平面标定法在闪电光学观测中的应用

谢正帅; 吕伟涛; 马颖; 齐奇; 武斌; 姜睿娇; 孙秀斌; 陈绿文; 杜赛; 颜旭; 肖桐

doi:10.16032/j.issn.1004-4965.2022.040

平面标定法在闪电光学观测中的应用

doi: 10.16032/j.issn.1004-4965.2022.040

谢正帅¹,
吕伟涛^1, ,,
马颖¹,
齐奇¹,
武斌¹,
姜睿娇¹,
孙秀斌²,
陈绿文³,
杜赛³,
颜旭³,
肖桐⁴

1.
中国气象科学研究院灾害天气国家重点实验室/雷电物理和防护工程实验室，北京 100081
2.
成都信息工程大学，四川成都 610225
3.
中国气象局广州热带海洋气象研究所，广东广州 510641
4.
中国铁道科学研究院集团有限公司通信信号研究所，北京 100081

基金项目:

国家重点研究发展计划 2017YFC1501504

国家自然科学基金项目 42175108

中国气象科学研究院基本科研业务费专项 2021Z011

中国铁道科学研究院集团有限公司院基金课题 2020YJ171

详细信息

通讯作者:
吕伟涛，河南省人，研究员，博士，主要研究方向为大气电学。E-mail：lyuwt@foxmail.com

中图分类号: P427.3
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- 文章访问数: 99
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- 被引次数: 0
出版历程
- 收稿日期: 2021-02-04
- 修回日期: 2022-03-18
- 网络出版日期: 2022-08-16
- 刊出日期: 2022-06-20

APPLICATION OF PLANE CALIBRATION METHOD IN OPTICAL OBSERVATION OF LIGHTNING

1.
State Key Laboratory of Severe Weather/Laboratory of Lightning Physics and Protection Engineering, Chinese Academy of Meteorological Sciences, Beijing 100081, China
2.
Chengdu University of Information Technology, Chengdu 610225, China
3.
Guangzhou Institute of Tropical and Marine Meteorology, CMA, Guangzhou 510641, China
4.
Institute of Communication and Signaling, China Academy of Railway Sciences Group Co., Ltd., Beijing 100081, China

摘要

摘要: 针对闪电光学观测资料定量分析的需求，采用张正友平面标定法结合便携式平面靶标，实现了闪电外场试验中光学观测设备的现场标定，为消除光学系统成像畸变对闪电通道特征分析的影响提供了一种便捷的途径。使用此方法对广州高建筑物雷电观测站(TOLOG)的6套闪电光学观测设备进行了标定，结果表明：光学观测设备搭载同类型镜头时，焦距越短图像的畸变越明显; 图像中视线与光轴的夹角越大，径向畸变的影响越明显，采用鱼眼镜头获得的闪电通道图像在靠近边缘的位置畸变的影响会超过25%;通过对配备焦距为8 mm鱼眼镜头的单反相机以及配备焦距为8 mm广角镜头的高速摄像机同时获取的闪电光学同步资料进行畸变校正后，发现获取的图像畸变校正前后闪电通道总体长度差异分别为12.9%和4.5%;经过畸变校正后不同设备获取的闪电通道图像比原图拥有更好的一致性。
- 摄像机标定 /
- 平面靶标 /
- 畸变校正 /
- 闪电光学观测
Abstract: This study is aimed to quantitatively analyze the observational data of various optical equipment at the observation station of the Tall-Object Lightning Observatory in Guangzhou (TOLOG), and also realize the on-site calibration of the lightning optical observation equipment in field tests. We adopted the plane calibration method and calibrated the six types of lightning optical observation equipment using a portable plane calibration target. The results showed that the shorter the focal length of the lens, the greater the distortion coefficient. In the image, the influence of radial distortion was also positively associated with the angle between the line of sight and the optical axis. The distortion of the edge of the lightning channel captured by fish eye lens would be more than 25%. After performing distortion correction on the lightning optical data collected by the Nikon SLR D7100 camera equipped with a Nikon 8 mm fisheye lens and a high-speed camera equipped with a Computar 8 mm wide-angle lens, we found that the total length of the lightning channel before and after image distortion correction differed by 12.89% and 4.45%, respectively. It showed that the distortion caused by the focal length and the type of lens had different effects on the lightning channel image. After distortion correction, however, the shape and length of the lightning channel obtained by different optical devices had a good consistency. This research provides a convenient method to eliminate the influence of optical system imaging distortion on the analysis of lightning channel characteristics.
- camera calibration /
- plane calibration target /
- distortion correction /
- optical observation of lightning

