尝试运行 projectPoints 时断言失败

Question

在尝试运行 projectPoints 时，我在文件 matrix.cpp 中不断收到 assertion failed(0 in cv::_InputArray::getMat,。我已经检查了我能想到的所有内容，但我无法找出问题所在。我的猜测是 calibratecamera 出了点问题，但我不知道如何找出问题所在。这是我的代码，谢谢。

using namespace cv;
using namespace std;
std::vector<cv::Point3f> Generate3DPoints()
{
  std::vector<cv::Point3f> points;

  float x,y,z;

  x=.5;y=.5;z=.5;
  points.push_back(cv::Point3f(x,y,z));

  x=0;y=0;z=0;
  points.push_back(cv::Point3f(x,y,z));

  x=-0;y=0;z=.5;
  points.push_back(cv::Point3f(x,y,z));

  x=0;y=.5;z=.5;
  points.push_back(cv::Point3f(x,y,z));

  x=0;y=-.5;z=0;
  points.push_back(cv::Point3f(x,y,z));

  x=.5;y=0;z=.5;
  points.push_back(cv::Point3f(x,y,z));

  x=.5;y=0;z=0;
  points.push_back(cv::Point3f(x,y,z));

  /*
  for(unsigned int i = 0; i < points.size(); ++i)
    {
    std::cout << points[i] << std::endl;
    }
  */
  return points;
}
int main()
{
    int numBoards = 4;
    int numCornersHor = 6;
    int numCornersVer = 9;
    int numSquares = numCornersHor * numCornersVer;
    Size board_sz = Size(numCornersHor, numCornersVer);

    VideoCapture capture = VideoCapture(0);

    vector<vector<Point3f>> object_points;
    vector<vector<Point2f>> imagePoints;
    vector<vector<Point2f>> image_points;
    vector<Point3f> objectPoints1 = Generate3DPoints();

    vector<Point2f> corners;
    int successes=0;

    Mat image;
    Mat gray_image;
    //capture >> image;
    Sleep(1000);
    capture.read(image);

    imshow("Welcome", image);
    vector<Point3f> obj;
    for(int j=0;j<numSquares;j++)
    obj.push_back(Point3f(j/numCornersHor, j%numCornersHor, 0.0f));

    while(successes<numBoards)
    {
        cvtColor(image, gray_image, CV_BGR2GRAY);
        bool found = findChessboardCorners(image, board_sz, corners, CV_CALIB_CB_ADAPTIVE_THRESH | CV_CALIB_CB_FILTER_QUADS);

        if(found)
        {
            cornerSubPix(gray_image, corners, Size(11, 11), Size(-1, -1), TermCriteria(CV_TERMCRIT_EPS | CV_TERMCRIT_ITER, 30, 0.1));
            drawChessboardCorners(gray_image, board_sz, corners, found);
            cout << "SUCESS\n";

        }
        else
            cout << "FAIL\n";

        imshow("win1", image);
        imshow("win2", gray_image);

        capture.read(image); 
        image_points.push_back(corners);
        object_points.push_back(obj);
        printf("Snap stored!\n");
        char continues;
        cout << "Press c to continue\n";
        cin >> continues;
        successes++;

        //if(successes>=numBoards)
         //   break;


    }

    Mat intrinsic = Mat(3, 3, CV_32FC1);
    Mat distCoeffs;
    vector<Mat> rvecs;
    vector<Mat> tvecs;

    intrinsic.ptr<float>(0)[0] = 1;
    intrinsic.ptr<float>(1)[1] = 1;

    calibrateCamera(object_points, image_points, image.size(), intrinsic, distCoeffs, rvecs, tvecs);

    cout << "Done\n";


    projectPoints(objectPoints1, rvecs, tvecs, intrinsic, distCoeffs, imagePoints);

    cout << "done2";

    return 0;
}

Answer 1

您正在尝试将rvecs 和tvecs 传递给函数projectPoints，它需要Mat 而不是vector<Mat>。

基本上，calibrateCamera 函数使用几张棋盘图像来估计相机的内在矩阵和失真系数。该函数还返回多个版本的外部参数（旋转+平移），一个用于您使用的每个图像。这些外部参数存储在rvecs和tvecs中。

但是，您只想在其中一张图像中投影 3D 点，因此您应该选择您想要的一组外部参数（即 rvecs[i] 和 tvecs[i]，i 对应于您在其中的图像想要投影您的对象）并仅针对这些外部参数调用projectPoints，而不是整个vectors<Mat>。