【作者】 赵龙；

【导师】 颜云辉；

【作者基本信息】 东北大学 ， 机械设计及理论， 2017， 硕士

【摘要】 高温金属件的测量环境及其复杂,使传统的接触式测量方法失效,而基于结构光的非接触式测量方法是解决上述难题的一个重要方向。该测量技术存在三个技术难点:第一是高温热辐射对结构光投射的干扰,使投射的光栅条纹的亮度比金属件本身辐射光亮度弱很多,投射的光栅条纹无法被记录,无法完成三维测量;第二是获取高温金属件形貌第三维深度值的算法比较复杂;第三是三维测量过程中大量点云处理对计算速率的要求较高。为解决上述问题本文建立了一套基于结构光的高温金属件三维测量系统,主要研究内容及成果如下:(1)对高温金属件的图像特性和高温滤波技术进行研究,通过理论与实验验证选择了基于光谱选择性原理的高温图像采集方案。方案中涉及到两种关键性滤光技术,即数字滤光技术和物理滤波技术。通过实验验证组合使用这两种技术具有可行性与可靠性,此法可以有效抑制高温对图像采集的影响,最后在程序和硬件上加以实现和选型。(2)进行了三维测量系统设计与测量实验。三维测量系统的设计包括系统总体设计,双目视觉系统的软件设计和硬件的设计。为验证系统的可靠性,选取典型的金属件实验样本进行三维测量实验,获取了金属件的视差图,得到金属件的第三维深度信息,并对第三维深度信息进行精度分析。(3)三维测量软件系统体现了测量的核心思想,而立体匹配是三维测量算法中最重要环节。本软件系统采用格雷编码和解码法实现立体匹配,经过验证此方法具有较高的精度。另外本文对一种基于REAF算法的立体匹配算法进行了研究。(4)大量点云的计算对速度提出了要求,本文采用了 CPU+GPU计算框架,将格雷编码等可大量并行化计算的部分放在GPU中处理,经过验证速度提高很多。更多还原

【Abstract】 Measurement environment of high temperature metal parts is complex,so make the traditional contact measurement method failed,the non-contact measurement technology based on structured light is an important direction to solve above problem.There are three technology difficulties in this measurement technology,first is the interference of high temperature radiation on the structure light projection,which makes the brightness of the light emitted by the metal element itself is much stronger than that of the projected grating fringes,so results in the failure of the measurement.Second is the algorithm of obtaining the three-dimensional depth of the metal parts is complex.Third is the measurement process of a large number of point clouds requires a very high calculate rate.In order to solving the above problems,this paper establishes a set of 3D measurement system of high temperature metal parts based on structured light,the main research contents and results are as follows:(1)Research on the image characteristics and high temperature filtering technology of high temperature metal parts.In this paper,the high temperature image acquisition scheme based on the principle of spectrum selectivity is selected by experiments and theories.Two key technologies are involved in the project,namely,digital filter technology and physical filter technology.In this paper,the feasibility and reliability of the combination of these two technologies are verified by experiments,which can effectively suppress the impact of high temperature on image acquisition.At last,the program is implemented and hardware type is selected.(2)Design the three dimensional measurement system and do measurement experiments.The design of three dimensional measurement system includes the overall design,the hardware design and software design of binocular vision system.At the same time,in order to verify the reliability of the system,select typical metal parts to carry out three dimensional measurement experiments,get the disparity map of metal parts and 3D depth information,and analyze the accuracy of the third depth information.(3)Three dimensional measurement software system embodies the core idea of the measurement,and stereo matching is an important part of three dimensional measurement algorithm.The software system uses the gray coding method to encode and decode the structured light grating to realize the stereo matching.It is proved that this method has high precision.In addition,a stereo matching method based on REAF algorithm is studied in this paper.(4)A large number of point cloud computing requires for speed,so in this paper,we use the framework of CPU+GPU,the part of a large number of parallel computing such as gray encoding and decoding is processed in GPU,speed is verified to improve a lot.更多还原