一种基于自适应角点检测的非量测畸变校正方法  

Non-Metric Distortion Correction Method Based on Adaptive Corner Detection

作　　者：胡均平[1] 宋菲菲 罗春雷[1] 黄强 Hu Junping;Song Feifei;Luo Chunlei;Huang Qiang(College of Mechanical and Electrical Engineering,Central South University,Changsha,Hunan410075,China)

机构地区：[1]中南大学机电工程学院,湖南长沙410075

出　　处：《激光与光电子学进展》2021年第12期159-165,共7页Laser & Optoelectronics Progress

基　　金：国家自然科学基金(51175518)。

摘　　要：图像非线性畸变降低图像检测和分类的准确率,因此畸变校正是图像处理的一个重要预处理步骤。为此,提出一种基于自适应角点检测的非量测畸变校正方法来更好地解决图像畸变问题。首先,以畸变棋盘格图像作为研究对象,以自适应角点检测获取亚像素级角点坐标作为输入信息,基于直线投影不变性建立畸变损失函数并设置基于曲率半径的权重系数调整各曲线的畸变量。然后,采用非线性优化方法标定畸变系数和畸变中心实现畸变校正。设计两组实验:标准图像仿真实验和真实图像实验。标准图像实验中噪声值σ=1时,本文方法的畸变系数k1相对误差为0.733%,畸变系数k2相对误差为4.933%,接近真值。真实图像实验中,本文方法的平均直线度仅为0.5152pixel,表明校正精度高,平均运算时间约为8.4s,表明校正效率较好。两组实验结果表明,本文方法可行、准确、高效。The accuracy of image detection and classification will be reduced by image nonlinear distortion,hence distortion correction is an important preprocessing step in image processing.This paper proposes a non-metric distortion correction method based on adaptive corner detection to better solve the image distortion problem.First,the distorted checkerboard image is used as the research object,and the sub-pixel corner coordinates obtained by adaptive corner detection are used as input information.The distortion loss function is established based on the invariance of straight-line projection and the weight coefficient based on the radius of curvature is set to adjust the distortion of each curve.Then,the nonlinear optimization method is used to calibrate the distortion coefficient and the distortion center to realize the distortion correction.Two sets of experiments are designed:standard image simulation experiment and real image experiment.At the noise level σ=1 in standard image simulation experiment,the relative error of distortion parameter k1 is 0.733%,and the relative error of the distortion coefficient is 4.933%,which is close to the true value.In the real image experiment,the average straightness of the method in this paper is only 0.5152 pixel,which shows that the correction accuracy is high,and the average operation time is about 8.4 s,which shows that the correction efficiency is better.Experimental results show that the method is feasible,accurate and efficient.

关 键 词：图像处理 自适应 角点检测 投影不变性 径向畸变 图像校正 

分 类 号：TP391.4[自动化与计算机技术—计算机应用技术]