摘要
针对孔内表面缺陷尺寸测量难的问题,提出一种内窥图像校正方法以实现孔内表面尺寸测量。根据内窥成像原理,在考虑应用场景几何约束的情况下,将图像畸变分解为周向畸变和轴向畸变,将校正模型中的参数简化为图像中心坐标和一个非线性增长函数,进而提高了内窥镜图像边缘区域的校正精度。采用Hough变换和图像像素标定的方法得到相关参数,为克服轴向校正对标定结果的依赖,采用神经网络算法拟合包含像素相对位置和孔径的轴向校正函数。实验结果表明,基于像素标定的6组实验的平均测量误差为1.95%,准确度高。对于不具备标定条件的孔内表面缺陷,采用轴向校正函数进行校正和测量,3组实验的平均测量误差为6.75%,结果较为理想。所提出的校正方法通用性好、准确率高,可用于孔类零件及管道的自动化检测和智能检测。
Objective Holes are the most common form of parts in machining and manufacturing.Enterprises have been long suffered from the inner surface defect detection of holes,especially the measurement of inner surface size.With the development of image processing technology and miniaturization of imaging elements,inner surface defect detection based on endoscopic images has been widely used in mechanical manufacturing,aerospace,and other fields.When endoscopes are applied to detect the inner surface defects,the real inner surface is parallel to the main optical axis of the lens and exhibits a circular scattering distribution on the imaging plane,which is not conducive to identifying the contour and size of the defects.Aiming at the difficulty in measuring the inner surface defect size of the hole,this paper proposes an endoscope image correction method to realize the inner surface size measurement.Methods According to the mapping relationship between spatial coordinates and phase plane coordinates in the endoscopic imaging system,the endoscopic image distortion is divided into circumferential distortion and axial distortion.In the case of adding geometric constraints in the application scene,the parameters in the correction model are simplified to a central coordinate and a nonlinear parameter,which improves the correction accuracy of the edge region of the endoscope image.The Hough transform and difference expansion are adopted to process the endoscopic image to realize the circumferential correction,and the axial correction is performed by pixel calibration and nonlinear stretching of the circumferential corrected image.The paper utilizes the neural network algorithm to fit the axial correction function including the relative positions of pixels and apertures based on the calibration experiments of different apertures,thus overcoming the dependence of the axial correction on the calibration results.Additionally,the measurement of inner surface defects of holes without calibration conditions is obtained.Results and Disc
作者
盛强
郑建明
陈婷
杨秀秀
高羡明
Sheng Qiang;Zheng Jianming;Chen Ting;Yang Xiuxiu;Gao Xianming(School of Mechanical and Precision Instrument Engineering,Xi′an University of Technology,Xi′an,710048,Shaanxi,China;College of Mechanical and Electrical Engineering,Shaanxi University of Science and Technology,Xi′an,710021,Shaanxi,China;School of Economics and Management,Xi′an University of Technology,Xi′an 710054,Shaanxi,China)
出处
《光学学报》
EI
CAS
CSCD
北大核心
2023年第3期114-123,共10页
Acta Optica Sinica
基金
国家自然科学基金(51905328)。
关键词
测量
畸变校正
内窥图像
尺寸测量
孔内表面
图像处理
measurement
distortion correction
endoscopic images
size measurement
inner surface of hole
image processing
