12-04-2017, 04:27 PM 
(This post was last modified: 12-04-2017, 04:29 PM by rich2005.
 Edit Reason: typo
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		Why convert to a vector? What are you using, Inkscape?
As a raster image in Gimp using stock Gimp tools.
The fore ground select tool would work.
 
or
Create a path, then path to selection is not difficult.
 
Third party tools, I like the gmic plugin http://www.gmic.eu and the interactive extract filter
Left-click (green ) for foreground, right-click (red) for background https://i.imgur.com/yG5Ar41.jpg
Separates like this https://i.imgur.com/rbqWDt1.jpg (changed my checker pattern to differ from your screenshot)
	
	
	
As a raster image in Gimp using stock Gimp tools.
The fore ground select tool would work.
 or
Create a path, then path to selection is not difficult.
 Third party tools, I like the gmic plugin http://www.gmic.eu and the interactive extract filter
Left-click (green ) for foreground, right-click (red) for background https://i.imgur.com/yG5Ar41.jpg
Separates like this https://i.imgur.com/rbqWDt1.jpg (changed my checker pattern to differ from your screenshot)

