<title>Experimental determination and modeling of volumetric optical properties</title>

Abstract

Knowledge of the spatial and temporal variability of the optical properties of a particular water mass has important applications in biological and physical oceanography. As a step towards acquiring the capability to measure the variation in inherent water properties in three dimensions, an underwater optical imaging technique based on the volumetric reconstruction of serially acquired image planes was used to experimentally determine the spatial microstructure of phytoplankton distributions. Volume fluorescence, (beta) (phi) (90 degree(s), 450 nm, 685 nm), and scattering, (beta) (90 degree(s), 450 nm), images were acquired and processed for three-dimensional distribution analysis. In support of the experimental imaging equipment design and to verify applicability of the technique over a wide range of oceanic parameters, computer modeling of this serial sectioning technique was accomplished. Image plane intensity calculations implemented in the model accounted for wavelength specific differential variations in attenuation over the light propagation paths. Modeling and experimental results indicate that the underwater optical serial sectioning technique is practical for in-situ determination of cubic meter volume fluorescence and scattering functions of phytoplankton distributions with chlorophyll (alpha) concentrations as low as 0.1 mg Chl (alpha) /m3.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.