基于监控影像的结构位移跟踪监测研究

Research on Structural Displacement Tracking Monitoring Based on Surveillance Camera Videos

基于监控影像和数字图像处理技术,提出了一种表征结构位置特征点位移变化的方法。首先在结构上安置圆形标靶,用模板匹配法检测圆形标靶的初始图像坐标区域,裁剪出感兴趣区域(ROI);然后用大津法确定该区域的二值化阈值,提取标靶轮廓点坐标,使用最小二乘法将轮廓拟合成椭圆,获得椭圆中心坐标及长短轴尺寸,圆形标靶直径与椭圆长短轴的比值为转换系数η;椭圆中心坐标变化量和η的积为结构实际对应坐标方向的位移量。实验表明:在水平与竖直方向的位移加载实验中,该方法与高精度位移计对比的相对误差均<3%,可以实现mm级位移监测,精准表征结构对应特征点位移变化。

Based on the video of surveillance camera and digital image processing,a method to characterize the displacement of structural position feature points was designed.Firstly,the circular target is placed on the structure.The template matching method is used to detect the initial image coordinate region of the circular target,and the region of interest(ROI)is cut out;Then use Otsu method to determine the binarization threshold of the region,extract the coordinates of the target contour points,use the least square method to fit the contour into an ellipse,and obtain the coordinates of the center of the ellipse and the size of the long and short axis.The ratio of the diameter of the circular target to the major and minor axis is the conversion coefficientη;The product of the change of the ellipse center coordinate and the conversion coefficient is the displacement of the structure in the actual corresponding coordinate direction.The experimental results shown that the relative error of this method was less than 3%in the horizontal and vertical displacement loading experiments which compared with the high-precision displacement meter.And it can realize millimeter displacement monitoring and accurately characterize the displacement change of the corresponding characteristic points of the structure.