Computer simulations and experimental data are presented for various ternary phase-amplitude filters used to size opaque spherical particles. We first report on nearly unlimited spatial frequency ternary phase-amplitude filters derived directly from the classical matched filter for opaque spherical particles in the size range of 100 to 400 µm. Next we investigate the increasing influence of the cutoff frequency on the optical correlator as the particles become smaller. Using limited-order ternary phase-amplitude filters, we report on sizing opaque spherical particles in the size ranges of 100 to 400, 15 to 100, and 5 to 25 µm.
© 1992 Optical Society of America
Martin S. Marshall and Robert E. Benner, "Spherical particle sizing by optical correlation using ternary phase-amplitude filters," Appl. Opt. 31, 644-651 (1992)