大尺寸钢板测量中的激光标签精确定位

大尺寸钢板测量中的激光标签精确定位*

钱强，庞林斌，王直，白素琴

(江苏科技大学计算机科学与工程学院,江苏 镇江 212003)

摘要：在基于视觉的非接触测量法中，为了取得较好的测量精度和速度，可以结合激光测量与相机测量两种技术。在实现两种测量系统的配准过程中，对于特定标记物(比如激光标签)的精确定位是提高测量精度的关键技术。针对于此，提出了一种精确的激光标签中心定位方法。首先，利用基于GPU的梯度方向直方图(HOG)算法实现激光标签的粗定位；然后，利用图像二值化方法实现进一步的基于质心法的精确定位。在粗定位过程中，利用GPU的并行计算优势，可以实现对超大图像的实时检测，满足工业测量需求。在二值化过程中，提出了一种基于高斯差分(DOG)的二值化方法，能够取得比传统的Otsu、Bernsen等二值化方法更好的效果。实验结果表明，该方法精度可以达到1 mm以下，能够满足工业测量的需要。

关键词：GPU；HOG；激光标签；DOG；图像二值化

中图分类号：TP391.14 文献标志码：A

doi:10.3969/j.issn.1007-130X.2015.06.020

收稿日期：*2014-03-11;修回日期：2014-06-30

基金项目：上海市引进技术的吸收与创新项目(12CH-11)；江苏省产学研资助项目(BY2011143)

作者简介:

通信地址：212003 江苏省镇江市江苏科技大学计算机科学与工程学院

Address:School of Computer Science and Engineering, Jiangsu University of Science and Technology,Zhenjiang 212003,Jiangsu,P.R.China

Precisepositioningoflasertagsinlarge-scalesteelplatemeasurement

QIANQiang,PANGLin-bin,WANGZhi,BAISu-qin

(SchoolofComputerScienceandEngineering,JiangsuUniversityofScienceandTechnology,Zhenjiang212003,China)

Abstract:In order to achieve better accuracy and speed in non-contact measurement based on vision, the camera measuring technologies and the laser measuring technologies can be integrated. In the registration process of the two measuring systems, the precise positioning of a particular marker (such as laser tags) is the key technology to improve the measurement accuracy.We propose a precise positioning method of laser tags. First, the GPU-based Histogram of Oriented Gradients (HOG) algorithm is used to detect the laser tags on the steel plate.Then,the image binarization is used for further precise positioning based on the centroid method. In the process of laser tag detection,the very large image can be detected in real time to meet the requirements of industrial measurement due to the parallel computing advantage of GPU.In the process,a novel binarization method based on Difference of Gaussian (DOG) is proposed,which can obtain better results than the traditional methods such as Otsu and Bernsen. Experimental results show that the accuracy of the proposed method can reach 1 mm or less.

Keywords:graphicprocessingunit(GPU)；histogramoforientedgradients(HOG)；lasertag；differenceofgaussian(DOG)；imagebinarization

1引言

随着计算机视觉技术的不断发展，基于视觉的非接触式测量方法在工业测量、缺陷检测等方面应用越来越广泛[1～7]。现有的视觉测量系统多基于CCD相机构建，具有测量速度快、密度高等优点，但也有测量精度低等缺点[2]。激光测量的精度较高，能够避免相机测量中的畸变等问题，但存在数据点稀疏、在对大尺寸的大型目标测量中测量速度低等缺点[3]。……