Quantify empty cells in scans

[tonisgeospace]

I would like to quantify the completeness of my scans (in order to be able to compare different scans) by determining the empty cells using the rasterize or 2dvolume tool. However, the entire dimension is always used as the reference for the determination (see image - at least that's what i assume) and therefore I have a much too high number of empty cells. My idea is to fill the empty cells of the cloud first and then throw the filled cloud and the one with the empty cells into the 2dvolume-tool and thus determine the empty cells via matching cells. Would this work and if so, how can the empty cells be interpolated?
I have attached an example of a scan of an excavation where you can see the holes that I want to quantify.

Maybe I'm just not seeing a simple problem here - if anyone can help me I would be very grateful.

Thanks in advance!

[daniel]

Can't you more simply segment the scans before hand, always with the same bounding-box? Maybe with the Cross-section tool? (you can manually input the limits of the box). You can also do that with the command line tool if you have a lot of scans (-CROP option).

At least this will allow you to always have the same grid size in the 2.5D Volume tool. And therefore get the same '100%' of completeness, as long as you use a complete cloud as reference.

Note that you can also manually set the XY boundaries of the raster in the Rasterize tool.

Other than that, closer to what you were imagining, you can 'interpolate' missing parts of a cloud with the Rasterize tool (with the 'Kriging' filling option). And then export the resulting raster as a cloud.