I would like to perform an OBIA on high resolution UAV imagery (RGBa) of a shallow river, however I am kinda lost on how to get started.
The DN of the A-Band is 255 at each pixel, should i dump it, since it doesn’t contribute important data?
I started with LSMS to get the segmented vector file with mean and var numbers. From that I created the training and validation vectorfiles with the classes I would like to have in the end.
This training and validation vector shapefiles only needs to contain the class_id of the polygons, right? Or does it need to contain the mean and var values of the bands as well?
In my previous workflow I used segmentation (meanshift) instead of LSMS and imported mean and other values from zonal statistics result into my vectorshapefile.
Are mean and var enough or should I always use the data from zonal statistics?
Next step would be “train vector classifier”, and that’s where I got lost. As Input Vector Data I use the training vector shapefile, as validation input data the validation vector shapefile.
I extracted HaralickTexture and LocalStatisticExtraxtion from each band and some vegetation indices.
Do I need to extract texture and other features from each band separately? The resulting raster features contain even more bands, for example the Haralick Texture from red band contains 8 new bands, that would be 24 more bands in total. Or is it enough to extract them from let’s say the red band?
But those are raster data, so I cant import them as feature.
Do I have to compute ImagesStatistics for each feature? And when the answer is yes, how do I merge the different .xml files into one? I just don’t get how to use features
Last step would be VectorClassifier.
As input I use the LSMS segmentation vector result and the model file, created from train vector classifier, right? What statistic file do I use as input?
The most important is, how to use features in this process? About what do i need to be carefull?
Thanks for you help
My system: Windows10
Version of the OTB: 7.1
I installed the OTB with: download from website
QGIS version: 33.14.16