HTML全文

图 1 平面棋盘格靶标及特征点(角点)选取

下载: 全尺寸图片幻灯片

图 2 用于相机标定的靶标照片(a)及广州高建筑物雷电观测站光学观测设备的视野(b)

下载: 全尺寸图片幻灯片

图 3 闪电光学观测设备图像校正前后像点与光心的角度受畸变影响的相对大小

下载: 全尺寸图片幻灯片

图 4 TOLOG主站单反相机(D7100-8)于2018年7月6日拍摄的一次广州塔上行闪电个例

(a)为资料原图，(b)是将(a)经过摄像机标定后去除畸变的照片。(c)为(a)(b)以光心为基点的叠加图，并分别将校正前后闪电通道标记成蓝色和红色(图c进行了对比度增强)。

下载: 全尺寸图片幻灯片

图 5 以图像光心为圆心的闪电通道同心圆分布图

下载: 全尺寸图片幻灯片

图 6 校正前后区域内闪电通道相对长度随区域与图像光心的夹角的关系

下载: 全尺寸图片幻灯片

图 7 TOLOG主站高速摄像机(SA3)捕捉到的广州塔上行闪电光学同步观测资料

(a)、(b)分别为资料原图和畸变校正后的图像。(c)为(a)(b)以光心为基点的叠加图，并分别将校正前后闪电通道标记成蓝色和红色(图c进行了对比度增强、灰度化处理)。

下载: 全尺寸图片幻灯片

图 8 在不同设备获取的同步观测资料图像中选取闪电通道的相同拐点作为特征点

下载: 全尺寸图片幻灯片

表 1 TOLOG闪电光学观测设备的标定参数

光学设备编号	镜头类型	焦距(mm)	畸变系数		内部参数
光学设备编号	镜头类型	F	k₁	k₂	u₀	v₀	f_x	f_y
SA3	广角镜头	8	-0.162	0.094	509	481	485	488
SAZ		14	-0.078	0.039	517	498	716	718
SA5		20	-0.106	0.087	517	514	1026	1030
D7100-20		20	-0.099	0.051	2 451	1 674	4 237	4 226
D7100-8	鱼眼镜头	8	-0.283	0.060	2 387	1 566	2 073	2 068
D7100-16	鱼眼镜头	16	-0.109	0.088	2 987	2 041	3 958	3 971

下载: 导出CSV

参考文献(27)

