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Ripples ripples ripples......

Problems, solutions and discussion about scanning with a video projector and stripe patterns.

Ripples ripples ripples......

Postby Dodge1959 » Sat Jan 23, 2016 12:52 pm

Scans without ripples? Is this Rocket Science?
Hi guys,
I bought the complete DAVID SCANNER some two years back, but use it very little, partly because of very irregular results in scans. ;-(. I do milling of large scale objects using a 4000mmx2000mmx2000mm MACH controlled 4 axis miller, which I built myself, milling mainly on polistirene.
See some results at https://www.facebook.com/Cosas3D
A case in hand: yesterday, I scanned a toy dog with reasonable results in terms of ripples, and today, with the same settings in David (Brightness 87, Number of patterns 27 (Quality). Smooth Average 1, Smooth Mean 1, Quality Check 0.5, Exposure 1/60) , same distance between object and scanner, and no tweaking of Advanced Settings, and the results are strikingly different, and its verrrry frustrating…..Attached Screen Shot, above in purple today´s scan, below in light blue yesterdays scan.
I calibrated again this morning, and upon seeing those inacceptable ripples, varied all those settings to see if any modifications in settings would improve results, with zero luck.
I read your wonderful entries here, I see some AMAZING scans, and honestly feel overwhelmed, reading about settings I didnt even know exist never mind knowing how to change them or what that may end up doing, now I believe one has to be a rocket scientist to get consistent results.
Has anybody got any fairly easy answer to this???
Really, I think it’s a great product in terms of price and quality, but is beyond the average user who needs a decent, not perfect, .stl file, as in my case..

Frank Norton
http://www.franknorton.com
Attachments
Ripples_.jpg
Todays scan with ripples along-side yesterdays scan with much less ripples.
Dodge1959
 
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Re: Ripples ripples ripples......

Postby Curiousjeff » Sun Jan 24, 2016 6:51 pm

I don't know what projector or camera you are using, but I would check first that you are using the native resolution of the projector and set to 60Hz.

drndadoo suggested to connect the various devices on different electrical outlets to see if this is due to electric interference.

I had similar irregular results with the same setup from day to day with the Canon 60D in live view. I attributed it to "chance" depending how the projector and camera were syncing.

I don't know if this applies to David camera.

Let us know how it goes.

Jeff
Panasonic GH4 4K with lens 12-35, Inogeni 4K to USB3 hdmi capture device, projectors: Acer K135/Acer K11/NEC V260X, Canon 60D, macro 60 mm, MagicLantern
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Re: Ripples ripples ripples......

Postby Dodge1959 » Sun Jan 24, 2016 7:02 pm

Thanks Jeff,
As for camera and projector type and models, I will check tomorrow, I have all the equipment in my workshop.
And presumably I will be able to check that resolution, although I dont recall where one sets its configuration.

Thanks!!!
Frank.
Dodge1959
 
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Re: Ripples ripples ripples......

Postby Curiousjeff » Sun Jan 24, 2016 8:40 pm

This is a Windows setting.

Right click anywhere on empty place on the Windows desktop. You should then have a option to go set the resolution ( could alo appears as the video card software from Nvidia or ATI). From there you must look for the resolution of the second monitor (the projector)
Panasonic GH4 4K with lens 12-35, Inogeni 4K to USB3 hdmi capture device, projectors: Acer K135/Acer K11/NEC V260X, Canon 60D, macro 60 mm, MagicLantern
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Re: Ripples ripples ripples......

Postby Dodge1959 » Mon Jan 25, 2016 3:08 pm

Hiya Jeff,
Thanks again, did what you advised, and I can now report some improvements ;- )
I looked for the resolution settings as you instructed, but its in pixels not hertz, but played round with it and notice improvement in the ripples, not gone altogether but much less evident.
In the Configuration tab, visible upon right clicking any open space on the screen as you said, I did the following changes:
1) For the top scan in the screen shot, resolution was 1280X1024 in PC monitor, and 640X480 in projector. Too many ripples.
2) For the middle scan, I equaled the resolutions in pc monitor and projector, both at the 1280x1024 figure. Improvements noticeable.
3) In the bottom scan, I raised the projector resolution to above the PC monitor one, that is, different values; PC monitor at 1280X1024 and projector at 1680x1050 , the maximum setting in each case. Maybe its subjective, but even less ripples here.

So, is that 60 Hz setting something else I should check???? There are still some ripples, and if I compare with some exquisite scans I´ve seen on the Forum, I still have loads of room for improvement.
My equipment is standard David stuff;
Camera: DAVID CAM 3M with COMPUTAR 12 mm lense.
Projectro; ACER K11 LED projector model number DSV0920.

Regards, and thanks again, us new-be´s need guys like you round to point the way ;-)
Attachments
RIPPLES_3 different RESOLUTIONS.jpg
Dodge1959
 
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Re: Ripples ripples ripples......

Postby Curiousjeff » Mon Jan 25, 2016 6:14 pm

The pc monitor has no influence on the scanning process.

A quick Internet search shows that the native resolution of the K11 is 856 by 600 pixels.

That's the resolution you should try.

Each graphic card manufacturer has a different interface for setting frequency and resolution. You must search the web for instructions on that.

