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Top Student
Posts: 9
Member Since: ‎08-20-2017
Message 1 of 6 (532 Views)

Inaccuracy in scan shots alignment

[ Edited ]

Hello, 

My setup is a custom david setup consisting of a single IS 23UX236 and a computar 12mm (1214mp2)  and 16mm lens coupled with LGPF1500W. 210mm calib panel . Im scanning relatively long objects. (pieces of wood  furniture. table legs, etc) single scan quality is decent. however scans are not accurate on sides and not match on where 2 or more 3d shots meet. so usually it results in layers of 3d mesh above eachother where multiple shots overlap. I found that align sequence command results in more inaccuracy compared to manual contact pait selection. 

I'm trying find the root cause. so far i reprinted the calibration panel, and changed the projectorand replaced the lens. using computar 12mm compared to imaging source 5mp TCL lens, the deviation between scans is less, using ACER Projector (1283i) results in better projection image, but not more accuracy. I want to eliminate this deviation and distorion effect between scan shots. so I'm willing to buy a high-end lens (schneider cinegon 12mm) .  the lens is expensive, so I want to know if i change the lens would it be a big improvement in scan precision to compared to computar 1214mp2.

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Grad Student
Posts: 163
Member Since: ‎10-31-2016
Message 2 of 6 (505 Views)

Re: Inaccuracy in scan shots alignment

Check your projector settings. Keystone feature should be off and 0. Any other "help" features (that improves picture quality) should also be off. Is there any setting for projection location? Resolution should also be native, check the internet for native resolution of your projector. Seems that your scans are distorted because of projector settings. Lens distortion is compensated in calibration. Also check your calibration panel, angle between panels should be exactly 90 degrees. 

I am an HP Employee

**Views expressed are my own, no one else would say such drivel**
Top Student
Posts: 9
Member Since: ‎08-20-2017
Message 3 of 6 (493 Views)

Re: Inaccuracy in scan shots alignment

thanks for your reply, my calibration panels are made of plexi glass. here's the scan of the calibration panel and the angle between the two sides in geomagic: 

1.PNG

2.PNG

3.PNG

 

 

Top Student
Posts: 9
Member Since: ‎08-20-2017
Message 4 of 6 (477 Views)

Re: Inaccuracy in scan shots alignment

[ Edited ]

Projector is displaying@native resolution with keystone set to zero. Auto keystone off, sharpness set to 0, all projector picture enhancements set to zero. I've tried two projectors as i mentioned in first post with same results. above is my calibration panel. could it be the source of problem? I've made a second calibration panel and again the same results. calibration panel looks almost the same in geomagic. 

 

Im getting this type of distortion:

IMG_20170821_071708.jpg

 IMG_20170821_071712.jpg

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Grad Student
Posts: 163
Member Since: ‎10-31-2016
Message 5 of 6 (465 Views)

Re: Inaccuracy in scan shots alignment

Second and third picture of your calibration corner are showing that you have some kind of distorsion in scans. Usually it comes from keystone feature.You can see that outer parts of your scans are distorted and those are not aligning. That matches exactly to that what your pictures of a calibration corner are saying. Angle between panels seems to be good.  Which graphic card are you using? Can you try to use some other cam just for test purposes? I belive that cause of distortion in your scans is projector, but you can try to test all key components to see if there will be any progress. Can you try to use different computer with different gfx card maybe?

I am an HP Employee

**Views expressed are my own, no one else would say such drivel**
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Top Student
Posts: 9
Member Since: ‎08-20-2017
Message 6 of 6 (456 Views)

Re: Inaccuracy in scan shots alignment

Thanks again for your reply. I have 2 cameras (IS 23ux236, IS 33ux178, 3 lenses (Computar 12mm, Computar 16mm, Imaging source 5mp TCL lens), 2 projectors (LG PF1500W, Acer 1283i, a PC with Asus/Nvidia 1050Ti Grpahics card  and a laptop with AMD Radeon HD 7670M (PC and laptop running Windows 10 latest updates) , 2 calibration panels (Self made) and the distortion effects happen in all configuration. Keystone, auto-keystone, corner keystone is set to 0. running native resolution. 

if this is a graphics card issue, can you point me the right settings for the the projector and HP 3d (David) software to use in grphics card driver settings? 

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