光学学报, 2018, 38 (8): 0815014, 网络出版: 2018-09-06
结合模板匹配和梯度峰值的对角标志自动提取方法 下载: 1154次
Automatic Extraction of Diagonal Markers Based on Template Matching and Peaks of Gradient Histogram
机器视觉 对角标志 自动提取 梯度峰值 模板匹配 machine vision diagonal marker automatic extraction peaks of gradient histogram template matching
摘要
为了提高视觉测量系统的自动化水平和测量精度,提出了一种结合模板匹配和梯度峰值的对角标志自动提取方法。使用旋转不变模板匹配方法得到原始图像与标准模板的相关系数矩阵,通过两次阈值筛选获取标志点候选位置。根据两条直线相交于标志中心处以及中心处灰度梯度存在多个峰值的特性,剔除非合作标志点,得到对角标志点初始坐标。通过生成对角标志理想相关模板,利用相关系数拟合极值法进行亚像素定位。实验结果表明,该方法可以正确提取复杂环境下对角标志或棋盘格图像中的角点,而且需要人工调节的参数少、稳健性强、定位精度高且通用性好,可应用于工程实践中环境光源变化较大的测量场合。
Abstract
To improve the automation level and measurement accuracy of the visual measurement system, a novel method based on template matching and peaks of gradient histogram is proposed to extract the corners of diagonal markers automatically. The rotation-invariant template matching method is used to get the coefficient correlation matrix of the original image and the standard template, and the candidate positions of markers are obtained by two thresholding selection. The false candidates are eliminated and the initial coordinates of markers are found depending on the properties, which are two lines intersecting at the center of the marker and their gray gradient of the marker with multiple peaks. The subpixel is located by generating ideal templates of diagonal markers and applying the correlation coefficient fitting extreme value method. The experimental results show that the proposed method can automatically extract the corners of diagonal markers or checkboard images in a complex environment.This method has the merits of few adjustable parameters, strong robustness, precision and universality. It can be used in measuring situations where the environment light source greatly in engineering practice.
王刚, 施忠臣, 尚洋, 于起峰. 结合模板匹配和梯度峰值的对角标志自动提取方法[J]. 光学学报, 2018, 38(8): 0815014. Gang Wang, Zhongchen Shi, Yang Shang, Qifeng Yu. Automatic Extraction of Diagonal Markers Based on Template Matching and Peaks of Gradient Histogram[J]. Acta Optica Sinica, 2018, 38(8): 0815014.