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+--- Thread: Extracting a "Dotted Network" skeleton from a glowing raster image for vector editing (/Thread-Extracting-a-Dotted-Network-skeleton-from-a-glowing-raster-image-for-vector-editing)
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Extracting a "Dotted Network" skeleton from a glowing raster image for vector editing - saint_m - 04-19-2026
good day dearGIMP-Fans,
first of all - many thanks for your great forum. i am glad to be here - to be a part of your great forum.
today i have a workflow question: i am interested in the extracting a "Dotted Network" skeleton from a glowing raster image for vector editing
the goal: I have a complex raster image (a network of dots/lines on a dark background). I want to "isolate a layer" to get a rough, clean vector skeleton (Base Layer). Later, I will use this skeleton as a foundation to build upon (a Model Layer).
my base question 1:the right tool Selection
Which is the best primary tool for this specific "extraction" step?
a) GIMP: (For curves/threshold) - i guess that this is the tool to use
b) Inkscape: (For bitmap tracing)
c) Krita: hmmm (For color-to-alpha)
My assumption is to use GIMP to kill the background and Inkscape to trace the dots to vectors. Is there a way to do this purely in one software?
the question here: Isolation Technique
How do I isolate only the brightest: lines/dots (..without dragging the "bokeh" (blurry glow) along with them?).....
- Is it better to work with Layers (e.g., subtracting a blurred layer)?
- Or is Color Decompose (HSV - Value channel) the standard approach?
- Are there specific filters (like "Edge Detect" or "Threshold") that preserve the dot structure without making them blobs?
the Question 3: The Vectorization:
When using Inkscape's Trace Bitmap, how do I prevent the scattered dots from merging together? The original image has distinct nodes, but the glow connects them. How do I tell the software to separate the "nodes" from the "edges"?
I want to keep this technology-neutral to learn all possible approaches, but I am guess that it best would be gained if i go with GIMP
to get the workflows done.
look forward to hear from you
Thanks!
saint_m
-additional: some little & tiny ASCII Graphics that illustrates the "layer--stacking" . the"Layer Stacking" concept.
the Figure 1: The Base Extraction
my goal here: i wanna remove the background glow, and keep the structure.
Quote:Code:
[Original Image: Glowing Dots + Dark BG]
|
v (Threshold & Decompose)
+---------------------------------------+
| EXTRACTED BASE LAYER |
| .-----o .-----o |
| | \ / | |
| o o--o o |
| / \ / \ / \ |
| o o---o o---o |
| (White lines, Transparent BG) |
+---------------------------------------+
Figure 2: The Model Layer (Your desired workspace)
the Goal: Lock the base, draw freely on top.
Code:
+---------------------------------------+
| MY_NETWORK (Drawing Layer) |
| (Here I add my new colors/shapes) |
+---------------------------------------+
| BASE (Reference Layer) |
| .-----o .-----o |
| | \ / | |
| o o--o o |
+---------------------------------------+
(Locked, semi-transparent)Again: what i want is - the main goal: the Extracting of a "Dotted Network" skeleton from a example image: " glowExtracting" a "Dotted Network" skeleton from a glowing raster image for vector editinging raster image for vector editing
look forward to hear from you
greetings
ps - see a example -in this illustration we see many dods - the question - how can we isolate some of them ..!?
[attachment=14375]
RE: Extracting a "Dotted Network" skeleton from a glowing raster image for vector editing - saint_m - 04-19-2026
unfortunatly i am not able to add or to edit the threadstart - so here i add some new postings with some additional thoughts
well today i have a workflow question: i am interested in the extracting a "Dotted Network" skeleton from a little example-image for vector editing
This is only a example image and i hope that were able to disucss all the necessary things - that are the
a. technique
b. methods
c. tools and pathways to go.
the goal: I have a complex raster image (a network of dots/lines on a certain background). I want to "isolate a layer" to get a rough, clean vector skeleton (Base Layer). Later, I will use this skeleton as a foundation to build upon (a Model Layer).
my base question 1:the right tool Selection
Which is the best primary tool for this specific "extraction" step?
well - what if i want to extract only the
a. darker colors - i.e. those ones that are blue or so.
well that said - if we are able to do so - if we can isolate those dots in a certain layer then we would get a certain "skeleton".
how would you do that - what is your approach here.
ps: see for another example this image: let us take for example this image to disucss the work ....
here we have different-blue shadow-colors
Edit: Image removed at OP request, maybe a copyright issue
the question is .-are we able to extract one of the blue tones - for example - are we able to gather all the dark-blue tones - to the "Working-Layer"...
which method - which approach is here aproriate!?
