机器视觉学习笔记（5）——基于OpenCV的单目摄像机标定

机器视觉学习笔记（5）——基于OpenCV的单目摄像机标定

CameraCalibrator

1.单目摄像机标定目的

2.单目摄像机标定流程

3.关键源代码说明

3.1

bool findChessboardCorners((InputArray image, Size patternSize, OutputArray corners)

void drawChessboardCorners()

void test()
{
vector<Point2f> imageCorners;
Size boardSize(9, 6);
Mat image = imread("left01.jpg");
bool found = findChessboardCorners(image, boardSize, imageCorners);
//绘制角点
drawChessboardCorners(image, boardSize, imageCorners, found);
namedWindow("test");
imshow("test", image);//角点如未全部检测出来只是红色圆圈画出角点
waitKey();
}

3.2

Class CameraCalibrator

class CameraCalibrator{

//输入点
std::vector<std::vector<cv::Point3f>> objectPoints;//世界坐标系下的点
std::vector<std::vector<cv::Point2f>> imagePoints;//像素坐标系下的点
//输出矩阵
cv::Mat cameraMatrix;//摄像机内参数矩阵
cv::Mat distCoeffs;//透镜畸变系数矩阵
//标定方式
int flag;
//用于图像去畸变
cv::Mat map1,map2;
bool mustInitUndistort;

public:
CameraCalibrator() : flag(0), mustInitUndistort(true) {};

//导入标定图片提取角点
int addChessboardPoints(const std::vector<std::string>& filelist, cv::Size & boardSize);
//添加场景点与对应的图像点
void addPoints(const std::vector<cv::Point2f>& imageCorners, const std::vector<cv::Point3f>& objectCorners);
//标定相机
double calibrate(cv::Size &imageSize);
//设置标定方式
void setCalibrationFlag(bool radial8CoeffEnabled=false, bool tangentialParamEnabled=false);
//消除透镜畸变(标定之后调用有效)
cv::Mat CameraCalibrator::remap(const cv::Mat &image);

// 获取矩阵
cv::Mat getCameraMatrix() { return cameraMatrix; }
cv::Mat getDistCoeffs()   { return distCoeffs; }
};

4.单目标定实例

int main()
{
cv::namedWindow("Image");
cv::Mat image;
std::vector<std::string> filelist;//存放标定图片路径

//生成路径，此处表示图片放在工程根目录下的chessboards文件夹
for (int i=1; i<=20; i++)
{
std::stringstream str;
str << "chessboards/chessboard" << std::setw(2) << std::setfill('0') << i << ".jpg";//图片的相对路径
std::cout << str.str() << std::endl;

filelist.push_back(str.str());
image= cv::imread(str.str());
cv::imshow("Image",image);
cv::waitKey(100);
}

CameraCalibrator cameraCalibrator;
//从棋盘格添加角点
cv::Size boardSize(6, 4);
cameraCalibrator.addChessboardPoints(
filelist,   //图片路径
boardSize); //角点数目
//标定相机
cameraCalibrator.calibrate(image.size());
//选取某张图片，消除透镜畸变
image = cv::imread(filelist[6]);
cv::Mat uImage= cameraCalibrator.remap(image);
imshow("Original Image", image);
imshow("Undistorted Image", uImage);

//打印相机内参数矩阵（3*3矩阵）
Mat cameraMatrix = cameraCalibrator.getCameraMatrix();
std::cout << " 相机内参数矩阵：" << cameraMatrix.rows << "x" << cameraMatrix.cols << std::endl;
for (int i=0; i<cameraMatrix.rows; i++)
for (int j=0; j<cameraMatrix.cols; j++)
{
cout<<setw(10)<<cameraMatrix.at<double>(i, j);
if (j==2)
cout<<endl;
}
//打印畸变系数矩阵（1*5矩阵）
Mat distCoeffs = cameraCalibrator.getDistCoeffs();
std::cout << "畸变系数矩阵：" << distCoeffs.rows << "x" << distCoeffs.cols << std::endl;
for (int i=0; i<distCoeffs.rows; i++)
for (int j=0; j<distCoeffs.cols; j++)
cout<<distCoeffs.at<double>(i, j)<<"\t";
waitKey(0);
}

5.总结