Experimental Research On Dynamic Range-Gated Laser Imaging

Range-gated imaging can obtain both intensity image and three-dimensional range image by the range-gated slices, which can effectively overcome the backscattering. It is one of the few focal plane imaging technologies that has engineering application potential. Dynamic imaging is a major direction of development direction of laser active imaging that has great importance in aerospace and industrial areas. This thesis focuses on the adaptability of range-gated imaging system to dynamic imaging.First, we proposed an imaging scheme based on range-gated technology and GPS. Adding GPS to the range-gated laser imaging system, we built the dynamic range-gated laser imaging systerm. Analyzing the work of GPS and dynamic range-gated model, we obtained the relations between various dynamic parameters, and analyzed the range errors caused by the GPS.Second, We analyzed the causes for dynamical distortion, then proposed a dynamic imaging distortion evaluation method based on Zernike moment invariants and evaluated the simulated dynamic images. Through the simulation, when velocity is 10m/s and imaging frame rate is greater than 4Hz, the simulated image's distortion is small. When the imaging frame rate is 20Hz, velocity is lower than 60m/s, the simulated image's distortion is small.Third, we built a dynamic range-gated laser imaging system. Dynamic laser imaging system consists of laser emitting system, laser receiving system, controlling center and data processing system, synchronous control systems and GPS. In this thesis, we analyzed the system's critical modulus and dynamic imaging of protective imaging equipment in detail.Finally, we did dynamic range-gated laser imaging experiments. We evaluated the distortion of dynamic images and analyzed the system's dynamic adaptability. We conducted dynamic experiments and processed the slices in order to get the intensity image and 3D range images. Subsequently, we evaluated the images. The distortion increases with the velocity larger, the speed of 20km/h case, when the imaging frame rate is greater than 5Hz, the distortion is small enough to meet the requirements of dynamic imaging.