Frequencies in David SLS Macro scan

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mxtar_2001
Posts: 2
Joined: 08 Jan 2019, 15:49

Frequencies in David SLS Macro scan

Post by mxtar_2001 » 14 Oct 2019, 11:10

I was creating a coin scan but not 100% satisfied with surface. I have some frequency from projector in the result that bothers me. I was changing fps relation between cam and projector as well as shutter time etc. no mayor changes somebody have a idea?
Scan_Waves.JPG

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Micr0
Posts: 363
Joined: 15 Nov 2016, 15:20

Re: Frequencies in David SLS Macro scan

Post by Micr0 » 14 Oct 2019, 15:55

mxtar_2001 wrote:
14 Oct 2019, 11:10
I was creating a coin scan but not 100% satisfied with surface. I have some frequency from projector in the result that bothers me. I was changing fps relation between cam and projector as well as shutter time etc. no mayor changes somebody have a idea?
Scan_Waves.JPG
The periodic ridges tend to be camera and projector sync and the roughness is noise (from any number of sources) in my experience. Without more information, I'd say that the roughness on your scan looks like incorrect exposure level. That said, after taking a bunch of scans and aligning them, some of it will go away when you fuse the scans together. You are getting very good detail on the coin features. Check your exposure levels and try completing a few scans to see how the fused mesh comes out. Play around with the smoothing level while fusing a see what results you get.

Let us know.
µ

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OBNRacerMan
Posts: 64
Joined: 12 Aug 2019, 09:46
Location: Obninsk, Russia

Re: Frequencies in David SLS Macro scan

Post by OBNRacerMan » 14 Oct 2019, 16:29

Did you use one or two cameras for scanning?

mxtar_2001
Posts: 2
Joined: 08 Jan 2019, 15:49

Re: Frequencies in David SLS Macro scan

Post by mxtar_2001 » 15 Oct 2019, 18:30

Thanks for the feedback so far. I think periodic sync is a topic as it is no standard hardware. Some possibility to get rid of this periodic ridges? I tried plug unplug or different racios between projector and cams and I can see no change.
What about exposure? normally sensors have some idle point in this case I think shutter timing can be longer and aperture can be lower?

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OBNRacerMan
Posts: 64
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Location: Obninsk, Russia

Re: Frequencies in David SLS Macro scan

Post by OBNRacerMan » 15 Oct 2019, 19:03

Maybe the settings in the program itself are incorrectly made?
Here is a scan made with three different settings, with the third (yellow) being scanned twice as fast as the first (green), and the second (blue) longer than the third and, at the same time, it turned out with very low quality (bands are visible):
fire_02.jpg
Three scans with different program settings
These are the settings I use after I experimentally picked them up for my hardware:
profile_custom_01.jpg
Program settings
profile_custom_01.jpg (20.95 KiB) Viewed 307 times

bigbomber
Posts: 83
Joined: 14 Dec 2017, 18:08

Re: Frequencies in David SLS Macro scan

Post by bigbomber » 19 Oct 2019, 11:11

mxtar_2001 wrote:
14 Oct 2019, 11:10
I was creating a coin scan but not 100% satisfied with surface. I have some frequency from projector in the result that bothers me. I was changing fps relation between cam and projector as well as shutter time etc. no mayor changes somebody have a idea?
Scan_Waves.JPG
It is due to your system configuration. To solve it, use both vertical and horizontal configuration for camera and projector and increase distance between camera and projector.
also increasing the contrast of cameras can help.

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