Re: [Gimp-user] Change background colour with GIMP 2.10.22

[Zoltán Kluik <numizmatikakz gmail com>]

Dear Liam,

Yes, the image is in RGB colour 8 bit.
What does it mean?
"to use select -> grow by 1 oe 2  pixels and then select shrink to remove
small unselected dots."  Please explain it.

However I have reduced the size of the images, and tried to attach it
(100kb is the limit), so that's why the aim what I'm writing can not seen.

   1. Coin_original.jpg --> The original image
   2. After_global_matting.jpg --> The image after Global matting. If You
   can see when I select only the coin, GIMP copied some other points and when
   I press crtl+shift+v It can see that not outside of the edge of the image
   there is some other points (not fully white)
   3. After_Global_and_Levin_matting.jpg --> the outside points of the
   edges are deleted, which is perfect, but the colour of the edge is totally
   wrong (not same as the original was, because of the selection of global
   matting).

So this is my problem. In the old GIMP this was better..

I have thousands of photos and (and continuously will have) if the
background change process takes more time than a minute / image then I need
to change to someone else.
Thank you for Your help in advance.

Zoltan

Zoltán Kluik <numizmatikakz gmail com> ezt írta (időpont: 2021. márc. 25.,
Cs, 17:24):

> Dear Liam,
>
> Yes, the image is in RGB colour 8 bit.
> What does it mean?
> "to use select -> grow by 1 oe 2  pixels and then select shrink to remove
> small unselected dots."  Please explain it.
>
> However I have reduced the size of the images, and tried to attach it. I
> hope the system can accept it.
>
>    1. Coin_original.jpg --> The original image
>    2. After_global_matting.jpg --> The image after Global matting. If You
>    can see when I select only the coin, GIMP copied some other points and when
>    I press crtl+shift+v It can see that not outside of the edge of the image
>    there is some other points (not fully white)
>    3. After_Global_and_Levin_matting.jpg --> the outside points of the
>    edges are deleted, which is perfect, but the colour of the edge is totally
>    wrong (not same as the original was, because of the selection of global
>    matting).
>
> So this is my problem. In the old GIMP this was better..
>
> I have thousands of photos and (and continuously will have) if the
> background change process takes more time than a minute / image then I need
> to change to someone else.
> Thank you for Your help in advance.
>
> Zoltan
>
>
> Liam R E Quin <liam holoweb net> ezt írta (időpont: 2021. márc. 25., Cs,
> 14:35):
>
> > On Wed, 2021-03-24 at 00:15 +0100, Zoltán Kluik via gimp-user-list
> > wrote:
> > > . Now in 2.10.22 I open a picture, using foreground
> > > selection tool, but in this version there is a motor feature where I
> > > can
> > > select Global- and Levin matting. I use both with iteration value 1.
> > > First
> > > Global is selected, coin is rounded, pressing enter, selecting the
> > > foreground with the mouse, again pressing enter. Here the problem is
> > > that
> > > under the coin where the green background’s colour was a little bit
> > > darker
> > > there are green dots.
> >
> > One approach is  to use select->grow by 1 oe 2  pixels and then select-
> > > shrink, to remove small  unselected dots.
> >
> > Is your image in 8-bit colour RGB mode? The title bar of GIMP will tell
> > you.
> >
> > Without a sample image it's hard to tell  what's going on exactly. I
> > take it you are running Linux under GNOME 3 and have 32GBytes of RAM?
> >
> > Liam
> >
> >
> >
> > --
> > Liam Quin - web slave for https://www.fromoldbooks.org/
> > IRC::ankh in full-time voluntary servitude