基于角度散斑相关原理开展了对喷砂表面粗糙度样块的粗糙度测量实验研究。通过对散斑图像数据的处理和分析,提出了求取角度散斑相关系数最大值的滑动相关算法。该算法能有效克服表面不平度、波度等因素的不利影响。从最佳测量条件出发,提出了最佳入射角增量的概念,并在此基础上形成了包括散斑图像采集过程和图像数据处理方法在内的一整套表面粗糙度测量方法。该测量方法的核心是对被测表面的多个激光照明区域和多个激光入射角下的远场散斑图像的采集及数据处理。实验结果表明,应用本测量方法得到的轮廓均方根偏差最佳估计值σp与表面样品给定的轮廓算术平均偏差Ra成很好的线性关系。

The surface roughness measurement is experimentally researched by using angular-speckle correlation method on blasted sand surface. Through the data processing and analysis of laser speckle patterns, moving correlation algorithm was presented to get the maximal angular-speckle correlation coefficients. This method can avoid the negative effects of surface flatness and waviness effectively. Under the prime measurement condition, the optimal incident angle increment of laser beam was given, and a method of surface roughness measurement including speckle pattern acquisition and processing was developed. The key of this method is that far-field speckle patterns in different incident angles and illumination areas of rough surface are detected and processed. The experimental results indicate that prime root-mean-square (RMS) deviation measured by this method is almost linear with the arithmetical mean deviation of the surface-samples.