Dear all, Thank you for your previous support and help. I am performing an image analysis and the region of interest is the area between the two lines. I was able to remove the inner part by using the invert and cut option. But I am having a hard time removing the portion from the outermost line.

I am quite new to image processing software like GIMP.

Thanks,

Highlander

One option might be the Magnetic Scissors, although the performance of that tool is not optimal.

Another way is selecting the black line with the Fuzzy Select Tool. Convert the selection into a path and then delete all the nodes of the inner path with the Paths Tool ('CTRL + Shift + Click' deletes a node).
Which leaves you with a pretty accurate path, you can use for a selection.

A third way is using G'MIC - Extract foreground.

The Quick and Easy Way.
Do you want to remove the portion between the outermost line and the image edge or frame?

If so I would use the free select tool. Trace around the outermost line again using the left mouse click in a step by step
method, then take your free select line outside the canvas and around it like the screen grab.


After you hit delete.


Removing the entry/exit on the LHS can also be done with Free Select.

Duplicate layer, make everything inside the outer line black, select the black part, invert selection, duplicate bottom layer, remove selected part form that layer by deleting the selection. That layer has now only the inside part. Delete all other layers.

instead of painting with a brush we could take advantage of the contrast between the black line and the rest of the image:

duplicate layer
with the Levels Tool, drag the white point slider to the left, until only the black line is visible
then click in the white area with the Fuzzy Select Tool
apply Layermask from (inverted) selection to the original layer
delete helper layer
touch up the layermask with a brush where the Fuzzy Select didnt catch

probably the quickest method so far, i guess

ninja'd by konstantin but some screen shots so

The gmic foreground extract works well for this type of image.

A quicker way

The saving grace for that is the black border. Duplicate the layer, Apply Threshold Colors -> Theshold with the left side slider right down to a value 1 or 2. looks like this:



That will let you fuzzy select outside the cell:



Delete the top layer, leaving the selection in place. Cut, Ctrl-X the selction (or fill with white) :

Hi there Konstantin, thank you very much! I really appreciate your help!

Hello Tas_mania, I appreciate your help, I tried your method and it works!! Great!!

Hi Vincent, thanks a bunch! Appreciate your help.

Hi Rich2005, thank you very much for all your help. I really appreciate your effort!! I tried your method and it worked!

just figured out there is an even quicker way, but you need to have ofnuts Paths tools installed:
01) select black line with fuzzy select tool
02) convert selection into path, deselect
03) in the paths tab, 'break path apart' from the right click menu, now you have two new seperate paths
04) activate selection from outer path
05) apply layermask from selection, then deselect

get ofn-path-edits here:
https://sourceforge.net/projects/gimp-p ... s/scripts/

Late in the ball game, but zoom in, use Fuzzy Select tool to select outer black line. The selection will be two dashed lines around the inside and outside of the black line. Use Select/Remove Holes. That selects the whole inside of the outer black line. Invert selection and fill with white.