Two methods that exploit the capabilities of optical pattern recognition techniques are investigated for characterizing spherical and nonspherical particulates. Experimental data are presented demonstrating the ability of the circular harmonic filter and the computer-generated holographic wedge detector to distinguish three classes of particles. The three particle types represented include opaque spherical particles, fibrous particles and brass flakes. A simple figure-of-merit capable of discriminating between the three particle types is defined using the outputs from the computer-generated holographic wedge detector. The figure-ofmerit is independent of laser intensity and invariant with particle scale and rotation changes.
Martin S. Marshall,
"Particle recognition using circular harmonic filters and a computer-generated holographic wedge detector," Optical Engineering 35(3), (1 March 1996). http://dx.doi.org/10.1117/1.600662