blending two images by Opencv

Question

I want to align two images of different sizes using Opencv, Indeed the function cvAddWeighted enables us to combine or blend two images of identical sizes which is not my case !

Answer 1

You write a Rect_from_Mat function which returns Rect(0, 0, img.rows, img.cols).

Then:

Rect roi = Rect_from_Mat(img1) & Rect_from_Mat(img2);

Mat img1_roi = img1(roi), img2_roi = img2(roi);
if(results_in_img1)
{
  addWeighted(img1_roi, alpha, img2_roi, beta, gamma, img1_roi);
  return img1;
}

Note that the 'addWeighted' line will (indirectly) overwrite img1's image data.