title: The effects of particle size on contrast improvement by polarization discrimination for underwater targets.
abstract: Luminous flux was measured from an underwater target illuminated by circularly polarized lamp. Backscatter was measured with and without a circular analyzer on the telephotometer. Turbidity of the water was controlled by adding polystyrene spheres of relative refractive index m = 1.20. Contrasts were determined as a function of particle diameter and concentration for spheres ranging from 0.126 micro to 1.099 micro and for three size distributions from 6 micro to 100 micro. A ratio comparison of the contrasts showed a definite improvement for scatterers of diameters > 1 micro. Contrast degraded for CP illuminated scattering from spheres in the 1-100-micro diam range. Considering the ocean's scatterer-size distributions, circular polarization will probably most improve contrast in the vertical region from the lower euphotic zone to a few meters above bottom.
authors.forename: G D
authors.initials: GD
authors.lastname: Gilbert