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How To Remove Stray Pixels On A White Background?

Nov 3, 2013, 16:58
Post: #1
Rainbow How To Remove Stray Pixels On A White Background?
Hi Gang,

I rebuilt my line on white background with help from Rich2005 and Ofnuts. My latest version is darker, smoother higher res and wider (see attached).

The problem now are stray pixels, many of them unattached to the line itself. I spent a lot of time with an eraser, but still haven't gotten them all. THERE MUST BE A BETTER WAY!

I found this excellent link on the subject. http://gimpchat.com/viewtopic.php?f=23&t=16
RobA even has a script to do what I want. However, I don't think it is GIMP 2.8 compatible, as I can't seem to find it to run it. Sad

Is the other approach mentioned by Oregonian the easiest approach? It seems this would be a pretty common problem to solve and it would be nice if there was a simpler solution...

fastcar Huh


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.xcf  beta wave to alpha wave 3200px darker thicker smoother.xcf (Size: 637.54 KB / Downloads: 39)
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Nov 3, 2013, 17:25
Post: #2
RE: How To Remove Stray Pixels On A White Background?
(Nov 3, 2013 16:58)fastcar Wrote:  I found this excellent link on the subject. http://gimpchat.com/viewtopic.php?f=23&t=16

That link is GOLD. Oregonian's process was easier than it sounded, and I got fabulous results just selecting the background followed by EDIT:CLEAR. Highly recommended. If I had found this before, I would have saved 30 minutes of tedium that still didn't give complete results (trying to chase stray pixels with an eraser). You can see how much better the line looks now in the attached.

fastcar Smile


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.xcf  beta wave to alpha wave 3200px darker thicker smoother stay pixels deleted.xcf (Size: 541.36 KB / Downloads: 31)
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Nov 3, 2013, 19:42 (This post was last modified: Nov 6, 2013 09:43 by rich2005.)
Post: #3
RE: How To Remove Stray Pixels On A White Background?
That is a very acceptable image.
Many ways of getting a result in Gimp. Have a look at Ofnuts posts on removing backgrounds.
http://gimpforums.com/thread-proper-subj...d-painting

In the meantime I did this little video, yet another way.
There might be something in there of interest or not as the case may be.

A 3 minute fix using Gimp basic tools.

having a tidy up - everyone finished with this ...going..going..gone
http://www.youtube.com/watch?v=11mVecs26kI&hd=1

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Nov 4, 2013, 09:21
Post: #4
RE: How To Remove Stray Pixels On A White Background?
(Nov 3, 2013 16:58)fastcar Wrote:  The problem now are stray pixels, many of them unattached to the line itself. I spent a lot of time with an eraser, but still haven't gotten them all. THERE MUST BE A BETTER WAY!

Maybe Inkscape should have got a mention, the trace bitmap function works almost straight off. I had to increase the brightness cutoff value to 0.9 otherwise everything default.

It pays to export from Inkscape as a bitmap (png), the anti-aliasing is better than stroking the svg path in Gimp.

Did not realise until too late there was a small version and a large version so I am sticking to the original 125 version.


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Nov 4, 2013, 14:22
Post: #5
RE: How To Remove Stray Pixels On A White Background?
(Nov 4, 2013 09:21)rich2005 Wrote:  Maybe Inkscape should have got a mention, the trace bitmap function works almost straight off. I had to increase the brightness cutoff value to 0.9 otherwise everything default.

It pays to export from Inkscape as a bitmap (png), the anti-aliasing is better than stroking the svg path in Gimp.

Did not realise until too late there was a small version and a large version so I am sticking to the original 125 version.

Rich, your output looks awesome. Did 'Inkscape' (not sure what it is) also take care of making the line thicker and darker, too, or just clean up the stray pixels?

fastcar
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Nov 4, 2013, 17:14 (This post was last modified: Dec 2, 2013 09:47 by rich2005.)
Post: #6
RE: How To Remove Stray Pixels On A White Background?
Inkscape is an open source vector graphics editor much the same as Gimp is an open source bitmap editor. They do complement each other so if you want to make a scalable logo or lettering use Inkscape but for editing a photograph use Gimp.
see: http://inkscape.org/

Easier to make another little video rather than a long winded explanation.

having a tidy up - everyone finished with this ...going..going..gone
http://www.youtube.com/watch?v=EQg75dUlHkI&hd=1 3 mins start to finish

As with all things there is a learning curve (no pun intended).

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Nov 4, 2013, 22:08
Post: #7
RE: How To Remove Stray Pixels On A White Background?
(Nov 4, 2013 17:14)rich2005 Wrote:  Inkscape is an open source vector graphics editor much the same as Gimp is an open source bitmap editor. They do complement each other so if you want to make a scalable logo or lettering use Inkscape but for editing a photograph use Gimp.
see: http://inkscape.org/

Easier to make another little video rather than a long winded explanation.

http://www.youtube.com/watch?v=EQg75dUlHkI&hd=1 3 mins start to finish

As with all things there is a learning curve (no pun intended).

Wow, a tutorial video with my own file being worked on. How cool is that! Thanks for sharing that, Rich!

Honestly, that line is even better from Incscape than the one I have now from Gimp. Seems like it was easier to make, and it has no holes or light pixels inside it as mine does right now. I would definitely look into trying that out next time. Thank you!

fastcar Smile
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