RE: Extracting a "Dotted Network" skeleton from a glowing raster image for vector editing - denzjos - 04-20-2026
Looking at your example, it seems impossible to isolate different shades. Many dots have been placed on top of each other, creating various color gradations (dark - light). Actually, this example should consist of multiple layers, but you want to convert this type of image into layers. It is a bit like merging different layers with different images in, for example, GIMP and saving the result as a JPG/PNG file. You cannot then convert this file back to the original layers. You would actually need a 3D image of the dots, or the dots in separate images/layers. In my opinion, there is no solution to your question.
RE: Extracting a "Dotted Network" skeleton from a glowing raster image for vector editing - saint_m - 04-20-2026
good day dear denzjos
first of all - many many thanks for the quick reply
- well this was only a demo - a simple example. i will have a closer look for a better example - where we can discuss all what is needed.
untill later the day
have a great day -
greetings
RE: Extracting a "Dotted Network" skeleton from a glowing raster image for vector editing - rich2005 - 04-20-2026
Looking at that last posted image ximage_111_ploty.png, are you using ploty-dot-com for all your images ?
It says on their web site: Upload your dataset and get a stunning, AI-generated data app in minutes, backed by Python code. So AI strikes again. To dis-assemble your images you probably need some other method to generate your charts.
Nothing is impossible with enough time and effort. Any image can be re-created by hand. The snag of course is, "time and effort".
RE: Extracting a "Dotted Network" skeleton from a glowing raster image for vector editing - saint_m - 04-20-2026
g day rich well this is only a example nothing more. I did not find anything other - but i would say - there must be millions and much much more out there.
so sorry for the bad example. I look for a better one.
btw: unfortunaltly i cannot erase the bad example in my posting
could you do this for me. i t is prettry worhtless - and i try to find an better one
RE: Extracting a "Dotted Network" skeleton from a glowing raster image for vector editing - rich2005 - 04-20-2026
(04-20-2026, 11:01 AM)saint_m Wrote: g day rich well this is only a example nothing more. I did not find anything other - but i would say - there must be millions and much much more out there.
It is not a case of the image posted. The problem is your requests are not easily fulfilled using Gimp / Inkscape / Krita.
Just to get a mass of overlapping dots separated from a mass of half visible connecting lines to try and get a centerline trace out of Inkscape is almost impossible, needs a lot of preparation for a less-than wonderful result. - that was one of your requests.
You would be better off finding some other way.
RE: Extracting a "Dotted Network" skeleton from a glowing raster image for vector editing - saint_m - 04-20-2026
btw. on the search of a better image i thought that this might be a idea.
https://science.nasa.gov/photojournal/nasas-spherex-mission-maps-water-ice-throughout-cygnus-x/
but i dunno !?`
could we discuss the options here - ( better )!?
look forward to hear from you.
btw: it should be a gplized picture - i dunno!?
what do you say. ?
RE: Extracting a "Dotted Network" skeleton from a glowing raster image for vector editing - saint_m - 04-20-2026
well i dunno if this is a exapmle to disucc the neeeds of
all i need to have is just a simple demo-graphic:
the above meintioned one - i am not sure if it works . i guess not .
cf. NASA’s SPHEREx Mission Maps Water Ice Throughout Cygnus X
An observation made by NASA’s SPHEREx shows the chemical signatures of water ice and polycyclic aromatic hydrocarbons in Cygnus X, one of the most active and turbulent regions of star birth in our Milky Way galaxy.
PIA26748
Credits: NASA/JPL-Caltech/IPAC/Hora et al.
well i think i have do to more search. Iwill do that - later teh day.
greetings
RE: Extracting a "Dotted Network" skeleton from a glowing raster image for vector editing - denzjos - 04-20-2026
(04-20-2026, 11:35 AM)saint_m Wrote: btw. on the search of a better image i thought that this might be a idea.
https://science.nasa.gov/photojournal/nasas-spherex-mission-maps-water-ice-throughout-cygnus-x/
but i dunno !?`
could we discuss the options here - ( better )!?
look forward to hear from you.
btw: it should be a gplized picture - i dunno!?
what do you say. ?
This is a completely different problem: some information: https://www.jacknicholsphoto.com/processing-a-single-shot-milky-way-photo