[1]	郄秀书, 张其林, 袁铁, 等. 雷电物理学[M]. 北京: 科学出版社, 2013.
[2]	SCHONLAND, B F J., MALAN, D J J, COLLENS, H. 1935 Progressive lightning Ⅱ[M], Proc. R. Soc. London, Ser. A, 152, 595 625, doi: 10.1098/rspa.1935.0210.
[3]	BERGER, K, VOGELSANGER E. Photographische Blitzuntersuchungen der Jahre 1955-1965 a uf dem Monte San Salvatore[J]. Bull Schweiz Elektrotech Ver, 57, 599 - 620.
[4]	LU W, CHEN L, MA Y, et al, Lightning attachment process involving connection of the downward negative leader to the lateral surface of the upward connecting leader[J]. Geophys Res Lett, 2013, 40(20): 5 531-5 535.
[5]	马颂德, 张正友. 计算机视觉——理论与算法基础[M]. 北京: 科学出版社, 1998.
[6]	ABDEL-AZIZ Y I, KARARA H M. Direct Linear Transformation from Comparator Coordinates into Object Space Coordinates in CloseRange Photogrammetry[J]. Photogrammetric Engineering & Remote Sensing, 81(2): 103-107.
[7]	STURM P F, MAYBANK S J. On Plane-Based Camera Calibration: A General Algorithm, Singularities, Applications[C]. IEEE Computer Society Conference on Computer Vision & Pattern Recognition, 1999.
[8]	TSAI R. A versatile camera calibration technique for high-accuracy 3D machine vision metrology using off-the-shelf TV cameras and lenses [J]. 1987, RA3(4): 323-344.
[9]	孟晓桥, 胡占义. 摄像机自标定方法的研究与进展[J]. 自动化学报, 2003, 29(1): 110-124.
[10]	ZHANG Z Y. A flexible new technique for camera calibration[R]. Microsoft Corporation, NSR-TR-98-71, 1998.
[11]	ZHANG Z Y. Flexible Camera Calibration by Viewing a Plane from Unknown Orientations[C]//Proceedings of IEEE International Conference on Computer Vision, Corfu, Greece, Sep 20-27, 1999, 1: 1-8.
[12]	吴福朝. 计算机视觉中的数学方法[M]. 北京: 科学出版社, 2008: 46-52.
[13]	杨必武, 郭晓松. 摄像机镜头非线性畸变校正方法综述[J]. 中国图象图形学报, 2005, 10(3): 269-274. DOI:10.3969/j.issn.1006- 8961.2005.03.001.
[14]	BROWN D C. Close-range camera calibration[J]. Photogrammetric Engineering, 1971, 37(8): 855-866.
[15]	张广军. 视觉测量[M]. 北京. 科学出版社, 2008: 34-42.
[16]	WEI G, MA S. Implicit and explicit camera calibration: Theory and experiments[J]. Transactions on Pattern Analysis and Machine Intelligence, 1994, 16(5): 469-480
[17]	余明浪, 魏振忠, 孙军华. 基于柔性平面靶标的摄像机现场标定方法[J]. 北京航空航天大学学报, 2009(3): 84-87.
[18]	HARRIS C, STEPHENS M. A Combined Corner and Edge Detection[C]//InProc. 4th Alvey Vision Conel988: 189-192.
[19]	WEI G Q, MA S D. Implicit and Explicit Camera Calibration: Theory and Experiments[J]. IEEE Transactions on Pattern Analysis and Machine Intelligence, 1994, 16(5): 469-480.
[20]	吕伟涛, 陈绿文, 马颖, 等. 广州高建筑物雷电观测与研究10年进展[J]. 应用气象学报, 2020, 31(2): 129-145. DOI: 10.11898/1001- 7313.20200201
[21]	武斌, 吕伟涛, 齐奇, 等. 双向先导正端突然延展现象的高速摄像观测[J]. 应用气象学报, 2020, 31(2): 146-155. DOI: 10.11898/1001- 7313.20200202
[22]	齐奇, 吕伟涛, 武斌, 等. 广州两座高建筑物上闪击距离的二维光学观测[J]. 应用气象学报, 2020, 31(2): 156-164. DOI: 10.11898/1001- 7313.20200203
[23]	QI Q, LU W, MA Y, et al. High-speed video observations of the fine structure of a natural negative stepped leader at close distance[J]. Atmospheric Research, 2016, 178-179: 260-267.
[24]	WU B, LYU W, QI Q, et al. Synchronized Two-Station Optical and Electric Field Observations of Multiple Upward Lightning Flashes Triggered by a 310-kA +CG Flash[J]. Journal of Geophysical Research: Atmospheres, 2019, 124(2): 1 050-1 063.
[25]	QI Q, LYU W, MA Y, et al. High-speed video observations of natural lightning attachment process with framing rates up to half a million frames per second[J]. Geophysical Research Letters, 2019, 46(12): 12 580-12 587.
[26]	迟泽英, 陈文建. 应用光学与光学设计基础[M]. 北京: 高等教育出版社, 2013.
[27]	WILLETT J, LE VINE D, IDONE V. Lightning return stroke current waveforms aloft from measured field change, current, and channel geometry[J]. Journal of Geophysical Research: Atmospheres, 2008, 113(D7): D07305.