激光雷达成像特征分析及应用研究

发布时间：2018-04-15 06:21

本文选题：激光雷达 + 成像系统仿真　；参考：《西安电子科技大学》2016年博士论文

【摘要】：激光雷达成像系统由于具有复杂环境适应性强、抗干扰能力强、获取信息量大等特点,被广泛用于战场侦察、预警和打击等国防领域以及机动车辆伺服、人工视觉、地形测绘等民生领域,在现代战争和日常生活中都具有不可或缺的地位。激光雷达成像系统的特征预测和性能评估的研究是激光雷达成像系统设计、特征感知与算法研究、系统方案论证等应用的必不可少的内容。基于数字仿真的激光雷达成像特征预测与应用技术具有可靠、无破坏性、可多次重复、不受气象条件和场景空域限制、控制灵活等特点,能够降低研发风险、缩短研制周期、节约研究与试验经费,具有重要意义。本文以实现激光雷达成像系统建模仿真的特征预测和性能评估为研究目标,针对激光雷达成像仿真链路、链路中的高性能场景建模、高置信度场景建模、成像系统建模与评估等关键问题进行了研究,开展的具体工作如下：第一部分研究了基于系统成像原理的激光雷达仿真链路。为了满足激光雷达成像仿真系统通用性和复杂度扩展性的需求,详细分析了激光雷达成像系统的基本理论,研究了探测原理和成像模式；其次,以激光雷达成像系统的基本理论为指导,提出了通用的、系统化的“发射-目标-背景-大气-成像-点云重构”激光雷达成像系统仿真链路,并对链路中的通用子模块进行了详细分析,建立了通用的激光雷达成像仿真模型。第二部分研究了场景辐射特性高性能计算方法。为了解决传统激光雷达反射场景计算方法动态性差、计算复杂、无法表现激光相干性等问题,分析了目标和背景的反射特性,研究了激光的空间传输特性,通过改进辐射传输计算、添加散斑模型等手段,建立了场景辐射特性模型,结合GPU并行处理机制,提出了激光辐射场景的高性能计算方法,实现了激光雷达成像系统入瞳能量分布的高效计算,并与实际结果进行了比对分析,验证了三维散斑模型及仿真方法的可信性和可行性。第三部分研究了场景辐射特性置信度改进方法。为了提高激光辐射场景的精确度,研究了光线跟踪和计算机视觉渲染的基本原理,分析了光线跟踪技术应用在激光雷达系统成像模型的可行性。为了解决激光雷达仿真环节中无法准确描述多次反射、半透射及遮蔽等过程的问题,对基本光照模型进行了改造,提出了基于光线跟踪算法的激光辐射场景的方法,实现了复杂目标的精确模拟计算,有效弥补了传统方法的缺陷。为了解决激光雷达仿真环节中大气传输影响的准确度欠缺的问题,提出了利用指数韦布尔的湍流模型计算激光辐射场景大气湍流干扰的方法,建立了综合大气湍流传输的激光雷达成像物理模型,实现了大气传输效应对成像质量影响的定量计算,计算结果表明湍流导致能量弥散,引起探测虚警,影响成像能力。第四部分研究了激光雷达成像系统建模及性能评估方法。基于三维能量分布计算的结果,详细分析了GMAPD探测原理,建立了基于GMAPD探测的激光雷达系统成像模型。为了载体平台数据匹配精度不高、成像模型通用性差的问题,建立了基于实际数据的点云配准模型,并结合本地坐标转换模型和世界坐标转换模型,实现了载体平台下激光雷达数据的三维点云重建模拟,通过对机载平台下基于GMAPD探测的激光雷达系统的成像仿真,验证了方法的可行性和可信性。为了解决传统方法中环境噪声辐射对系统性能干扰影响的计算结果误差过大的问题,提出了耦合探测波段的环境噪声辐射计算方法,修正了探测像元的入射环境辐射能量结果,提高了环境干扰模型的计算精度。利用复合仿真模型,以异常比和失落比为系统性能评估指标,分别对不同的大气传输、环境噪声强度、发射激光参数和系统暗电流强度条件下系统性能指标进行了计算,实现了多种工作环境和系统参数下激光雷达系统的性能评估。
[Abstract]:Laser radar imaging system has strong adaptability to the complicated environment, strong anti-interference ability, to obtain large amount of information, is widely used in the field of battlefield reconnaissance, warning and Combat Defense and servo motor vehicles, artificial vision, topography and other livelihood areas, has an indispensable role in the modern war and the characteristics of daily life. Prediction and performance evaluation of laser radar imaging system is the design of laser radar imaging system, characteristics of perception and algorithm, the system project applications such as the essential content. Laser radar imaging features and application technology of digital simulation based on reliable, non-invasive, repeatable, not affected by weather conditions and scene airspace restrictions the characteristics, flexible control, can reduce the risk of research and development, shorten the development cycle, saving research and test cost, is of great significance. In this paper, in order to achieve Feature prediction and performance evaluation of laser radar imaging system simulation modeling as the research target, the laser radar imaging simulation link, high performance link in scene modeling, scene modeling with high confidence, the key problem of imaging system modeling and evaluation are studied, the specific work is as follows: the first part of the laser radar simulation link system based on the principle of imaging. In order to meet the demands of scalability of laser radar imaging simulation system versatility and complexity, a detailed analysis of the basic theory of laser radar imaging system, the detection principle and imaging mode; secondly, based on the basic theory of laser radar imaging system as a guide, put forward the general and systematic "emission - target - background - atmosphere - - point cloud reconstruction imaging laser radar imaging system and the simulation of the link, link the general module to conduct a detailed analysis , established a general simulation model of laser radar imaging. The second part discusses the high performance computing method of radiation characteristics of scene. In order to solve the traditional laser radar scene