Did you try plugging the projector from a different power outlet?

Jeff
Panasonic GH4 4K with lens 12-35, Inogeni 4K to USB3 hdmi capture device, projectors: Acer K135/Acer K11/NEC V260X, Canon 60D, macro 60 mm, MagicLantern
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Re: Ripples ripples ripples......

Postby Dodge1959 » Mon Jan 25, 2016 6:20 pm

Thanks Jeff,

more tests tomorrow.

Frank.
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Re: Ripples ripples ripples......

Postby drndadoo » Wed Jan 27, 2016 11:39 am

Hi Dodge1959,

can you check please that keystone correction is turned off (value 0).
You can find K11 user´s manual page 13, here:
http://www.projectorcentral.com/pdf/pro ... l_5573.pdf
Also your environment light should be constant (not flickering), best set it off.

Hope this helps :)
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DAVID Support
 
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Re: Ripples ripples ripples......

Postby Dodge1959 » Wed Jan 27, 2016 12:25 pm

Hi Drndaoo,

thanks!I will check ketstone this morning.

When you say about environment light "best set it off" do you mean turn it off or is it a setting within DAVID?

Thanks,

Frank
Dodge1959
 
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Re: Ripples ripples ripples......

Postby Curiousjeff » Wed Jan 27, 2016 2:37 pm

He is taking about the other lights that are on in the room.

Start with all lights off.
Panasonic GH4 4K with lens 12-35, Inogeni 4K to USB3 hdmi capture device, projectors: Acer K135/Acer K11/NEC V260X, Canon 60D, macro 60 mm, MagicLantern
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Re: Ripples ripples ripples......

Postby Dodge1959 » Thu Jan 28, 2016 12:10 pm

Hi!
Thanks to both Jeff and Drndoo, I think finally the ripples problem is solved ;- )
I checked the 60Hz setting on the projector, it was good, and then whether the Auto Keystone setting was OFF. In fact it was ON , but turning it off made no improvement. But then varying the Manual Autokeystone setting from -33 to 0, made a HUGE improvement!
So I did various tests, changing the settings within the ACER projector for FREQUENCY, TRACKING and MANUAL KEYSTONE , one at a time obviously, to discover that only the manual keystone setting had any effect on ripples, and voila!...at -4 (it had been at -33) I did another scan, and there were no apparent ripples! Changing to a positive value, +30, by the way, also created ripples.
This for me is a great improvement. Most (but strangely not all) scans I´ve done in nearly two years had ripples.

By the way. I noticed something that perplexes me. I had left the calibration scale in place behind the toy dog I was scanning. I would then removed it when cleaning up. But I noticed that its scanned image did not show the white board to be flat, but rather distorted, its outer edges are curved not straight . I cant understand this. Surely the scanner should represent it as it is, 2 flat boards at right angles to each other.
Doesn’t this mean that any object that is scanned will suffer from a similar distortion? Is it (too far ) distance from the camera that causes it? Anyone any ideas?
Attached screenshots of the dog with and without ripples, and 4 screenshots of the calibration board from different angles to show the curve.

Regards and thanks for all,

Frank.
https://www.facebook.com/Cosas3D/
http://www.franknorton.com
Attachments
No Ripples!.jpg
No ripples!
2016-01-28_10-54-33.png
Screen board_1
2016-01-28_10-55-07.png
Screen board_2
Dodge1959
 
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Re: Ripples ripples ripples......

Postby micr0 » Thu Jan 28, 2016 4:08 pm

The scan of the calibration panels should show them as completely flat. Your keystone setting should be at 0. if there is any keystoneing then I would suspect that this is what is causing the warping.

µ
µ
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Re: Ripples ripples ripples......

Postby Dodge1959 » Thu Jan 28, 2016 5:37 pm

Thanks Micro!

Will check out tomorrow and get back.

Frank
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Re: Ripples ripples ripples......

Postby drndadoo » Fri Jan 29, 2016 4:30 pm

Good to see that you made improvement.
The keystone should always be off and manual value should be 0.
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Re: Ripples ripples ripples......

Postby Dodge1959 » Sat Jan 30, 2016 11:02 am

Hi Micro, Jeff, and Drndadoo,

As you can see, ripples now seem a thing of the past;-) Many thanx.

Part of my learning curve has been to discover something so basic and simple as how to changeprojector settings...and their importance.

Yeah, its in the manual...."Be sure to switch Aurokeystone Off, and set manual keystone to 0"..Thanks for all your patience. I naively asumed that somehow the ACER projector settings would by default be what they should be.

Attached a screen shot, probably one of my best scans so far. If I were a dog, I´d be wagging my tail.

There are still minor issues to be addressed, one is an area where the different geometries dont coincide/overlap...one seems higher or not in the same plane as its neighbour scan. This causes a ridge when I fuse, as David joins one to the other, seen here on the back inner right hand leg of the dog. I will try tweaking different Alignment settings.

Again, thanks...

Frank
Attachments
2016-01-30_10-44-40.png
My most ripple-free scan to date!
2016-01-29_16-31-55.png
Alignment not complete_different planes
2016-01-30_10-44-24.png
Ridge after Fuse due to incomplete alignment?
Dodge1959
 
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