On Wed, Jan 25, 2017 at 11:22 AM, Moritz Lennert < mlenn...@club.worldonline.be> wrote:
> On 24/01/17 20:40, Raphael Knevels wrote: > >> Thanks for the quick response :-) >> >> The extent of my region is also the extent of my imagery-group. For >> i.segment I used as memory 10240 MB with a threshold of 0.25. >> > > That's a pretty large threshold which generally leads to > under-segmentation. You might want to start with a value closer to 0.01. > > >> In SAGA I used at first Seed Generation (Band Width of 18, but I >> also >> varied this parameter) for producing the Seed Output. The Seed Output is >> a raster with floating point values. Moreover, the Seed Output contains >> single pixels distributed over the hole area. The "space" between those >> pixels is "no data". The segmentation is then computed by Seeded Region >> Growing with the seed grid as input. >> >> "Seeds in i.segment have to be polygons not points. These polygons >> are >> represented by identical positive integer values (= IDs) in adjacent >> pixels, and they have to cover the entire region. When used as seeds for >> a segmentation, these polygons are the further merged." >> > > Sorry, but this was actually wrong information from my part: i.segment > also supports seed pixels. From the man page: > > "The seeds map can be used to provide either seed pixels (random or > selected points from which to start the segmentation process) or seed > segments. If the seeds are the results of a previous segmentation with > lower threshold, hierarchical segmentation can be performed. The different > approaches are automatically detected by the program: any pixels that have > identical seed values and are contiguous will be assigned a unique segment > ID. " > > > However, the seed map has to have integer values. To get that from you > SAGA output (floating-point) seed map, just run r.clump. > > -> alright. That means, I definitely must convert the no data values in >> the SAGA Seed Output to zero or any other integer number. >> > > No, I actually don't think this would help in any way as this would create > one big region out of all the no data pixels... > > Meanwhile, I also tried the segmentation result of SAGA Seeded Region >> Growing as Seeds for GRASS - this works... >> > > And how long did this take ? > > " You could try using the brand new i.superpixels.slic add-on to create >> superpixels which you can then use as seeds." >> -> I could successfully install and open it ("g.extension >> i.superpixels.slic", GRASS 7.2.0). >> However, when I run the tool with default settings, GRASS gives a problem >> message and finishs the process. >> > > Ok, this sounds like bug #3247 [1] for which the author hasn't applied the > fix, yet. Rashad, will you have the opportunity to apply just the fix for > the actual bug (not necessarily the other proposals in the patch), soon, or > should I do it ? > I had pushed fix for compile error ( min and max ). Is it the same error? > > Moritz > -- Regards, Rashad
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