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Image segmentation questions

Question asked by rspellcdfw on Sep 6, 2018
Latest reply on Sep 7, 2018 by rspellcdfw

I have segmented an image in ArcGIS Pro using the Segmentation tool under Image Classification.  I now want to convert the image segments to polygons with the Raster to Polygon tool.  I have several questions about segmentation before I convert it to polygons.

 

1.   When there is a single pixel that is connected diagonally to a larger cluster of pixels and the single pixel and the pixels in the larger cluster all have the same value, does that mean they are all part of a single segment? In other words, can a segment extend to diagonally neighboring pixels?   

 

2.  What does the Value field in the segmented image represent?  I initially assumed it was a unique segment ID, but now I am seeing multiple, spatially separated clusters with the same value.   

 

3.  When you convert the segmented image to polygons with the Raster to Polygon tool, what field should be used to assign values from the cells in the input raster to the polygons in the output polygon feature class?  I had hoped there would be a field representing a unique segment ID that could be passed from the segmented image to the polygons.  But that doesn't seem to be the case, unless I'm missing something.   I tried using ObjectID, but got an error message (ERROR 000861 that said Field type is not valid).  And there doesn't seem to be any point in using the Value field since it doesn't appear to be unique for each segment.      

 

3.  When I segment my image (a 3 band image), the output is a 3 band image where the corresponding pixels in each output band have the same value.  Why does the Segmentation tool produce a 3 band output image where each band is exactly the same?  Shouldn't it produce a one band image where each cluster of similar pixels has a unique id?  

 

Thanks for any help,

Ruth

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