Heads...(Threshold fun).

[trandoductin]

ofnuts thought it was cool so i post it here too.

[Ofnuts]

(09-20-2018, 10:04 PM)trandoductin Wrote: ofnuts thought it was cool so i post it here too.

Ofnuts also thought you should clean-up the lines. Left to right:

• Original
  
• Color-select black, Select>To path , Select> from path, add white layer, bucket-fill. The trick is to increase the selection threshold while watching the historgram, and increase the threshold until your selection includes pixels that are in the 120-130 range, so that your selection really split the grays 50/50.
  
• Same as above, with some manual editing of the path to remove the more blatant spikes and dents
  

   

I admit that this method removes some detail around the eyes, but you can erase the eyes part of the new layer to have the previous layer see through.

[Espermaschine]

(09-20-2018, 10:04 PM)trandoductin Wrote: ofnuts thought it was cool so i post it here too.

where does he say that ? (link please)

(09-22-2018, 09:29 AM)Ofnuts Wrote: The trick is to increase the selection threshold while watching the historgram, and increase the threshold until your selection includes pixels that are in the 120-130 range, so that your selection really split the grays 50/50.

Whats the selection threshold ???
Are you working with the Threshold Tool here ? Tweaking the antialiasing or what ?
I dont understand what you are doing....

[Ofnuts]

1) On reddit: https://old.reddit.com/r/GIMP/comments/9...shold_fun/

2) The threshold setting of the "By Color select" tool. If you keep it small, the selection selects almost no edge pixels, and the result path is off by one pixel (which is quite visible since it can make small things disappear or instead be inflated)

[Espermaschine]

(09-22-2018, 11:13 AM)Ofnuts Wrote: 1) On reddit: https://old.reddit.com/r/GIMP/comments/9...shold_fun/

oh you guys conspire on reddit  

Quote:2) The threshold setting of the "By Color select" tool. If you keep it small, the selection selects almost no edge pixels, and the result path is off by one pixel (which is quite visible since it can make small things disappear or instead be inflated)

okay...so you make the selection with the Histogram window open, adjust and watch the Histogram change until it hits the middle (128), right ?
and this action splits the grays 50/50...why is that something we want ?

isnt the cleanup phase done by the conversion to path (which is really some kind of inaccuracy of the selection to path process) ?

[Ofnuts]

(09-22-2018, 11:27 AM)Espermaschine Wrote: okay...so you make the selection with the Histogram window open, adjust and watch the Histogram change until it hits the middle (128), right ?
and this action splits the grays 50/50...why is that something we want ?selection to path process) ?

Try this:

• Use a black on white image (circle selection, or text)
  
• Color-Select black with a low threshold (15 or less). Note in passing that the selection contains only very dark pixels (max value around 40). Select->To path (rename the path)
  
• Color-Select black with a threshold sufficient to include some pixels above. Select->To path (rename the path)
  
• Make both paths visible: they are different
  
• For each path, Select>To path and bucket-fil with black, set to Difference mode to compare with initial imagel
  

See attached image:
  ThresholdForPath.xcfgz (Size: 48.88 KB / Downloads: 297)

(09-22-2018, 11:27 AM)Espermaschine Wrote: isnt the cleanup phase done by the conversion to path (which is really some kind of inaccuracy of the selection to path process) ?

Yes, the path algorithm filters out the small details.

[Espermaschine]

(09-22-2018, 01:28 PM)Ofnuts Wrote: Try this:

I do understand they are different, but what is the benefit ?

It does not seem to help with cleaning up the lines.

[trandoductin]

great cleaning up ofnuts!
Esper... yeah it's all a big conspiracy on reddit heheh

[Espermaschine]

(09-22-2018, 02:30 PM)trandoductin Wrote: Esper... yeah it's all a big conspiracy

it really isnt, i just avoid the Gimp subreddit

[Ofnuts]

(09-22-2018, 01:52 PM)Espermaschine Wrote:

(09-22-2018, 01:28 PM)Ofnuts Wrote: Try this:

I do understand they are different, but what is the benefit ?

It does not seem to help with cleaning up the lines.

Using the large threshold you get  a path which is closer to the original image.