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Honor Student
Posts: 3
Member Since: ‎03-20-2017
Message 1 of 18 (2,145 Views)

Waves in scanns

Product Name: David SLS-3
Operating System: Microsoft Windows 10 (64-bit)

I'm having trouble with waves, slicing, patterns in my scans I have tried all the recommended fixes I have found. Any ideas? I'm using a new standard David SLS-3 with V5.1 software and a second David camera. I'm new to David and currently use photogrammetry and IR rangefinder systems to do my captures.

wavy soccer ball.jpg

To solve the wave issue I have tried 3 different computers, 2 different projectors, tried all combinations of projector frequency, camera frame rates, camera exposure, have no problems with calibration.

 

The scans look mostly fine with the texture on this phenomenon is seems more pronounced on curved objects and sometimes at certain light levels.

 thanks, any help greatly appreciated

Carl Geiger

wavy carl.jpg

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Grad Student
Posts: 219
Member Since: ‎10-31-2016
Message 2 of 18 (2,021 Views)

Re: Waves in scanns

Are you scanning in a dark room? If no, please try. Turn all lights off and avoid sunlight.

I am an HP Employee

Original David Team Member
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Tutor
Posts: 11
Member Since: ‎01-09-2017
Message 3 of 18 (1,861 Views)

Re: Waves in scanns

Here in some posts there were mentioned that there are no lines in scans with the original david/hp hardware. It is not so at all: look to the picture from the HP 3d Scan product page:3DscannerFastScanning_tcm245_2355247_tcm245_2355248_tcm245-2355247.jpg

I've marked lines here.

Top Student
Posts: 5
Member Since: ‎05-23-2017
Message 4 of 18 (1,485 Views)

Re: Waves in scanns

Hi,

 

are the sine waves in the scanner control window topped off?

 

May be you can make a screenshot of that particular window and post it here.

Honor Student
Posts: 3
Member Since: ‎03-20-2017
Message 5 of 18 (1,475 Views)

Re: Waves in scanns

I do my 3D scans in a dark room but have tried many different lighting conditions.  

 

i have tried different exposures and video clipping is not a contributing factor.

 

I have tried many different advanced settings.  

Minwavelength setting is the only one that has any noticable effect on the waves.

 

Below: Scans, different settings for MinWaveLength LtoR 12, 24, 48.

 

minwavelength l-r 12 24 48

 

very frustrated, using this scanner requires too much work to clean up the scans to be useful for my needs.  Wish it worked because photogramity has many challenges as well.

carl

Intern
Posts: 49
Member Since: ‎11-04-2016
Message 6 of 18 (1,468 Views)

Re: Waves in scanns

[ Edited ]

There are numerous threads in the old David forum devoted to waves in scans.

 
Have a look. It does unfortunately take a lot of time to go through it.
 
To sum up some of my experience:
 
Start with 60hz on projector, 1/60 on camera, then fine tune:
Adjust frequency on camera to have the less possible waves moving through the screen in live view.
Adjust frequency of projector using graphic card if possible to better fine tune the adjustment.
If using Acer K132 (or 135), do not use at full brightness (my personal experience).
Start by scanning still items with a mat surface
 
You will see incredible results on the old forum for many users.
 
Jeff
P.S. Some waves will be removed by the fusion step
Grad Student
Posts: 219
Member Since: ‎10-31-2016
Message 7 of 18 (1,448 Views)

Re: Waves in scanns

Hi Carl,

 

can you please try to make a small experiment. Uninstall gfx card driver and use windows generic driver for your gfx card.

I am an HP Employee

Original David Team Member
Tutor
Posts: 18
Member Since: ‎02-12-2017
Message 8 of 18 (1,305 Views)

Re: Waves in scanns

about wavy scan: as you scanned a human face, I can guess the object (face) is not completely static and stable during scanning process.

if you have this problem on other object, try other combination of resolution for your camera and projector. For first step, set your cam to highest res and change your projector resolution. also frequency of projector and cam should set to 1/60 sec.

 

in first topic you talk about "photogrammetry and IR rangefinder systems to do my captures", Can I know more about these systems?

Honor Student
Posts: 3
Member Since: ‎03-20-2017
Message 9 of 18 (1,239 Views)

Re: Waves in scanns

i have waves even with static items such as the soccer ball example.  camera and projector are both at 1/60 plus i have tried many other combinations.     i have tried various de-focus of projector but not much defocus of camera.     Thanks for the advice, i will try defocus of camera.

 

Carl

 

  photogrammetry: Many pictures from different angles, 123d catch, Autodesk remake, Agisoft PhotoScan

IR rangefinder: such as Occipital Structure Sensor

Tutor
Posts: 18
Member Since: ‎02-12-2017
Message 10 of 18 (1,224 Views)

Re: Waves in scanns

Hi

So try various brightness and  contrast ratio. what about lens? wide angle??

 

send a screnshot of your software window.

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