How to merge two images in opencv?

Question

I have calculated homography ,taken out perspective transform .I am able two display two images in one window but unable to merge them.Here are my example images->

The code I am using thiscode ->

cv::warpPerspective(image2,warpresult2,homography,cv::Size(2*image2.cols,image2.rows));


Mat imgResult(image1.rows,2*image1.cols,image1.type());

Mat roiImgResult_Left = imgResult(Rect(0,0,image1.cols,image1.rows)); 
Mat roiImgResult_Right = imgResult(Rect(image1.cols,0,image2.cols,image2.rows)); 

Mat roiImg1 = image1(Rect(0,0,image1.cols,image1.rows));
Mat roiImg2 = warpresult2(Rect(0,0,image2.cols,image2.rows));

roiImg1.copyTo(roiImgResult_Left); //Img1 will be on the left of imgResult
roiImg2.copyTo(roiImgResult_Right); //Img2 will be on the right of imgResult

imshow("Finalimg",imgResult);
imwrite("C:\\OpenCv_Projects\\outputimage.jpg",imgResult);
cvWaitKey(0);

I think the problem is in the coordinates that i am giving roiImgResult_right.

And the Output Image is -> As you can see the images are not properly merge and there is black area on the right side.how to remove that also?

Answer 1

OpenCV already has image stitching implemented. If you compile with "-D BUILD_EXAMPLES", you can use the binary stitching_detailed. The usage is simple: ./stitching_detailed img1 img2 ...

Or, you can just use the stitcher class (example from here):

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/stitching/stitcher.hpp"

using namespace std;
using namespace cv;

bool try_use_gpu = false;
string result_name = "result.jpg";

int main(int argc, char* argv[])
{
    vector<Mat> imgs;
    // add images...

    Mat pano;
    Stitcher stitcher = Stitcher::createDefault(try_use_gpu);
    stitcher.stitch(imgs, pano);
    imwrite(result_name, pano);
}