Author: David Mládek
Licensed under the GPLv3.
Advanced edge detection - GIMP plugin implementing Canny filter for edge searching.

Download source: https://github.com/mladedav/canny-edge- ... imp-plugin

In menu GIMP: Filters/Edge-Detect/Canny edge detection

From the documentation (translation from Czech to English using Google translate):

The plugin works on grayscale images, but can convert both RGB and INDEXED images to GRAY alone, and then perform its function.
The plugin is not yet able to work with images that have an alpha channel.

The plugin can interact interactively by filling in the "High Threshold" and "Low Threshold" values, which determine how thick edges will eventually remain in the image
(higher values ​​mean less tolerance). The values ​​can be any number from 1 to 255, if the lower threshold is higher than the upper threshold,
the upper threshold will be set to the same value as the lower threshold. Any values ​​entered should not cause unexpected behavior or failure. Preview is also available in interactive mode.

It can also work non-interactively, where five parameters are passed, and the last two are the same as in interactive mode. Again, the same values ​​are expected,
but they are not checked, and anyone who creates scripts with non-interactive calls should know the calling convention and restrictions in advance.

Nidhogg pointed to the possibility of using Canne in the thread about the Kirlian effect. Thanks for the solution.
viewtopic.php?f=11&t=18002&p=247339#p247336
Lylejk requested a version for Windows - so I compiled (32/64 bit for Gimp 2.10.14)

Edit 14-02-2020
Attention.
The 64bit version does not work properly (there is a problem with scroll bars and enlarging the window size for the preview) - sorry but I don't know why.

Thanks for the Windows version MareroQ.

Thanks, Mario. Works great. This one's on the tithonia capture I did a few years back. Have to experiment more, but am quite impressed and see its application for masks (which I need for other things such as mosaics).

Quite good given the image. Just wondering why it missed half the horizon while at the same time detecting the edges of the wake.

Because you didn't play with the threshold. Low threshold 53, high threshold 63.

I have problems with the plug-in crashing. This is caused by using the scroll bars in the preview window to pan the preview. Occasionally also caused by resizing the preview window, but the scroll bars are much worse.
Window 10
Gimp 2.10.12

Hi Blighty.

I am sorry that there are problems (I do not know if this is a problem in the code or the build environment or Gimp version).
This was a standard build without any code change (except in the menu location).
Can you confirm this for both versions (32 and 64 bit - because it was compiled in a different msys2 environment).
Does setting the window size without preview enabled help?

Ah, nice....

Did some more testing.

32 bit on Win 10 64 bit:
preview scroll bars - no problem
preview resize window - no problem
threshold - crashed once while playing, could not repeat

64 bit on Win 10 64 bit:
preview scroll bars - crashes regularly after 5th or 6th scroll
preview resize window - crashes on occasion, difficult to repeat
threshold - no problem

Yeah; mine did crash a few times; if you don't scroll, you usually don't get a crash. May try the 32-bit version later (why not; don't think there would be a penalty for doing so; lol).

lylejk
I tried today but often crash when i change settings,so i gave up.

For the test, I rebuilt the new msys2 environment with Gimp 2.10.15 and compiled Canny. This did not solve the problem.

I wanted to try the option of using Canny in the Diego's Filling scripts plugin - I looked at PDB canny ... and was surprised.

I'm not an coder but it's easy to see that there are errors in the code.

Following only logic I tried to fix it.
For brave testers Ver.0.2

Thanks.
Is the exe installable on Windows? I ask because on the sources it's written "do not install on Windows".

Well, just installed. It runs.
Thanks.

Hi Diego.

The GPL license requires a source file (* .c) so some users will also put it in the plug-ins directory and this is the first step to trouble - hence the note (do not install for Windows source file "canny.c").

Thanks for the test.

So you don't put the canny.c file in? I just put the 64 bit plugin and it still crashed if I played with the settings too long. Works if I dont but then I can't get a good result

SallyAnne, I suppose you get a crash when modifying the settings using the ^ (or the opposite) and letting the filter scale the value by 1 continuously up to the desired value.
If you instead replace each value by a new value entered directly by yourself, it should work (at least I did it repeatedly and no crash).

Sallyanne, I love your image in post 13. It is really very nice.