摘要
文中提出了一种基于相移条纹图相位分析的广角镜头畸变校正方法。首先,用大尺寸液晶平板显示器显示四幅相移量为π/2的余弦条纹图作为校正模板。然后,用广角镜头相机拍摄该校正模板,获得四幅畸变条纹图,使用四步相移算法解调径向畸变条纹图的相位分布。由于经广角镜头成像的图像中心区域几乎无畸变,利用图像中心无畸变的相位值进行数值拟合得到径向无畸变条纹图的相位分布,作为求解径向畸变相位的基准,也就是径向畸变相位分布可以根据径向畸变条纹图的相位分布与径向无畸变条纹图相位分布相减得到,再将畸变相位转换成实际的畸变量。提出的方法不需要通过特征点或特征线确定畸变模型,可以直接计算畸变图像中每个像素点的畸变量。实验结果表明,提出的方法简单、有效,具有广泛应用价值。
A distortion calibration method for wide-angle lens was proposed based on fringe-pattern phase analysis.Firstly,four standard cosine fringe-patterns with phase shift step ofπ/2,which were used as calibration templates,were shown on a large-size Liquid Crystal Display screen,and captured by the camera with wide-angle lens to obtain four distorted fringe-patterns.A four-step phase-shifting method was employed to obtain the phase distribution of the radial distorted fringe-pattern.There was no distortion within the central region of the image captured by the wide-angle lens,so the phase distribution of radial undistorted fringe-pattern,as a benchmark for computing radial distorted phase,could be acquired by performing numerical fitting by the central undistorted phase value of the distorted image.It means that the radial distorted phase distribution was computed by subtracting the phase distribution of radial distorted fringe-pattern from the phase distribution of radial undistorted fringe-pattern.Finally,the distorted phase was transformed into the actual distorted variables.There was no need to establish any kind of image distortion model by lots of characteristic points or lines.Furthermore,the radial distortion variable at each point of the distorted image can be determined by the proposed method.Experimental results show that the proposed method is simple,effective,and has wide application value.
作者
周维帅
翁嘉文
彭军政
钟金钢(指导)
Zhou Weishuai;Weng Jiawen;Peng Junzheng;Zhong Jingang(Department of Optoelectronic Engineering,Jinan University,Guangzhou 510632,China;Department of Physics,South China Agricultural University,Guangzhou 510642,China)
出处
《红外与激光工程》
EI
CSCD
北大核心
2020年第6期92-98,共7页
Infrared and Laser Engineering
基金
国家自然科学基金(61875074,61971201)
广东省光纤传感与通信技术重点实验室开放基金(暨南大学)。
关键词
畸变校正
广角镜头
条纹相位分析
distortion calibration
wide-angle lens
fringe-pattern phase analysis
