Basic Manual Point Cloud Filter for Better DTMs

Your DTM algo is to put it mildly, less than perfect. But no AI based filter is going to be perfect. One of the big reasons is to the best of my knowledge these filters try to identify objects to filter out based on their geometry and don’t take their color into consideration.

Now go lookup/research/try the “color replace” feature in Photoshop. You can either select an area of the image or operate on the whole image, pick a color in the image with a picker, and then adjust how narrow or wide of color range to include in the selection.

Now imagine a fairly common site image where the ground is shades of brown, and there are patches of green bushes, trees, yellow colored heavy equipment, blue/red/black cars parked, white/grey shingled or commecial roofs, etc. Take a tool like that and add it to Map view (or model view) so you can pick out color ranges and delete all of the points in the point cloud that match that color without a specified range, or be able to draw around an object (like you do for area/volume calculation) and remove EVERYTHING within that boundary from the point cloud. And add a toggle to turn on or off the AI DTM filter as a first pass filter. Results = a much more accurate DTM given the human being more control to identify the objects to be removed from the DSM.

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If you export the .obj file and read it into McNeel’s Rhino program, then this type of filtering can be easily done. You can use the free demo version of Rhino for 90 days to try this out. But you will need to learn something about Rhino and writing Python scripts to give this a go. I may be able to help you a bit with this part if you want.


Wasn’t asking how to do it. I use Metashape to do it already. I was just suggesting something simple as a feature request to DroneDeploy that would simplify the workflow in some circumstances requiring the use of only one software tool instead of a combination.

Carlson Precision 3D Topo would be a good, simple interface to emulate. There are two pieces to it with 4 values to it which can be batched but I have never seen two maps that can use the exact same settings except for getting rid of small trees and vehicles. As you get larger than that it becomes harder and harder to determine ground. Correlator 3D has an amazing DTM feature that I don’t quite understand how it is doing it because it is auto but it is on the other end of the spectrum and a little harsh.