1 Topic by pirvan

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Topic: Multiple scanning passes - Increasing the number of revolutions/scan

I had this idea that if I could tell the scanner to do multiple revolution per scan, the quality would improve, because it would get a chance to fill in spots it missed on the first pass.

To this end I thought that changing the number of degrees in the scan page, would do just that.  But it doesn't appear to do anything.  Regardless of how many degrees you tell it to do (I tried 720º & 1080º), it only makes one revolution (360º).

Is this a bug, or am I doing something wrong?

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2 Reply by elmoret

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Re: Multiple scanning passes - Increasing the number of revolutions/scan

Why would quality improve? Wouldn't it just take a series of identical pictures?

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3 Reply by pirvan

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Re: Multiple scanning passes - Increasing the number of revolutions/scan

Sometimes, and I don't know why this happens, the scanner misses or drops and entire swath, as if it skipped a few steps during the rotation.  I've watched it scan and I know it didn't skip, yet there are gaps in the final scan that I can't explain why they happen.

I was thinking that a second pass may fill in those missing parts.

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To print or, 3D print, that is the question...
SD3 printer w/too many mods,  Printrbot Simple Maker Ed.,  FormLabs Form 1+
AnyCubic Photon, Shining 3D EinScan-S & Atlas 3D scanners...
...and too much time on my hands.

4 Reply by elmoret

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Re: Multiple scanning passes - Increasing the number of revolutions/scan

I feel like it'd be better to just detect that during the scan and go repeat those angular positions.

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5 Reply by hairu526

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Re: Multiple scanning passes - Increasing the number of revolutions/scan

Hmm... I'll look into what could be causing that.

6 Reply by pirvan

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Re: Multiple scanning passes - Increasing the number of revolutions/scan

hairu526 wrote:

Hmm... I'll look into what could be causing that.

Any insights on this issue yet?

To print or, 3D print, that is the question...
SD3 printer w/too many mods,  Printrbot Simple Maker Ed.,  FormLabs Form 1+
AnyCubic Photon, Shining 3D EinScan-S & Atlas 3D scanners...
...and too much time on my hands.

7 Reply by hairu526

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Re: Multiple scanning passes - Increasing the number of revolutions/scan

I'm still looking into it.

8 Reply by hairu526

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Re: Multiple scanning passes - Increasing the number of revolutions/scan

pirvan, if you try to scan just the missing part (using the degress/range option on the SCAN page) does it pick it up?

9 Reply by pirvan

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Re: Multiple scanning passes - Increasing the number of revolutions/scan

The problem, and the missing areas, are random.  If I tried to scan the same thing again, it would probably be missing parts in other areas.

As I mentioned before, when I tried to do multiple revolutions (720° for example), it didn't do it, it only did a single revolution (360°).  However, when I told it to do only 90° worked.  But I don't know how to tell it to do a range from a specific stating point (like from 45° to 90°).  How do you input that?

FWIW, I found that the missing bands seem to get worse on larger/more complicated scans with each successive scan.  So if I power down between scans, I usually get a pretty decent scan (some missing parts. but not too bad).  But if I do 3-4 successive scans, it gets pretty bad. 

This sort of leads me to think the problem may be either with memory or resources not being released after each scan, or maybe thermally related issues?

Just thinking out loud...

To print or, 3D print, that is the question...
SD3 printer w/too many mods,  Printrbot Simple Maker Ed.,  FormLabs Form 1+
AnyCubic Photon, Shining 3D EinScan-S & Atlas 3D scanners...
...and too much time on my hands.

10 Reply by Claghorn

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Re: Multiple scanning passes - Increasing the number of revolutions/scan

pirvan wrote:

This sort of leads me to think the problem may be either with memory or resources not being released after each scan

Uninitialized variables that happen to be zero on the first run, but re-use memory with random contents on subsequent runs are always a good candidate for things like this :-).

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