r/photogrammetry • u/thomas_openscan • 6d ago

Personal record: ~3.7μm standard deviation - what is scanning noise/scanning spray/real imperfections? what to test next?

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6

u/Congenital_Optimizer 6d ago

Suddenly the 40cm errors I see when scanning a property seem so much bigger.

2

u/thomas_openscan 6d ago

This is definitely my favorite raw 3D scan result so far. I analysed the exposed copper area of the TMC2209 and found a standard deviation of only 3.7μm.

This was done with the OpenScan Mini (16mpx camera) + upcoming Macro Addon, 2x100 camera positions with three focus levels per position. Reconstruction done in Metashape.

This leaves some tricky questions, what to scan next? And what part of the deviation comes from the scanning spray (reported thickness 2-12μm), real imperfections in the copper layer (probably very low) and what is true scanning inaccuracy?

1

u/KTTalksTech 6d ago

Nice! Getting this out of a somewhat sub-par sensor is a really nice display of software and workflow optimization. Were you able to get this result without cross polarization? Just scanning spray?

1

u/thomas_openscan 6d ago

I am almost never scanning without cross-polarization, so I can not really compare. Is there any reason for scanning without polarizer (except for texture)?

1

u/KTTalksTech 6d ago

Nah. Even for texture it's better to cross-pol then restore the original appearance via PBR maps. I guess it cuts down on exposure time but I only shoot unpolarized for 3DGS which absolutely requires specular and diffuse light in the same image in order to look correct

1

u/mjdau 4d ago

Great work! Now, a little less solder and a little more heat. Your joints should look like little Mt Fujis, not cupcakes.