It actually is a bug. The guide acts from the background so it is correctly but never intended this way. If you look at erosion and dilation it is mostly described from view of the object, being letters here. If you know what you doing it is no pro lem, but for new users this is co.fusing. I have filed a bug report and will adapt documentation when I have the time.
Actually it is not really a bug, but more a way of understanding it :) If you look for erosion and dialation in books or on wikipedia, it is explained as if the object is seen as zero values... So i was mistaken there and was looking for a way to explain it more clear, thats all :)
Documentation is correct in this section! White pixels have 255 value, black ones - 0. After dilate square of black pixels should decrease, because we choose maximum in each window.
http://code.opencv.org/issues/2971 could you close down this bug issue then? Or do you still want me to add some comment on why there is a difference in explanation between Wikipedia & OpenCV docs?
Dilation and erosion work on white pixels(pixels with 1 value) so when you dilate above image you expand white area and when eroding reduce white area.
So there is not any bug!
Asked: 2013-07-09 01:37:52 -0600
Seen: 567 times
Last updated: Jul 10 '13
-----Dilate---->
Not sure if the error has been rectified or you got it all wrong :| .
Dilate -> Local Maximum. Erode -> Local Minimum.