【作者】 涂辉；

【导师】 周莉萍；

【作者基本信息】 华中科技大学 ， 测试计量技术及仪器， 2006， 硕士

【摘要】 本文提出用一种新型的无衍射光—无衍射结构光作为入射光进行物体表面形貌的三角测量。这种新型光束不仅具有传统无衍射光的特点,且光斑为线性结构。它为表面形貌测量提供了一种优良的光源,使测量系统能同时满足测量范围大,分辨率高和测量速度快的要求。基于这种光源的测量系统可用于快速测量大型工件三维表面形貌,如汽车车身、飞机构件等;也可用在数控机床中,作为反求工程中的快速测量系统。本文围绕无衍射结构光的特性、激光三角测量原理和方法、摄像机定标以及图像预处理等进行了研究,主要工作和创新如下:论述了物体表面形貌的多种测量方法并对其进行分析比较。论证了无衍射光束三角测量的原理和方法以及无衍射结构光三角测量的原理和方法,最终确定以无衍射结构光代替传统高斯光作为激光三角测量的入射光,解决了传统激光三角测量无法同时满足高分辨率、高精度与大测量范围要求的问题。由于无需调焦机构,系统具有结构简单、测量速度快的特点。文中给出了实验装置和对应的实验结果。提出了图像预处理的方法。本文采用CCD摄像机进行图像采集,并利用Matlab软件的图像处理功能对采集的图像文件进行了去噪、增强对比度等处理,提高了图像质量。提出了一种两阶段的摄像机定标方法。该方法通过空间坐标变换,方便地求出摄像机的内外参数,从而获得被测物体的三维信息。模拟实验表明:定标所得的内外参数与真实值非常接近,满足高精度测量的要求。更多还原

【Abstract】 This dissertation states a novel non-diffraction structure light (NDSL) which is applied to triangulation measurement as an incident light . This novel light not only has characteristics of traditional non-diffraction beam, but also it is linear structure. It is a perfect lighting source for surface topography measurement, which can satisfy the requirements of large measurement range, high resolution and real-time measurement of the system. Measurement system based on this light can be used for quick 3D surface topography measurement of large workpieces e.g. bodies of automobiles and spacecrafts. It can also be used in NC machine tools as a system for quick measurement with derivation engineering. This dissertation states the research results of its characteristics, laser triangulation measurement theory and method, CCD calibration and image prelimilary processing. The major work and innovation are showed as following:All kinds of measurement methods of object surface topography are disserted and analyzed and compared. Instead of the traditional Gaussian light,non-diffraction structure light is adopted as an incident light in laser triangulation measurement. Then,high resolution,high accuracy and large measuring range can be satisfied in the meanwhile.For NDSL,since no focal adjustment device is needed ,the system structure will be simplified and the measuring speed will be quickened.In this dissertation,the experimental structure with NDSL and the relevant experimental results have been given.A research on image sample and process system of NDSL is made. A method of image prelimilary processing is proposed.NDSL’s images are sampled by CCD , and then the sampled images are denoised, their contrasts are strengthened by Matlab software to improve quality.A method of CCD calibration with two stages is proposed. The method could obtain internal and outer parameters conveniencely by transform of spacial coordinate and acquire the 3-D information of the object on-measure.The simulated experiment shows that the in-and-out parameters is close to the real value,which meet the demand for measuring precision.更多还原