Alignment problems

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3dxcan
Posts: 74
Joined: 02 Jun 2017, 17:21

Alignment problems

Post by 3dxcan » 04 Aug 2017, 13:00

My scans don't matchup on large parts. I have a wood carving of a leg of table. The scanner calibrated without a problem and Individal scans look good however they don't match after alignment. For example One side of single shot aligns well but the other side has sth like 1 mm or more gap to the next one.

What do you suggest to narrow down on the cause of the problem?

3dxcan
Posts: 74
Joined: 02 Jun 2017, 17:21

Re: Alignment problems

Post by 3dxcan » 04 Aug 2017, 13:17

I noticed the picture from the projector looks like this in phone camera image. Is this natural?

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Micr0
Posts: 281
Joined: 15 Nov 2016, 15:20

Re: Alignment problems

Post by Micr0 » 05 Aug 2017, 16:53

There is a problem in you calibration. From your description it could be caused by a number of things. Post some pictures of you equipment/setup with a brief description and I'll see can help.
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3dxcan
Posts: 74
Joined: 02 Jun 2017, 17:21

Re: Alignment problems

Post by 3dxcan » 06 Aug 2017, 18:03

Thanks Mircr0,
I believe my problem was that the projector was too bright and i had to close the lens Aperture too much, i had to set at about 8 to 16, now when i set the aperture to about 4 to 6, i get much better results and scans can be aligned automatically, however there's slight problem with alignment at larger lengths (1m), please refer to the pictures bellow:
Image
Image
Image

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Micr0
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Re: Alignment problems

Post by Micr0 » 07 Aug 2017, 14:33

Your images are broken. Too bright and you get noise in the scan. I haven't really seen this as distortion but if you scans are aligning better, That could a problem. Also make sure that all the projector settings for Image are set to zero. Settings like Keystoning, corner compensation, barrel and pin cushioning if you have them.
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3dxcan
Posts: 74
Joined: 02 Jun 2017, 17:21

Re: Alignment problems

Post by 3dxcan » 07 Aug 2017, 17:02

Micr0 wrote:
07 Aug 2017, 14:33
Your images are broken. Too bright and you get noise in the scan. I haven't really seen this as distortion but if you scans are aligning better, That could a problem. Also make sure that all the projector settings for Image are set to zero. Settings like Keystoning, corner compensation, barrel and pin cushioning if you have them.
Thanks for your reply, I'm using LG PF1500W projector, coupled with IS UX236, when i scan with aperture set at 4 to 6 i get better alignment. I used to close the aperture to 16, and i got bad alignment and a lot of noise. What Aperture value do you use?
Because the aperture is open, I dim down the projector brightness to nearly 0 in the settings (Contrast at 100) I've set the keystone and corner keystone values to zero, but barrel and pin cushioning, I haven't seen them in the settings. Could you please let me know where those settings are?

Image
Image
Image
Last edited by 3dxcan on 07 Aug 2017, 17:11, edited 1 time in total.

3dxcan
Posts: 74
Joined: 02 Jun 2017, 17:21

Re: Alignment problems

Post by 3dxcan » 07 Aug 2017, 17:08

Here are the pictures from the scans:
Attachments
Doc1_Page_3.jpg
Doc1_Page_2.jpg
Doc1_Page_1.jpg

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Micr0
Posts: 281
Joined: 15 Nov 2016, 15:20

Re: Alignment problems

Post by Micr0 » 08 Aug 2017, 01:40

3dxcan wrote:
07 Aug 2017, 17:08
Here are the pictures from the scans:
Without seeing your set up, I'd say that mismatch is from that part of the object being outside the optimal scan envelope (too far from the center of focus). Try moving your camera projector set up back further (you will have to re calibrate) and see if that helps.
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3dxcan
Posts: 74
Joined: 02 Jun 2017, 17:21

Re: Alignment problems

Post by 3dxcan » 08 Aug 2017, 18:06

Micr0 wrote:
08 Aug 2017, 01:40
3dxcan wrote:
07 Aug 2017, 17:08
Here are the pictures from the scans:
Without seeing your set up, I'd say that mismatch is from that part of the object being outside the optimal scan envelope (too far from the center of focus). Try moving your camera projector set up back further (you will have to re calibrate) and see if that helps.
Its a rather large object, almost 1m, so I have to pan and scan, then align the shots. do you mean to go further back to capture the entire object in 1 shot? or do you mean to crop the outer portion which isn't accurate and then align?
the setup is a single camera, IS UX236, 2.3MP, coupled with LG PF1500, using an inside calibration corner.

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Micr0
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Re: Alignment problems

Post by Micr0 » 10 Aug 2017, 11:29

3dxcan wrote:
08 Aug 2017, 18:06
Micr0 wrote:
08 Aug 2017, 01:40
3dxcan wrote:
07 Aug 2017, 17:08
Here are the pictures from the scans:
Without seeing your set up, I'd say that mismatch is from that part of the object being outside the optimal scan envelope (too far from the center of focus). Try moving your camera projector set up back further (you will have to re calibrate) and see if that helps.
Its a rather large object, almost 1m, so I have to pan and scan, then align the shots. do you mean to go further back to capture the entire object in 1 shot? or do you mean to crop the outer portion which isn't accurate and then align?
the setup is a single camera, IS UX236, 2.3MP, coupled with LG PF1500, using an inside calibration corner.
You can do it either way. Especially with long thng subjects it is easy to have part of it that is out of the optimized scan volume. I have found that when parts of my scans are not aligning or are distorted those parts are usually out at the periphery and I need to be more aware of where the part is in regards to the scan envelope.
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