激光三角法在物体三维体积测量中的应用

论文总字数：27592字

摘 要

随着科技的进步，各行业对于计算机技术和数据图像处理技术的要求也越来越高。物体表面三维轮廓检测和重建技术成为现在科学研究的热门方向，并且研究成果被广泛应用于流量控制、计算机视觉、在线实时检测等领域。目前，物体表面三维轮廓测量方法可分为接触式的三坐标测量方法和非接触式的光学测量方法两大类，而由于非接触式测量不直接接触被测物体，不会对物体造成损坏，测量速度也较快，还有效率高、测量结果准确等优点，逐渐成为近年来研究三维轮廓测量技术的热点。其中，属于非接触式测量的激光三角法由于其具有非接触式测量技术的优点外，还有材料适应性广、结构简单、测距大、抗干扰能力强、测量误差小、可用于实时在线快速测量等特点，在几何量测量领域中得到了广泛的应用，这使得人们一直在探索用最现代的科学技术丰富和完善它的测量途径,力求进一步简化激光三角法的测量结构,提高测量准确度,拓宽应用范围,充分满足现代工业生产的需求。

对于激光三角法在物体三维体积测量中的应用这一课题，本文在对当前的三维轮廓测量技术做了调研和分析后，设计了一种基于激光三角法的新型三维轮廓测量系统。主要工作如下：

（1） 分析激光三角法的基本原理，比较直射式与斜射式优缺点，根据测量系统确认选取斜射式激光三角法作为测量方法。系统采用半导体激光器作为激光光源，采用高精度的线阵CCD作为光电探测器，对激光三角法测量系统进行设计，提出一种斜线扫描法进一步改进测量系统。搭建了激光三角法测量系统，并固定在三维位移平台上。

（2）由于一般情况下相机拍出图像具有畸变现象，需要对相机进行畸变校正。本课题通过研究，从寻找合适的方法来避免测量过程中的相机畸变的角度出发，提出通过调节相机成像面与激光扫描面平行的方法可以大大减少了处理图像数据过程的工作量。

（3）提取结构光光条中心线是整个系统的关键，本课题采用阈值法，阈值法计算方便、处理时间也较快，对于光强对称分布的激光斑有较高的精度。

（4）利用MATLAB平台，设计程序进行激光图像处理、提取中心线并进行拟合、计算待测物体体积等操作，最终对数据结果进行分析，计算激光三角法测三维物体体积过程的相对误差大小，证明了本课题提出的斜射式激光三角法斜线扫描测体积方法的积极意义。

通过本课题的研究，探究激光三角法在三维物体体积测量方面的重要意义，提出新想法来实现测量速度快，分辨率高，成本低等优点，以适应工业生产领域中待测物体积和三维表面的在线检测，代替以前低效率，高成本，有损坏的测量方式。

关键词：激光三角法；斜射式；斜线扫描；三维物体测量系统

Abstract

With the progress of science and technology, the industry for computer technology and data image processing technology requirements are getting higher and higher. Dimensional surface contour detection and reconstruction technology has become a popular direction of scientific research, and research results are widely used in flow control, computer vision, online real-time detection and other fields. At present, the object surface three-dimensional contour measurement method can be divided into contact three-coordinate measurement method and non-contact optical measurement method two categories, and because the non-contact measurement does not directly contact the measured object, will not cause damage to the object, Measurement speed is also faster, there are high efficiency, accurate measurement results, etc., has gradually become a hot topic in recent years to study three-dimensional contour measurement technology. Among them, the non-contact measurement of the laser triangular method because of its non-contact measurement technology advantages, there are wide material adaptability, simple structure, ranging, anti-interference ability, measurement error is small, can be used for real-time online Rapid measurement and other characteristics, in the field of geometric measurement has been widely used, which makes people have been exploring the most modern science and technology to enrich and improve its measurement approach, and strive to further simplify the laser triangulation of the measurement structure, improve the measurement accuracy Degree, broaden the scope of application, fully meet the needs of modern industrial production.

In this paper, a novel three-dimensional contour measurement system based on laser triangulation is designed and researched after the current three-dimensional contour measurement technology is researched and analyzed in the three-dimensional volume measurement of the object. The main work is as follows:

(1) Analysis of the basic principles of laser triangulation, compare the advantages and disadvantages of direct and oblique, according to the measurement system to confirm the selection of oblique laser triangulation method as a measurement method. The system uses the semiconductor laser as the laser light source, uses the high precision linear array CCD as the photo detector to design the laser triangulation measurement system, and proposes a slash scanning method to further improve the measurement system. Built a laser triangulation measurement system, and fixed on the three-dimensional displacement platform.

(2) As a result of the general situation of the camera to shoot the image with distortion, the need for distortion correction of the camera. In this paper, it is suggested that the method of adjusting the image plane of the camera and the laser scanning surface can greatly reduce the workload of the process of processing the image data from the point of view of finding the appropriate method to avoid the camera distortion in the measurement process.

(3) Extraction of the structure of the light line is the key to the whole system, the subject of the threshold method, the threshold method is easy to calculate, processing time is also faster, symmetrical distribution of light for the laser spot has a higher accuracy.

(4) Using MATLAB platform, designing the program to carry out laser image processing, extracting the center line and fitting to calculate the volume of the object to be measured and so on. Finally, the data result is analyzed and the relative error of the three-dimensional object volume process is calculated by laser triangulation This paper proves the positive significance of the oblique laser triangulation slanting method.

Through the research of this subject, the significance of the laser triangular method in the measurement of the volume of the three-dimensional objects is explored, and new ideas are put forward to realize the advantages of fast measurement speed, high resolution and low cost to adapt to the volume of the objects to be measured in the industrial production field and the three-dimensional Surface of the on-line detection, instead of the previous low efficiency, high cost, damage to measure ways.

Keywords: laser triangulation；oblique incidence；slash scan；three-dimensional object measuring system

目 录

摘 要 I

Abstract II

目 录 IV

第一章 绪论 1

1.1 选题背景与意义 1

1.2 国内外研究现状 1

1.2.1 激光三角法的实验研究 1

1.2.2 激光三角法的误差研究 2

1.3 论文研究内容及意义 2

第二章 测量原理及系统 4

2.1 结构光测量原理 4

2.2 激光三角法测量原理 4

2.2.1 激光三角法的含义 5

2.2.2 直射式激光三角法 6

2.2.3 斜射式激光三角法 7

2.2.4 两种入射方法的优缺点 8

2.2.5 激光三角法测量系统对本实验的意义 8

2.3 本章小结 9

第三章 测量系统设计与改进 10

3.1 测量系统设计 10

3.1.1 系统流程 10

3.1.2 系统硬件设计 10

3.1.3 系统软件设计 15

3.1.4 测量系统搭建 16

3.1.5 系统的创新应用 17

3.2 本章总结 18

第四章 图像处理 19

4.1 提取结构光条中心线 19

4.1.1 极值法 19

4.1.2 阈值法 19

4.1.3 灰度重心法 19

4.1.4 高斯曲线拟合法 20

4.1.5 提取中心线方法的选取 20

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