OpenCV 4 with Python Blueprints - Second Edition

Warping the image

We can also do the opposite of homography estimation/transformation by going from the probed scenery to the training pattern coordinates. This makes it possible for the book cover to be brought onto the frontal plane as if we were looking at it directly from above. To achieve this, we can simply take the inverse of the homography matrix to get the inverse transformation:

Hinv = cv2.linalg.inverse(H) 

However, this would map the top-left corner of the book cover to the origin of our new image, which would cut off everything to the left of and above the book cover. Instead, we want to roughly center the book cover in the new image. Thus, we need to calculate a new homography matrix.

The book cover should be roughly half of ...