Laser Polarization and Reflectance Characterization of Selected Target and Background Material

摘要

This paper describes the relative polarization and reflectance characterization of background and selected target items to demonstrate the differences material type and source wavelength have on these measurements. The advanced reflectance and polarization instrument (ARPI) was modified to allow three lasers with different wavelengths to be used. This allowed for similar spot size, location, and angles to be used to collect the measurements. ARPI was used to collect polarized and cross-polarized returns from the polarized laser source at an incident angle of 0, 5, 10, and 20 degrees. These measurements were used to calculate the relative percent polarization and percent reflectance. Analysis of the measured relative polarization and reflectance consists of single wavelength and multi-wavelength comparisons with man-made and background items. A direct comparison is made between natural and man-made materials and different wavelengths of light. This careful comparison of differences between wavelengths will demonstrate which of the wavelengths produces the best and most consistent separation between background and man-made items. Our preliminary analysis shows that most man-made items give different polarization and reflectance returns than background items. Also, the analysis shows nominal variability between the three different wavelengths for background items and man-made items.