Investigations of the Polarization of Light Reflected by Natural Surfaces

摘要

The polarization features of light reflected by soil, desert sand, white sand and water under different conditions of illumination with natural (unpolarized) and polarized light were investigated in three narrow spectral intervals (band width approximately 150A) centered on wavelengths 3975, 5000 and 6050A. A simple 'rotating-analyzer' type photoelectric reflectometer was used in the measurements. The data was acquired in computer compatible format to facilitate Fourier analysis of the photosignal. The degree of polarization and relative intensity variations were determined from a knowledge of the Fourier coefficients. The polarization of light reflected by soil, desert sand and white sand exhibits pronounced wavelength dependence. There is overall similarity in the behavior of soil and desert sand. White sand shows a strong tendency to behave like an ideal diffuser (Lambert surface). The hypothesis of scattering of light by an 'optically rough, locally smooth' surface has to be invoked to explain the reflection characteristics of an apparently smooth surface of water. (Author)