Array Imaging Three Dimensional Ladar

Information capture technology is an endless exploration. The Array Imaging Three-Dimensional Ladar (AI3DL) technique, as one of most attractive information capture technology, has a capability to provide precision and rapid capture of vast 3D information. AI3DL technique is highly sought in a wide variety of applications in military, national economic construction, agricultural ecology, etc. However, there are still many problems desiderate to be solved to meet the strict requirements of application. In the view of theoretical research and practical application, the noise model and the ways to improve 3D resolution performance are studied thoroughly in this dissertation.The main researched contents and their achievement are as follows:On basis of the prototypical AI3DL, the noises factors and system error factors from each detection process are analyzed to establish noise model of AI3DL. The noise model is used to analyze the range resolution of AI3DL. It is found that the energy received by the detectors limits the resolution. The research results indicate ways to improve the performance of AI3DL.One of the solutions is to enhance the efficiency of the optics system. Evaluation function of the illumination effect to range resolution is proposed. It is found that uniform illumination can reduce the total relative error by 25% compare to Gaussian irradiance distribution of the same transmit energy. Beam shaping method of uniform illumination for laser diodes stack is studied. A beam shaping method by superposition of tilted fundamental mode Gaussian beams to form a nearly uniform illumination is proposed. The analytical formula for average intensity of the multi-tilted Gaussian beams (MTGB) propagating is derived and used to study the uniform properties of the beam profile by the Fourier analysis method. It is found that the MTGB maintain the flat-topped shape as it propagates. And the uniform properties of the MTGB are closely related to the parameters of fundamental beams and superposition. Both analytical formula derivation and the numerical examples are illustrated. The optical design is proposed in detail. The results show uniformity better than 80% and a shaping efficiency about 75% on the condition of presently LD stack rigging error. The uniform illumination method for LD stack based on light pipe is proposed, simulation results showed 80% uniformity and 73% shaping efficiency. Another uniform illumination method for LD stack based on fly's eyes is proposed and proved in ASAP software. The influence of the receiver optics including imaging lens and relay lens to resolution is analyzed. The structure and parameters of high efficiency imaging lens and relays lens are presented. A low cost optical fiber coupling system used for fiber accuracy calibration is developed.A novel pulse shape free AI3DL is proposed and its experiment system is introduced.The effect of optical transfer function to range resolution and spatial resolution in range images are studied. The edge response is used to caculated Modulation Transfer Function (MTF) of the AI3DL system in outdoor test. The range resolution degradation by MTF influence is proved by the experiment. It is find that the present system MTF is about 251p/mm and these make proper pixels binning an acceptable approach to improve the range solution without reduce the spatical resolution in range image.The range resolution is evaluated by measuring the several repeatable objects. The experiment shows that the range resolution is affected by the object charactircs and object range. At a gated range of 600m to 1000m, the range solution is 1.6m to 13.5m. It is another proof to the noise model of AI3DL.