I'm trying to stitching images which are some screenshots of a long webpage scrolled from top to bpttom (also contain the browser titlebar at top of them and windows taskbar at bottom of them). Since they are plane and their overlap areas are totally identical, according to this question (http://answers.opencv.org/question/96464/simple-image-stitching-c/) , phase correlation is a proper method. I tried the phasecorrelate method (https://docs.opencv.org/2.4/modules/imgproc/doc/motion_analysis_and_object_tracking.html#phasecorrelate) and it works fine. But to stitch them, I also have to know the initial or final positions of the overlap areas. How to accomplish that? I'm new to OpenCV, so maybe my question is silly. Thanks for your help.
More detail:
Every 2 images are consist of 4 parts, and the height of every part is unknown. Part C of Img1 is totally identical with part C of img2, and the position of part C is what I want to know.
img1:
AAAAA
BBBBB
BBBBB
BBBBB
BBBBB
CCCCC
CCCCC
DDDDD
img2:
AAAAA
CCCCC
CCCCC
EEEEE
EEEEE
EEEEE
EEEEE
DDDDD