inverse perspective mapping (IPM) on the capture from camera feed?

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Hi, I am an OpenCV noobie looking to perform IPM on the input camera feed, without having to set the camera angles? (X, Y, Z axes) my modification of the code obtained from the following GitHub link: https://gist.github.com/anujonthemove... where I have manully added X as 43 rad, Y and Z as 90 rad, after trying out the windowed example, is,

#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>


#include <iostream>


using namespace std;
using namespace cv;
#define PI 3.1415926


int frameWidth = 640;
int frameHeight = 480;

int main(int argc, char const *argv[]) {

    if(argc < 2) {
      cerr << "Usage: " << argv[0] << " /dev/video1" << endl;
      cout << "Exiting...." << endl;
      return -1;
    }

    // get file name from the command line
    string filename = argv[1];

    // capture object
    VideoCapture capture(filename);

    // mat container to receive images
    Mat source, destination;

    // check if capture was successful
    if( !capture.isOpened()) throw "Error reading video";


    int alpha_ = 90, beta_ = 90, gamma_ = 90;
    int f_ = 500, dist_ = 500;

    // namedWindow("Result", 1);

    //createTrackbar("Alpha", "Result", &alpha_, 180);
    //createTrackbar("Beta", "Result", &beta_, 180);
    //createTrackbar("Gamma", "Result", &gamma_, 180);
    //createTrackbar("f", "Result", &f_, 2000);
    //createTrackbar("Distance", "Result", &dist_, 2000);

    while( true ) {

        capture >> source;

        resize(source, source,Size(frameWidth, frameHeight));

        double focalLength, dist, alpha, beta, gamma; 

        alpha = 43;
        beta =((double)beta_ -90) * PI/180;
        gamma =((double)gamma_ -90) * PI/180;
        focalLength = (double)f_;
        dist = (double)dist_;

        Size image_size = source.size();
        double w = (double)image_size.width, h = (double)image_size.height;


        // Projecion matrix 2D -> 3D
        Mat A1 = (Mat_<float>(4, 3)<< 
            1, 0, -w/2,
            0, 1, -h/2,
            0, 0, 0,
            0, 0, 1 );


        // Rotation matrices Rx, Ry, Rz

        Mat RX = (Mat_<float>(4, 4) << 
            1, 0, 0, 0,
            0, cos(alpha), -sin(alpha), 0,
            0, sin(alpha), cos(alpha), 0,
            0, 0, 0, 1 );

        Mat RY = (Mat_<float>(4, 4) << 
            cos(beta), 0, -sin(beta), 0,
            0, 1, 0, 0,
            sin(beta), 0, cos(beta), 0,
            0, 0, 0, 1  );

        Mat RZ = (Mat_<float>(4, 4) << 
            cos(gamma), -sin(gamma), 0, 0,
            sin(gamma), cos(gamma), 0, 0,
            0, 0, 1, 0,
            0, 0, 0, 1  );


        // R - rotation matrix
        Mat R = RX * RY * RZ;

        // T - translation matrix
        Mat T = (Mat_<float>(4, 4) << 
            1, 0, 0, 0,  
            0, 1, 0, 0,  
            0, 0, 1, dist,  
            0, 0, 0, 1); 

        // K - intrinsic matrix 
        Mat K = (Mat_<float>(3, 4) << 
            focalLength, 0, w/2, 0,
            0, focalLength, h/2, 0,
            0, 0, 1, 0
            ); 


        Mat transformationMat = K * (T * (R * A1));

        warpPerspective(source, destination, transformationMat, image_size, INTER_CUBIC | WARP_INVERSE_MAP);

        imshow("Result", destination);
        waitKey(200);
    }


    return 0;
}

The Input:

and the output:

Is it possible to make the camera automatically convert the image into its IPM transform without having to set the angles (Here, X)?

Any help would be highly appreciated.Thanks in advance.

UPDATE I used the same example to assign values to an input video's angles, instead of using a png input. The results and values are shown below, It will be helpful ... (more)