Fast detection method of calibrator spaceborne sun glint based on FPGA

Abstract

Sun glint is a serious obstacle to passive optical remote sensing images. As is the specular reflection of sunlight from the facets of the water surface, sun glint has great linear polarization characteristics, and it is usually suppressed by adding polarizers. Therefore, a spaceborne sun glint polarization parameter measurement system is developed to calculate the on-orbit sun glint parameters in real time. Firstly, we analyzed the polarizing radiation distribution model of sun glint and developed a real time detection system for polarization angle of sun glint according to the principle of spaceborne polarization imager. The system is using Xilinx V5 FPGA as the on-the-satellite processing platform, and we use high-level synthesis (HLS) tools for algorithm hardware description development. By using dataflow, pipeline and other optimization methods in HLS, we greatly reducing computing time and reducing the FPGA resource use. Finally, we use it to calculate the sun glint polarization angle through a three-channel data with a granularity of 25×25 in 670nm, the simulation results show that under the 100M clock, 54% of the slice and DSP48 FPGA resources are consumed, and the sun glint polarization angle can be calculated in 8ms time, which meets the design requirements of rapid sun glint detection.