3D scanning coherent lidar demonstration using frequency modulated continuous wave

Abstract

There are lots of requirements of 3D terrain information in the field of traffic and forest investigation. In this paper we propose a coherent lidar system that produces 3D information of target by use of circularly scanning system. We use the frequency modulated continuous laser wave as optical source. The frequency information from the targets can be demodulated by the FFT algorithm to get the real distance information and generating a point cloud. The method has advantage of background noise resistance over traditional direct detection system. The demonstration system not only acquire the distance information of scanned target. It also measures the dynamic information such as speed of moving target. In our work, we measure the speed of swaying leaves of a tree within gentle breeze and the measurements are in line with the experimental environment at that time. Furthermore, a complicated demonstration system including four laser sources will be designed. More laser footprints can enlarge the scanning area at per second and mitigate modulation and demodulation stress of system, which acquires more detailed information.