相机标定完成后，把图片转成正视图 C++

以下是使用C++和OpenCV实现相机标定并将图像转成正视图的示例代码：

#include <opencv2/opencv.hpp>
#include <iostream>

using namespace cv;
using namespace std;

int main()
{
    // 读入标定板图像
    vector<vector<Point3f>> objectPoints;
    vector<vector<Point2f>> imagePoints;
    Size boardSize(9, 6);
    vector<String> fileNames;
    glob("calibration_images/*.jpg", fileNames);
    vector<Point3f> obj;
    for(int i = 0; i < boardSize.height; ++i)
        for(int j = 0; j < boardSize.width; ++j)
            obj.push_back(Point3f(j*0.0245, i*0.0245, 0));
    for(const auto& fileName : fileNames)
    {
        Mat src = imread(fileName);
        Mat gray;
        cvtColor(src, gray, COLOR_BGR2GRAY);
        vector<Point2f> corners;
        bool found = findChessboardCorners(gray, boardSize, corners);
        if(found)
        {
            objectPoints.push_back(obj);
            imagePoints.push_back(corners);
        }
    }

    // 相机标定
    Mat cameraMatrix, distCoeffs, rvec, tvec;
    calibrateCamera(objectPoints, imagePoints, Size(640, 480), cameraMatrix, distCoeffs, rvec, tvec);

    // 图像校正
    Mat src = imread("test_image.jpg");
    Mat undistorted;
    undistort(src, undistorted, cameraMatrix, distCoeffs);

    // 投影变换
    vector<Point2f> srcPoints = {Point2f(200, 200), Point2f(600, 200), Point2f(600, 400), Point2f(200, 400)};
    vector<Point2f> dstPoints = {Point2f(0, 0), Point2f(640, 0), Point2f(640, 480), Point2f(0, 480)};
    Mat warpMatrix = getPerspectiveTransform(srcPoints, dstPoints);
    Mat dst;
    warpPerspective(undistorted, dst, warpMatrix, Size(640, 480));

    // 显示结果
    imshow("src", src);
    imshow("undistorted", undistorted);
    imshow("dst", dst);
    waitKey();

    return 0;
}

该示例代码首先读入标定板图像，并使用`findChessboardCorners()`函数检测标定板角点，然后使用`calibrateCamera()`函数对相机进行标定，得到相机矩阵和畸变系数。然后，读入测试图像，并使用`undistort()`函数对图像进行校正，去除畸变。最后，使用`getPerspectiveTransform()`函数计算投影变换矩阵，并使用`warpPerspective()`函数对图像进行投影变换，得到正视图。最后，使用`imshow()`函数显示结果，等待用户按下任意键退出程序。