image rotation

[dav1988]

i should verify if a small pic, cutted out from a bigger image, was rotated of an angle from the original. can i do this by comparing the big original image with the small image obtained from the first one? how can i do?

thanks

[fmw42]

Please, always provide your IM version and platform when asking questions, since syntax may differ. Also provide your exact command line and if possible your images.

See the top-most post in this forum "IMPORTANT: Please Read This FIRST Before Posting" at http://www.imagemagick.org/discourse-se ... f=1&t=9620

For novices, see

http://www.imagemagick.org/discourse-se ... f=1&t=9620
http://www.imagemagick.org/script/comma ... essing.php
http://www.imagemagick.org/Usage/reference.html
http://www.imagemagick.org/Usage/



ImageMagick has a compare function, but in general it does not compare different sizes of the same image or rotated versions. If there is no rotation or scaling, then compare can find where a small image resides inside a larger image.

However, the compare -metric phash may do what you want if the smaller image is a scaled and rotated version of the larger image and not a subsection.

See
https://www.imagemagick.org/script/compare.php
https://www.imagemagick.org/Usage/compare/#statistics
viewtopic.php?f=4&t=24906