Focal Plane Spectroscopic Technique Of Optical Fiber Array For Hyperspectral Imaging Lidar

The simultaneous acquisition of the elevation and hyperspectral information of a target is a future research area in remote sensing surveying and mapping technology.Among the current main technical methods,lidar can acquire the elevation information of the targets,and passive imaging instruments can obtain hyperspectral information.However,neither of these methods can achieve the simultaneous acquisition of the co-located elevation and spectral information.However,in the hyperspectral imaging lidar system,the hyperspectral information and elevation information of ground objects come from the same footprint point,and they can be combined to achieve accurate detection of ground object information.In view of the advantages and disadvantages of the current active and passive remote sensing detection technology.A novel technique is proposed by using a optical fiber array equipped at the focal plane of the receiving telescope.A hyperspectral imaging lidar system adopting this technique is successfully built for detection a target at a distance of 500 meters within the spectral band from 500nm to 800nm.Continual improvement of the optical-mechanical integration of lidar system can further improve the detection capability of the system.The design of the hyperspectral imaging lidar receiving system,the scanning mode of the system,the calibration of the system and the preliminary outdoor experiment are the emphases of the thesis.The research work of this paper includes the following aspects:1.The significance of application and advantages of the hyperspectral imaging lidar are reviewed.Aiming at the technical difficulties of the current hyperspectral lidar,an airborne hyperspectral lidar system was designed based on the optical fiber array focal plane spectroscopic technology.It realizes the multi-channel splitting and efficient coupling of the wide spectrum echo signal.The design fully shows the detection advantage of hyperspectral lidar.2.Compared with the traditional lidar,the hyperspectral imaging lidar system built in this research is a brand-new technology for Earth surface observation.Before the spectral information measured by the hyperspectral imaging lidar system is applied to the task of ground object classification,the spectral calibration of the system is completed in the laboratory,and the central wavelength and bandwidth of each channel of the system are preliminarily determined.At the same time,the theoretical method to complete the radiation calibration of the system is given.In the outdoor experiment,a method of radiation calibration using standard whiteboard is presented.3.Scanning mode is also an important design for a hyperspectral imaging lidar.This thesis mainly introduces the three scanning mode,such as polyhedral rotating mirror scanning,vibrating mirror scanning and conical scanning,which are widely used at present for lidar scanning.The trajectories of various scanning modes are deduced theoretically first,and the relationship between scanning mode and laser scanning trajectory is then obtained based on the actual flight path of airborne platform.Taking tetrahedral rotating mirror as an example,the actual scanning trajectory of the rotating mirror combined with the flight track parameters is simulated and analyzed.Finally,a conical scanning method is chosen for our hyperspectral imaging lidar system.4.The outdoor static performance test of the hyperspectral imaging lidar has been completed for detecting a target at a distance of 500m which is very important preparation before the airborne flight of the hyperspectral imaging lidar.The ground experiment results show the detection ability of this lidar system meets the designed requirements.Some problems are also found during the performance test,and the detailed solution and improvement is proposed eventually.