Unable to use it with OpenCV 4.5.0

[Smithangshu]

I am using custom pattern image to get calibration result using this library along with OpenCV 4.5.0 and I am getting following error.

number of matched points 201 number of filtered points 82 OpenCV: terminate handler is called! The last OpenCV error is: OpenCV(4.5.0) Error: Assertion failed (nimages > 0) in calibrateCameraRO, file C:\OpenCV\opencv\sources\modules\calib3d\src\calibration.cpp, line 3694

#include "opencv2/ccalib/randpattern.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/calib3d.hpp"
#include <vector>
#include <iostream>
#include <time.h>
using namespace std;
using namespace cv;

static void saveCameraParams(const string &filename, Size imageSize, float patternWidth,
                             float patternHeight, int flags, const Mat &cameraMatrix, const Mat &distCoeffs,
                             const vector<Mat> &rvecs, const vector<Mat> &tvecs, double rms)
{
    FileStorage fs(filename, FileStorage::WRITE);
    time_t tt;
    time(&tt);
    struct tm *t2 = localtime(&tt);
    char buf[1024];
    strftime(buf, sizeof(buf) - 1, "%c", t2);

    fs << "calibration_time" << buf;

    if (!rvecs.empty())
        fs << "nframes" << (int)rvecs.size();

    fs << "image_width" << imageSize.width;
    fs << "image_height" << imageSize.height;
    fs << "pattern_width" << patternWidth;
    fs << "pattern_height" << patternHeight;

    fs << "flags" << flags;

    fs << "camera_matrix" << cameraMatrix;
    fs << "distortion_coefficients" << distCoeffs;

    fs << "rms" << rms;

    if (!rvecs.empty() && !tvecs.empty())
    {
        CV_Assert(rvecs[0].type() == tvecs[0].type());
        Mat bigmat((int)rvecs.size(), 6, rvecs[0].type());
        for (int i = 0; i < (int)rvecs.size(); i++)
        {
            Mat r = bigmat(Range(i, i + 1), Range(0, 3));
            Mat t = bigmat(Range(i, i + 1), Range(3, 6));

            CV_Assert(rvecs[i].rows == 3 && rvecs[i].cols == 1);
            CV_Assert(tvecs[i].rows == 3 && tvecs[i].cols == 1);
            //*.t() is MatExpr (not Mat) so we can use assignment operator
            r = rvecs[i].t();
            t = tvecs[i].t();
        }
        //cvWriteComment( *fs, "a set of 6-tuples (rotation vector + translation vector) for each view", 0 );
        fs << "extrinsic_parameters" << bigmat;
    }
}

int main(int argc, char const *argv[])
{
    randpattern::RandomPatternCornerFinder finder(6, 5.7, 20,0,1,1);
    Mat pattern = imread("PyramidPattern.jpg", IMREAD_GRAYSCALE);
    finder.loadPattern(pattern);
    Mat image = imread("PyramidPatternTest.jpg", IMREAD_GRAYSCALE);
    finder.computeObjectImagePointsForSingle(image);
    vector<Mat> objectPoints = finder.getObjectPoints();
    vector<Mat> imagePoints = finder.getImagePoints();

    Mat K;
    Mat D;
    vector<Mat> rvec, tvec;
    double rms = calibrateCamera(objectPoints, imagePoints, image.size(), K, D, rvec, tvec);
    saveCameraParams("out_camera_params.xml", image.size(), 6, 5.7, CALIB_FIX_PRINCIPAL_POINT, K, D, rvec, tvec, rms);

    return 0;
}

Marker Pattern

Test Image to

And whenever I trying to see value of objectPoints, imagePoints variable in debugger I am getting {...} instead collection of Mat inside vector.

Please help me to get rid of this issue.