opencv中calibration.cpp程序

参数

相机矩阵：包括焦距（fx，fy），光学中心（Cx，Cy），完全取决于相机本身，是相机的固有属性，只需要计算一次，可用矩阵表示如下：[fx, 0, Cx; 0, fy, cy; 0,0,1];

畸变系数：畸变数学模型的5个参数 D = （k1，k2， P1， P2， k3）；

相机内参：相机矩阵和畸变系数统称为相机内参，在不考虑畸变的时候，相机矩阵也会被称为相机内参；

相机外参：通过旋转和平移变换将3D的坐标转换为相机2维的坐标，其中的旋转矩阵和平移矩阵就被称为相机的外参；描述的是将世界坐标系转换成相机坐标系的过程。

static void help(char** argv)
{printf( "This is a camera calibration sample.\n""Usage: %s\n"" -w= # the number of inner corners per one of board dimension\n"" -h= # the number of inner corners per another board dimension\n"" [-pt=

] # the type of pattern: chessboard or circles&＃39; grid\n"" [-n=] # the number of frames to use for calibration\n"" # (if not specified, it will be set to the number\n"" # of board views actually available)\n"" [-d=] # a minimum delay in ms between subsequent attempts to capture a next view\n"" # (used only for video capturing)\n"" [-s=] # square size in some user-defined units (1 by default)\n"" [-o=] # the output filename for intrinsic [and extrinsic] parameters\n"" [-op] # write detected feature points\n"" [-oe] # write extrinsic parameters\n"" [-oo] # write refined 3D object points\n"" [-zt] # assume zero tangential distortion\n"" [-a=] # fix aspect ratio (fx/fy)\n"" [-p] # fix the principal point at the center\n"" [-v] # flip the captured images around the horizontal axis\n"" [-V] # use a video file, and not an image list, uses\n"" # [input_data] string for the video file name\n"" [-su] # show undistorted images after calibration\n"" [-ws=] # Half of search window for cornerSubPix (11 by default)\n"" [-dt=] # actual distance between top-left and top-right corners of\n"" # the calibration grid. If this parameter is specified, a more\n"" # accurate calibration method will be used which may be better\n"" # with inaccurate, roughly planar target.\n"" [input_data] # input data, one of the following:\n"" # - text file with a list of the images of the board\n"" # the text file can be generated with imagelist_creator\n"" # - name of video file with a video of the board\n"" # if input_data not specified, a live view from the camera is used\n""\n", argv[0] );printf("\n%s",usage);printf( "\n%s", liveCaptureHelp );
}

离线文件

-w=4

-h=5

标定图片示例上图中，横向和纵向分别为9个交点和6个交点，对应上面的命令行的命令参数应该为： -w 9 -h 6。

• 经多次使用发现，不指定 -p参数时计算的结果误差较大，主要表现在对u0,v0的估计误差较大，因此建议使用时加上-p参数

-s=0.025

每格的宽度应设置为实际的毫米数，该参数的实际用途尚待考证。目前看来，即使设置的不准确也无大碍。我使用默认参数50。

50

-o=camera.yml

%YAML:1.0
---
calibration_time: "Fri Apr 29 17:00:05 2022"
nframes: 13
image_width: 640
image_height: 480
board_width: 9
board_height: 6
square_size: 2.5000000372529030e-02
flags: 0
camera_matrix: !!opencv-matrixrows: 3cols: 3dt: ddata: [ 5.3646256689600978e+02, 0., 3.4236865068583234e+02, 0.,5.3641493800336877e+02, 2.3554895558339965e+02, 0., 0., 1. ]
distortion_coefficients: !!opencv-matrixrows: 5cols: 1dt: ddata: [ -2.7864428555798293e-01, 6.7166038149765392e-02,1.8241702364718330e-03, -3.4339100766844229e-04, 0. ]
avg_reprojection_error: 4.0902606790992146e-01
per_view_reprojection_errors: !!opencv-matrixrows: 13cols: 1dt: fdata: [ 1.92254305e-01, 1.22073436e+00, 1.69930875e-01,1.94889039e-01, 1.59580454e-01, 1.80783704e-01, 2.36002639e-01,2.42605597e-01, 3.02249402e-01, 1.67995840e-01, 2.05065876e-01,4.64376807e-01, 1.75895900e-01 ]

输出 

-op
-oe image_list.xml

list_of_views.txt

该txt文件表示的是你在电脑上面需要用以标定的图片列表。

view00.png
view01.png
#view02.png
view03.png
view10.png
one_extra_view.jpg
上面的例子中，前面加“井号”的图片被忽略。

• 在windows的命令行中，有一种简便的办法来产生此txt文件。在CMD窗口中输入如下命令（假设当前目录里面的所有jpg文件都用作标定,并且生成的文件为a.txt）。

dir *.jpg /B >> a.txt

 launch.vs.json

{"version": "0.2.1","defaults": {},"configurations": [{"type": "default","project": "build\\bin\\Debug\\example_cpp_calibration.exe","name": "example_cpp_calibration.exe（安装）(build\\bin\\Debug\\example_cpp_calibration.exe)","args": ["-w=9 -h=6 -s=0.025 -o=camera.yml -op -oe calibration.yml"]}]
}