dynamic calculation method, the calculation is complex, not performing laser coherence problems, analysis of the reflection characteristic of target and background, to study the spatial characteristics of the laser beam propagation through. Improvement of radiative transfer calculations, add speckle model, established the radiation characteristics of the scene model, combined with the GPU parallel processing mechanism, puts forward the calculation method of high performance laser radiation scene, realizes the efficient computation of laser radar imaging system of the pupil energy distribution, and compared with the actual results, verify the credibility and feasibility three dimensional speckle model and simulation method. The third part studies the radiation characteristics of the scene confidence improvement method. In order to improve the precision of laser radiation scene Indeed, on the basic principle of ray tracing and rendering of computer vision, the paper analyzes the feasibility of application of ray tracing technology in laser radar imaging model. In order to solve the multiple reflection cannot accurately describe the laser radar simulation process, and the process of the semi transmissive shielding problem, the basic illumination model was improved, and puts forward the method of laser radiation scene ray tracing algorithm based on accurate calculation simulation of complex targets, effectively compensate for the shortcomings of the traditional methods. In order to solve the lack of accuracy of atmospheric transmission of laser radar simulation process influencing the problem, provide a method to calculate the laser radiation scene of atmospheric turbulence disturbance using turbulence model exponential Weibull, establish the laser radar imaging model of integrated turbulence, realized the quantitative effect of atmospheric transmission effect on imaging quality calculation, The calculation results show that turbulence causes energy dispersion, caused by false alarm, affect the imaging ability. The fourth part studies the evaluation methods of modeling and performance of laser radar imaging system. The three-dimensional energy distribution based on the computed results, a detailed analysis of the GMAPD detection principle, a laser radar imaging system based on GMAPD model. In order to detect carrier platform data matching accuracy is not high, the imaging model of the poor generality, the establishment of the actual data of point cloud registration model based on combining local coordinate transformation model and the world coordinate transformation model, and the carrier flat 3D point laser radar data sets under the cloud reconstruction simulation, based on the simulation of imaging laser radar system based on detection of airborne GMAPD the platform to verify the feasibility and credibility method. In order to solve the calculation results of environmental noise in the traditional method of radiation effects on the performance of interference system The problem of error, puts forward the calculation method of noise coupling detection band radiation, fixed pixel detection results of incident radiation energy environment, improves the precision of environmental disturbance model. Using the composite simulation model, the abnormal ratio and loss ratio for the system performance evaluation index, respectively on the atmospheric transmission of environmental noise strength, performance index system laser parameters and system under the condition of dark current intensity was calculated, performance evaluation to achieve a variety of working conditions and system parameters of laser radar system.

【学位授予单位】：西安电子科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN957.52

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