On Fri, Feb 3, 2017 at 3:07 PM, Moritz Lennert <mlenn...@club.worldonline.be > wrote:
> On 03/02/17 14:06, Rashad Kanavath wrote: > >> >> >> On Wed, Jan 25, 2017 at 11:22 AM, Moritz Lennert >> <mlenn...@club.worldonline.be <mailto: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? >> > > No, it was the error explained in #3247. But the issue was fixed and since > then MarkusM has significantly build upon your work on i.superpixels.slic. > We now have a nicely functioning module. Thank you for your great work on > this ! > Sorry. I saw that later. l SLICO and other options needs to be added I think. > > Moritz > -- Regards, Rashad
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