Because light is scattered and absorbed by seawater, the images obtained underwater are always blurry after transmitted through a certain distance. The point spread function (PSF) and modulation transfer function (MTF) are important properties of seawater to predict underwater light propagation and underwater image quality. We describe the laboratory facilities to measure the PSF and MTF of water body by the image transmission method and the restoration methods of underwater blurred images. The measured results are given and compared with the theories. The blurred images of a bar target transmitted through different water paths are restored with the measured MTF using a Wiener filter.

This note reports a new type of incoherent pulse laser Doppler lidar velocimeter with iodine molecular filter as a frequency discriminator. Its transmitter subsystem applies a Nd: YAG pulse laser which is injected with a single longitudinal-mode diode pumped continuous seeder laser. The field experiment proved that this velocimeter measurement results are consistent with those measured by photoelectric velocimeter. Measurements of eight different velocities show that the standard deviation is 0.56m/s, the range resolution is 3.75m.

The theory and experiments for a multichannel optical system for pseudocolor encoding of images are presented. Spatial-frequency pseudocolor encoding is accomplished by spatial filtering different-colored spectra in different channels. Density pseudocolor encoding is accomplished by the incoherent addition of three primary color images: a contrast-reversal image in one color, a positive image in the second color, and a contrast half-reversal image in the third color. This is a simple, real-rime'technique. It has no resolution loss that is due to the use of gratings or halftone screens, and the optical system does not require Fourier-transform lenses with large relative apertures.

This paper briefly discusses the mobile ground-based incoherent Doppler wind lidar system, with iodine filters as receiving frequency discriminators, developed by the Ocean Remote Sensing Laboratory, Ocean University of Qingdao, China. The presented result of wind profiles in October and November 2000, retrieved from the combined Mie and Rayleigh backscattering, is the first report to our knowledge of wind measurements in the troposphere by such a system, where the required independent measurement of aerosol-scattering ratio can also be performed. A second iodine vapor filter was used to lock the laser to absolute frequency reference for both wind and aerosol-scattering ratio measurements. Intercomparison experiments of the lidar wind profile measurements were performed with pilot balloons. Results showed that the standard deviation of wind speed and wind direction, for the 2-4 km altitude range, were 0.985m/s and 17.9

The East China Sea is a typical case 2 water environment, where concentrations of phytoplankton pigments, suspended matter, and chromophoric dissolved organic matter (CDOM) are all higher than those in the open oceans, because of the discharge from the Yangtze River and the Yellow River. By using a hyperspectral semianalytical model, we simulated a set of remote-sensing reflectance tbr a variety of chlorophyll, suspended matter, and CDOM concentrations. From this simulated data set, a new algorithm for the retrieval of chlorophyll concentration from remote-sensing reflectance is proposed. For this method, we took into account the 682-nm spectral channel in addition to the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) channels. When this algorithm was applied to a field data set, the chlorophyll concentrations retrieved through the new algorithm were consistent with field measurements to within a small error of 18%, in contrast with that of 147% between the SeaWiFS ocean chlorophyll 2 algorithm and the in situ observation.