Background - Foreground - how to work on the separation?

[saint_m]

good day dear friends - good day dear gimp-experts,


hello everyone:  i am currently workin on a solution - "saving the foreground - gettin rid of the background: which approach" - you would choose here!?

i am currently working on a litte image where i want to set the lines in the foreground - free from the background.
I have to solve the task - with GIMP: Well i think that this must be possible - i could imagine that we can do this with the help and the work of some "layers" - see the image-
[url=https://preview.redd.it/saving-the-foreground-gettin-rid-of-the-background-which-v0-rnqzsjwz8zrg1.png?width=103&format=png&auto=webp&s=f3c5e2d92ec8d92e19f291cbe79923ee2d0fe400][/url]

   


hope i was able to spell out what is wanted: 

how to make clear / sure that i can save the lines (and dots) - and re-color the background - is this possible -how would you do this
which approach - you would choose here!? 

look forward to hear from you

greetings

[rich2005]

There are a few ways for this. One way to try is:

(1) Colors -> Auto -> White Balance ( the connecting lines are very faint and probably will not show on a light background)
(2) Bucket Fill using Affected Area = Fill whole selection Fill Type = FG color Mode = Color erase.
(3) Set the Background (BG) color as required.
(4) Image -> Flatten Image (this replaces any transparency with the BG color)

A 30 second animation of that: https://sendvid.com/msgycwvm

[GarzaW]

You could also try using the Select by Color or Fuzzy Select tool to quickly grab the background and delete it, leaving just the line work. It is usually the fastest way to get a clean cutout without doing everything manually.

[saint_m]

Good day dear Rich goood day dear GarzaW

many many thanks for the reply and for your input. This is much much more than expected - i am rellay ovwerwhelmed to see your suggestions , ideas and concepts of achieving the goals

I deveinitly will try out all the ways and suggested methods.

Keep up the great forum - its a awesome place to be.

[saint_m]

good evening dear GarzaW - hello dear Rich2005 


first of all many many thanks for the great reply and for your input: 



Rich you mentioned: 

There are a few ways for this. One way to try is:

Quote:(1) Colors -> Auto -> White Balance ( the connecting lines are very faint and probably will not show on a light background)
(2) Bucket Fill using Affected Area = Fill whole selection Fill Type = FG color Mode = Color erase.
(3) Set the Background (BG) color as required.
(4) Image -> Flatten Image (this replaces any transparency with the BG color)

A 30 second animation of that: https://sendvid.com/msgycwvm

[url=https://sendvid.com/msgycwvm][/url]
Well - thats just overweleming - i am so glad. 

I have tried to work according your mini-tutorial: But believe me or not:  i did not manage to get exacly to this "Screen"


i have seen the clip at least 20 times  - but i did not get it - how your steps looked exactly to achieve this screen - where we have nothing lieft than the 
line of the "Network" - 

   

hmm - probably my difficulties have to to with my "mother-tounge"  English is not my native language.. 

Well - what were the steps to achieve the screen shown above.

Now i am going to have a closer look at the clip - which is generally a true masterpiece. 

greetings 


update: aaargh - after watching the clip the 22 th time i think i have seen a small but pretty important detail:  the "mode" was set to "color-erase"

guess - that this is the important step... 

i will try it out..

[MrsP-from-C]

Did you notice the mode colour-erase in the tool settings for fill?

[saint_m]

good day dear MrsP-from-C 


first of all: many thanks for the reply - and for your input. I am glad to read your ideas. 

Quote:Did you notice the mode colour-erase in the tool settings for fill?

hmm - the modes "color-erase" - well ... afaik - the video goes way tooo fast. ITs like a fly-over that needs to go in "slow-motion" but - i cannot turn the video to this mode. 
So i have to watch it again - (and again)...
i allready started to "transkript" the steps - /(step-by-step) ...
don  t get me wrong:  i love this  video - and this method. But currently i need to get the grip - what is happening - and how to achieve the goals... 
greetings.

[WalterE]

This often happens when the background isn’t fully uniform or contains semi-transparent pixels. In cases like that, Color Erase can end up creating gaps or an incomplete result.

[saint_m]

hello and good day dear Walter - great to hear form you. MANY thanks for the reply.

btw; i am so glad to be here in the forum - its a overwhelming experience to be here - part of this awesome
community.

greetings

[saint_m]

good day - dear froemds. 


for me its helpful  if i write things down by hand or step by step, things i have to do. 

well i have made up my mind and tested some steps in doing so:  i hope that this might be helpful for others too. 



first of all: i take a screenshot of a meaningful frame from the image.
then i open the image in GIMP (File > Open).

note:  (Optional): If the image is colored, convert it to grayscale (Image > Mode > Grayscale). This simplifies edge detection.

in the next step i think its important to extract the dominant edge
therefore i need to go to the menu: Filters > Edge-Detect > Edge. 
BTW: hmm - there are other options like "Sobel" or "Laplace", but "Edge" usually gives a clean result for network structures.
Hmmm -  for the fine-tuning: If the line is too weak or too strong, we need to adjust it using Colors > Curves or Colors > Brightness/Contrast. The goal is a crisp black-and-white line network.

Result: wou now have a base layer (let's call it "Base"), which ideally looks like a white surface with a black web of lines on it.
    

Quote:+---------------------------------------+
|  Base Layer                           |
|   .-----o      .-----o                    |
|   |      \    /         |                     |
|   o       o--o       o                    |
|  / \     /    \       / \                     |
| o   o---o      o---o                    |
+---------------------------------------+

Fig. 1: our Base layer with the extracted line network.

in the next step i think it is important  to take care for the "tracing Dots and Connecting Them 

and here i have the important part - which is allways a challenge for me . . the Working with Layers and Paths

i think its important - to  open a second layer - that is imporant:  for  the creative par that starts now: On a second layer, i select specific nodes and connect them. The Paths Tool is perfect for this.

Step 3: Create a New Drawing Layer

now i create a new transparent layer above the Base layer. well i name it "My_Network".
 Important: i need to mak  sure this new layer is selected in the Layers dialog.


 see below - how it is menat: 

Quote:+---------------------------------------+
|  My_Network (Transparent)     |  <-- all my drawing goes here
+---------------------------------------+
|  Base                                 |
|   .-----o      .-----o                |
|   |      \    /          |                |   
|   o       o--o       o                |
+---------------------------------------+

Fig. 2: The layer structure. The drawing layer sits on top of the base.*