基于光截图像测量技术的轮对外形尺寸动态检测系统中,CCD摄像机拍摄的车轮外形图像畸变严重。本文分析了造成图像畸变和失真的原因,设计了二次、三次A、四次标定模型,利用标定棋格图定性比较了各种标定模型的标定效果,确定了适合本测量系统的标定算法。针对该标定算法,定量分析了视场中心区域和视场边缘区域的校正效果,并对实际测量中获得的高速动车组车轮外形轮廓光截图像进行了校正,定性展示了校正前后的效果。现场试验表明,本文提出的标定算法取得了很好的效果,标定精度达到0.1mm,满足轮对动态检测需要。
Images captured from CCD cameras installed along railway are heavily distorted in wheel profile dynamic inspection system based on light-section method and image measurement technique. This paper analyzed causes of image distortion captured by CCD cameras, and designed the factorial of 2, 3, 4 calibration model. The results of each calibration model were compared by processing the same distortion image of checkerboard. And the calibration model, which is fit to Wheel Dynamic Inspection System, was selected. Based on selected calibration model, revised results of center district and outer district of image were analyzed quantitatively. Furthermore, the selected calibration model was applied on wheel profile image of high speed train captured by Wheel Dynamic Inspection System and the revised result of wheel profile was given. Field test shows that the designed calibration algorithm achieves a high precision of 0. 1 mm, which meets the demand of wheel inspection in motion.