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opencvtransformationdistortionhomography

HOW TO use Homography to transform pictures in OpenCV?

I've two pictures (A and B) slightly distorted one from the other, where there are translation, rotation and scale differences between them (for example, these pictures:)

ORIGINAL LENA DISTORTED LENA

Ssoooooooo what I need is to apply a kind of transformation in pic B so it compensates the distortion/translation/rotation that exists to make both pictures with the same size, orientation and with no translation

I've already extracted the points and found the Homography, as shown bellow. But I don'know how to use the Homography to transform Mat img_B so it looks like Mat img_A. Any idea?

//-- Localize the object from img_1 in img_2
std::vector<Point2f> obj;
std::vector<Point2f> scene;

for (unsigned int i = 0; i < good_matches.size(); i++) {
    //-- Get the keypoints from the good matches
    obj.push_back(keypoints_object[good_matches[i].queryIdx].pt);
    scene.push_back(keypoints_scene[good_matches[i].trainIdx].pt);
}

Mat H = findHomography(obj, scene, CV_RANSAC);

Cheers,

Solution

  • You want the warpPerspective function. The process is analogous to the one presented in this tutorial (for affine transforms and warps)