Studies On The Dual-channel Dynamic Three-Dimensional Laser Radar Imaging System

As a new mean of detection, three-dimensional imaging laser radar has been a research focus during these years. Compared with other kinds of laser radar, it can quickly get the distance images of high precision without scanning devices. As a result, the three-dimensional imaging laser radar can be widely used in data collection of 3D geological information, features capture of forests and town Planning.The development of three-dimensional imaging laser radar is introduced in this paper. Based on the disadvantages of current laser radar, we proposed a new design of dual imaging channel. After registration of pixel, dual-channel imaging system, overcoming the shortcomings of single-channel imaging system which can only get the distance images of static objects, can get the gray images of different gain modulation of the target at the same time. After that, the distance images can be obtained by these two images of constant gain and linear modulated gain. Thus the dual-channel imaging system can be used to get dynamic images.In this paper we describe the construction of dual-channel imaging system in detail. The method of affine transformation is employed to achieve registration between two channels. Besides, we design the control circuit of imaging system, including the signal generator circuit, gated circuits, linear gain modulation circuit, temperature control circuit and power circuit. The impact of the quality of control signals on the range accuracy is analyzed, and the experimental results show that the performance of the circuits are so good that they have little impaction on the ranging accuracy. The static ranging and dynamic simulation was developed in the outdoors. The results show that the dual-channel laser radar can be used on the plane by increasing the energy of the semiconductor laser and receiver efficiency of imaging system.Based on the principle of laser radar, the ranging accuracy under the point spread function limited circumstances is firstly analyzed. Simulation is carried out to analyze the affection of the reflectivity, the actual distance and some other factors on the ranging results of fast-distance-varying region. For the measurement error is caused by different reasons in different regions, a method which uses sectioned restoration on obtained gray images is presented. Simulation results show that RMSE of distance map obtained with this method is decreased compared with global restoration. Finally, the restoration results of imaging radar pictures are demonstrated to verify the effectiveness of this method.At the last part of the paper, the research results are summarized and the next steps of the entire project are discussed.