On 03/04/12 10:23, Moritz Lennert wrote:
On 02/04/12 22:03, Markus Neteler wrote:
On Mon, Apr 2, 2012 at 1:42 PM, Moritz Lennert
<mlenn...@club.worldonline.be> wrote:
...
4. Currently GRASS does not provide any image segmentation as such.
i.smap
contains image segmentation in its process, but the user cannot get
segmented outputs.
Just a small comment - even not this one?
http://grass.osgeo.org/wiki/GRASS_AddOns#r.seg
r.seg performs image segmentation and discontinuity detection (based on
the Mumford-Shah variational model).
Ah, another GRASS module I didn't know about. ;-)
Perhaps it could be extended?
I'll have a look at it.
I did a rapid test with a landsat image:
for lambda in 0.01 0.1 1 10 100
do
for alpha in 0.01 0.1 1 10 100
do
r.seg in_g=L72199024_02420020729_B80@PERMANENT
out_u=test_seg_$lambda\_$alpha out_z=test_seg_dis_$lambda\_$alpha
lambda=$lambda alpha=$alpha --o
r.colors -e map=test_seg_$lambda\_$alpha color=grey
r.colors -e map=test_seg_dis_$lambda\_$alpha color=grey
done
done
The lamba=100 and alpha=100 seems to give visually me roughly what I was
thinking of, i.e. a series of regions. However, each pixel still has a
different value and so I would have to go through more steps before I
could try to delineate actual polygons which I could then classify.
AFAIU (and this is still a bit limited) r.seg seems to be more oriented
towards visualisation than towards further treatment of identified
"segments".
Moritz
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