image orientation to "upright" [closed]
Hi All, I'm new to cv so pardon the noob question. I have a set of pictures of printed out slips of paper. Each paper is of the same format, ie. they have various markings that could be used for alignment. The pictures were taken with a smartphone so can be in any rotation. How can I find the correct angle of rotation to pass to imagemagick so I can rotate the image to "upright"? Any blogs/posts/code to take a look at? Something in Python, perhaps?
An example image would be useful. How do the markings look like? Maybe a simple template-matching could help or a feature-based approach. But that depends on your images. (BTW: you can of course also use OpenCV to rotate your images...)
Maybe this post can help you: http://opencv-code.com/tutorials/automatic-perspective-correction-for-quadrilateral-objects/