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RC Car Component Scan

Posted: 12 Jan 2021, 05:11
by hoffybeefe
Hi All,

Just wanted to add some scans for reference for others as its always interesting when i see others do it. :)

Here is a scan of an RC Car component. It was NOT coated at all and its just the usual black injection molded plastic. I was testing how well it would scan (if it would at all). Turned out pretty well considering IMO. And the accuracy seems to blow my mind (see screenshots).

Re: RC Car Component Scan

Posted: 12 Jan 2021, 10:27
by OBNRacerMan
Good scan.
But on each of its parts, before joining into a single model, I saw distinct bands from the desynchronization of the frequencies of the camera and the projector. You need to choose this parameter better (if the camera has the ability to accurately extrude the shutter speed). Or double the shutter speed - this usually helped against parasitic artifacts.

Re: RC Car Component Scan

Posted: 13 Jan 2021, 04:27
by hoffybeefe
Hi,

Yes i get the banding pattern a lot and i can't seem to tweak it out. Using HP3DScan, my camera doesn't "remember" the settings. Every time i go into its settings, change them, and click the "OK" button to return to HP3DScan, it just seems to reset the settings to whatever HP3DScan wants them to be regardless of what i set. Very infuriating. :(

Re: RC Car Component Scan

Posted: 13 Jan 2021, 06:24
by OBNRacerMan
hoffybeefe wrote: 13 Jan 2021, 04:27 ... it just seems to reset the settings to whatever HP3DScan wants them to be regardless of what i set. Very infuriating. :(
Have you turned on permission for HP so that it can independently store settings? Advanced Settings-->Camera-->EnableAutoPropertyHandling?

Re: RC Car Component Scan

Posted: 14 Jan 2021, 01:48
by hoffybeefe
I was really hoping the setting you listed was going to help me solve the issue but upon checking the setting it seems to have been set to 'on' all this time so it appears it doesn't help. :(

Re: RC Car Component Scan

Posted: 14 Jan 2021, 02:05
by hoffybeefe
I've tried to upload a video of the issue i'm getting.

Re: RC Car Component Scan

Posted: 14 Jan 2021, 10:11
by OBNRacerMan
hoffybeefe wrote: 14 Jan 2021, 02:05 I've tried to upload a video of the issue i'm getting.
My current cameras also do not remember all settings in David / HP. The shutter speed (I put 16667.000) is remembered, but all the time I activate sharpening in the settings (and with it the speed drops from 60 to 20fps and the quality of the scan deteriorates greatly)

P.S. However, lately I hardly use HP3DScan (since I switched to Rangevision)

Re: RC Car Component Scan

Posted: 14 Jan 2021, 10:27
by hoffybeefe
Thats interesting. Must be an anomaly of not being specifically supported i suppose. I played around a little more and figured out that if i change the explicit frame rate that that same dialog just a few rows below where i was changing the exposure time... it actually 'remembers' that frame rate setting. So i set it to 30 and the image stays perfectly stable in the view port. However there are still strange patterns in the scan, but different shapes.

I might set up my DELL M110 and try it again as i've been testing a different projector to see if it was specifically the projector causing issues. Seems like there are pattenrs whether i use either projector, they just vary slightly. So i'm not sure what is causing it.

I will do some tests soon and post some screenshots of the different patterns. Perhaps your experience may know some other settings or things i can check/change/fiddle with! ;)

Re: RC Car Component Scan

Posted: 14 Jan 2021, 12:48
by OBNRacerMan
There are a lot of reasons and options for scanning quality ... related to both software settings and hardware.
I use a low resolution projector (1280x720) so I have to put it closer to the object to get the maximum pixel density of the projection on the surface.
And then the selection of the position of the cameras relative to the projector begins. And, in my case, if I move the cameras back from the projector, I get better quality than if the cameras (with the same lenses) are moved to the front of the projector. Because the distance from the cameras to the object remains unchanged and, in fact, we can assume that only the projector is moving relative to them. But, the further the projector is from the object, the larger the pixels it produces become ... and they degrade the quality of the scan.
Left - cameras behind, right - front of the projector
Left - cameras behind, right - front of the projector

Re: RC Car Component Scan

Posted: 14 Jan 2021, 15:14
by Micr0
hoffybeefe wrote: 12 Jan 2021, 05:11 Hi All,

Just wanted to add some scans for reference for others as its always interesting when i see others do it. :)

Here is a scan of an RC Car component. It was NOT coated at all and its just the usual black injection molded plastic. I was testing how well it would scan (if it would at all). Turned out pretty well considering IMO. And the accuracy seems to blow my mind (see screenshots).
Very good scans for black plastic.
adding to what OBN said, Some of those lines would also be lessened if the surface was coated or lighter. David can scan black and somewhat shiny surfaces, but it really doesn't like to.