I have a raster image with lines marking lake depths. I was wondering if there is a good way to eliminate these lines. The color on either side of the lines is the same exact value, but the lines are various shades of black/grey.
example.xcf (205.6 KB)
I’m hoping to end up with the outlines of the common lake depth colors (at most there will be 3 shades of blue) so I can then CNC these to 3 different physical depths.
If the lines are not too close to each other you can use a median blur:
Otherwise, in places like the vicinity of the 2.5 mark at the bottom there is no blue…
Bonjour,
A quick test on your image with G’MIC GIMP QT
This is simply an example and there is surely better.
Code:
to_rgba
+replace_color 30%,0,100,100,100,255,0,0,0,0
replace_color. 10%,0,124,147,172,255,0,0,0,0
replace_color. 5%,0,136,169,203,255,0,0,0,0
dilate_circ.. 20
erode_circ.. 20
blend alpha
dilate_circ 2
erode_circ 2
Bonjour!
Wow, that looks perfect! I was thinking of learning pythonfu for gimp, but this already looks perfect. I’ll see if I can reproduce your instructions. And then I’ll try expanding to delete the numbers which may work very similarly.
To find more about G’MIC commands which can also be used in the GIMP plug-in there is PDF documentation:
G’MIC The Handbook
replace_color page 462
dilate_circ page 168
erode_circ page 205
blend pages 85/86
:o)
Thank you so much!
This is actually PERFECT! I am on a Mac, so I used homebrew to install gmic CLI. And this pdf you shared explains things like the + prepending (page 6) and gives examples of the tools as CLI examples. (I was starting to look at Basics)
(Need to figure out the . and … you have in a few lines)
From Page 6 or so:
"Command selections [-1], [-2] and [-3] are so often used they have their own shortcuts,respectively ., … and … For instance, command blur… is equivalent to blur[-2].These shortcuts work also when specifying command arguments.
Code:
to_rgba # image in mode RGBA
+replace_color 30%,0,100,100,100,255,0,0,0,0 # image origine and + = new image with replace color
# 2 images : [-2] or .. = image RGBA / [-1] or . = image with replace color
replace_color. 10%,0,124,147,172,255,0,0,0,0 # image [-1] or . with new replace color
replace_color. 5%,0,136,169,203,255,0,0,0,0 # image [-1] or . with new replace color
dilate_circ.. 20 # dilate image [-2] or ..
erode_circ.. 20 # erode image [-2] or ..
blend alpha # blend the 2 images
dilate_circ 2 # dilate image
erode_circ 2 # erode image
Thanks @gstalnaker for the info about the list, and @samj for comments on the code. I got it to run at the CLI by just adding each line to the one CLI command. I’m assuming there is probably a way to put the code into a file and use the file as the commands for the CLI though. I’ll keep reading.
Again, love the output. It worked very well for this overall question I had! And love learning about a new image processing tool like G’mic! Added to the tool chest for sure.
Bonjour,
Here are a few command lines for G’MIC.
The files are in the ‘test_eradicatore.zip’ archive (at the end of this message).
To update G’MIC CLI
gmic update
To see the image
gmic i example.png
To see the effect of the filter on the image
gmic m a.gmic i example.png eradicatore_eliminate_lines
To see the original image and the effect of the filter
gmic m a.gmic i example.png +eradicatore_eliminate_lines
To export the result in PNG
gmic m a.gmic i example.png eradicatore_eliminate_lines o without_lines.png
To add options and export the result to PNG
gmic m a.gmic i example.png eradicatore_eliminate_lines pow 1.3 cut 0,255 o without_lines_pow.png
To see the original image, the effect and the options
gmic m a.gmic i example.png +eradicatore_eliminate_lines +pow. 1.3 cut. 0,255
file ‘a.gmic’
eradicatore_eliminate_lines : # The name of the filter
to_rgba # image in mode RGBA
+replace_color 30%,0,100,100,100,255,0,0,0,0 # image origine and + = new image with replace color
# 2 images : [-2] or .. = image RGBA / [-1] or . = image with replace color
replace_color. 10%,0,124,147,172,255,0,0,0,0 # image [-1] or . with new replace color
replace_color. 5%,0,136,169,203,255,0,0,0,0 # image [-1] or . with new replace color
dilate_circ.. 20 # dilate image [-2] or ..
erode_circ.. 20 # erode image [-2] or ..
blend alpha # blend the 2 images
dilate_circ 2 # dilate image
erode_circ 2 # erode image
test_eradicatore.zip (204.7 KB)
Ah, nice. So if you add code to a module file, and bundle it as a filter with a (funcition/procedure) name line, then you can use it. This is great! Thanks again!
…to delete the numbers…
From the initial code it is possible to add this line:
replace_color. 20%,0,22,0,245,255,0,0,0,0
to obtain this code:
to_rgba
+replace_color 30%,0,100,100,100,255,0,0,0,0
replace_color. 10%,0,124,147,172,255,0,0,0,0
replace_color. 5%,0,136,169,203,255,0,0,0,0
replace_color. 20%,0,22,0,245,255,0,0,0,0
dilate_circ.. 20
erode_circ.. 20
blend alpha
dilate_circ 2
erode_circ 2
It is always possible to obtain a better result, for example, by adding others ‘replace_color’ at the end of the code.
This is the best I can do using only color replacements.
A new code :
to_rgba
+dilate_circ 30
erode_circ. 30
replace_color. 10%,0,152,197,242,255,0,0,0,0
replace_color. 90%,0,255,255,255,255,114,182,239,255
replace_color. 0,0,0,0,0,0,152,197,242,255
replace_color.. 30%,0,92,95,98,255,0,0,0,0
replace_color.. 10%,0,133,164,196,255,0,0,0,0
replace_color.. 10%,0,120,143,166,255,0,0,0,0
replace_color.. 60%,0,22,0,245,255,0,0,0,0
rv
blend alpha
dilate_circ 2
erode_circ 2
:o)
Wow! That’s (again) amazing. Thanks so much for sharing that and this whole thread introduction to gmic. This will be perfect for my CNC project to cut each of these colors to a depth and paint them. I was going to laser etch the roads.
These codes are not perfect.
There will surely be corrections to be made before using the CNC, for example with the last code:
I added a filter ‘Topographie …’ in G’MIC GIMP QT which partially processs the original image and some rendering of the site https://www.gpsnauticalcharts.com/
