So I set up a test rig.

sensor	real volumen
probes	signal

Then the raw data was analysed with octave.
Therefore I wrote a script that reads the file my oscilloscope writes to an USB flash drive.

raw signals

filtered signals

Finally the filtered data should create an 3D image. Which - so far - does reproduce something that looks nothing like the first image. Bummer.

What I rate as success is that the filtered data looks like I anticipated. Maybe I made a mistake with calculating the 3D volume, anyway I'll keep hacking until this works.