Legacy ImageMagick Discussions Archive

I am puzzled why the rmse value returned from a subimage compare does not correspond to the rmse value returned by cropping the appropriate subsection and do a simple compare.






Subimage compare rmse:

compare -metric rmse -subimage-search logo.png logo_wizard_blur3.png null:
3445.01 (0.0525675) @ 327,130

Simple compare
compare -metric rmse logo.png[169x160+327+130] logo_wizard_blur3.png null:
11611.7 (0.177184)


I would have expected to get the same values. What am I missing here?

In IM 6.8.6.0, I am still getting the results as above which do not match. Is this a bug or am I misunderstanding something?

Can anyone else verify this or explain the difference?

We can reproduce the problem you posted and have a patch in ImageMagick 6.8.6-1 Beta available by sometime tomorrow. Thanks.

magick wrote:We can reproduce the problem you posted and have a patch in ImageMagick 6.8.6-1 Beta available by sometime tomorrow. Thanks.

Which one was bad -- the subimage search or the direct compare?

They both match with rmse of 11611.7 (0.177184) in the current 6.8.6.1 beta (Q16). Thanks