1. Beihang University, School of Instrumentation Science and Opto-electronics Engineering, Xueyuan Road No. 37, Beijing 100191, China
2. United States Department of Agriculture, Agricultural Research Service, Crop Production Systems Research Unit, Experiment Station Road, Stoneville, Mississippi 38776, United States
3. Beijing Institute of Space Mechanics and Electricity, Youyi Road No. 104, Beijing 100094, China