results obtain ed using both computer-simulated and experimental fringe patterns are used to test the scale-space filter and they are also compared with th ose obtained by Fourier, convolution, and median filtering. (C) 1996 S ociety of Photo-Optical Instrumentation Engineers.