基于光栅投影的钢板孔洞缺陷测量

针对基于光栅投影的钢板外观质量检测中孔洞检 测缺陷精度不高的问题,提出一种基于双投影的孔 洞缺陷检测方法。在钢板上方等间距设置两个线激光阵列,交替投影等间隔明暗分布的光栅 场,CCD相机 分别采集两个方向上投影到钢板表面的云纹图像,利用相移法分别求解出两个方向云纹图像 的相位信息, 然后分别重建得到钢板两个方向的三维轮廓。通过背景二值化定位投影盲区,将两个方向的 重建三维轮廓 进行融合,从而完成钢板的三维重建,实现钢板表面孔洞缺陷的测量。实验结果证明:钢板 的厚度测量精度为0.05 mm,孔洞缺陷测量精度可以提高到0.1 mm。

Measurement of hole defects in steel plates based on grating projection

The surface quality of steel plate can be measured by grating projecti on method,but the accuracy of detecting hole defects is not enough high.In this paper,in view of the above q uestion,a method of hole defects detection based on double projections is proposed.Two line laser arrays are arr anged at equal intervals above the steel plate,and the equally spaced light and dark grating fields are alternatel y projected.The CCD camera separately collects moire images projected onto the surface of the steel plate i n the left and right directions.The phase shift method is used to solve phase information of moire images in the lef t and right directions,and then reconstructs the three-dimensional contour of the left and right directions.Th rough the binarization of moiré background images to locate the projection blind zone or the discontinuous zone, and then the reconstructed three-dimensional morphologies of the left and right directions a re merged,thereby completing the three-dimensional reconstruction of the steel plate and realizing the measureme nt of the hole defect on the steel plate surface.Experimental results show that the thickness measurement accuracy of the steel plate is 0.05mm,and the hole defect measurement accuracy can be improved to 0.1mm.