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corner distortion

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corner distortion

Postby moog » Tue Aug 16, 2011 9:57 am

I've tried V3-09, and i find it much easier to get a good quality, less noisy, less stepped scan, than with 08.
I have however got some distortion, of the scanned corner ( reverse corner)
Can someone advise a possible cause ?
I think its either the focal length limitation of projector, or position of camera or something..
( the corner is perfectly flat)
Attachments
09-1.jpg
LC532-5-3-F(16x65), BenQ PB8220 DLP Projector, logitec quickcam PRO9001, Casio EX-FH20
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Re: corner distortion

Postby moog » Tue Aug 16, 2011 10:26 am

i just moved the camera and it came out straight , but the live view misses a triangle out at the top...
I'll keep trying....
Attachments
09-2.jpg
09-3.jpg
LC532-5-3-F(16x65), BenQ PB8220 DLP Projector, logitec quickcam PRO9001, Casio EX-FH20
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Re: corner distortion

Postby MagWeb » Tue Aug 16, 2011 10:44 pm

Hi,

maybe the background structure in its 3D simulation intersects the image plane? How does that look like from above?

Just a hint: You´ve set the focus of the projector right on the edge of the corner. I got better results setting it quite in the middle of the visible area of the planes (here: about there were the single ringmarker is) and leave the edge a bit unsharp....

Gunter
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Re: corner distortion

Postby moog » Wed Aug 17, 2011 8:50 am

Gunter, you're right about the background intersecting the image plane.
My next job is to modify my logitec 9000 into a logitec 9001, i guess this would avoid this happening ??
Attachments
09-4.jpg
LC532-5-3-F(16x65), BenQ PB8220 DLP Projector, logitec quickcam PRO9001, Casio EX-FH20
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Re: corner distortion

Postby moog » Wed Aug 17, 2011 9:23 am

i moved the camera down a bit, and it's not intersecting the plane now, but i seem to have a small distortion again
(intersection angle is 35 degrees)
what am i doing differently, i didn't notice this with V3-08 ?
Attachments
09-5.jpg
09-6.jpg
LC532-5-3-F(16x65), BenQ PB8220 DLP Projector, logitec quickcam PRO9001, Casio EX-FH20
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Re: corner distortion

Postby moog » Wed Aug 17, 2011 9:57 am

i've moved it down even further (to an intersection angle of 21 degrees)
now the distortion has gone the other way?
Attachments
09-7.jpg
09-8.jpg
LC532-5-3-F(16x65), BenQ PB8220 DLP Projector, logitec quickcam PRO9001, Casio EX-FH20
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Re: corner distortion

Postby moog » Thu Aug 18, 2011 10:04 am

Is there a setting for the screen aspect ratio ?
My screen appears to be squashed in the vertical direction, the pics show the same part rotated thru 90 degrees
Attachments
09-gen4.jpg
09-gen5.jpg
LC532-5-3-F(16x65), BenQ PB8220 DLP Projector, logitec quickcam PRO9001, Casio EX-FH20
moog
 
Posts: 235
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Re: corner distortion

Postby Mike_A » Sun Aug 21, 2011 3:24 am

Gday Moog,
I had a similar problem a while back, I still haven't managed to fix it.
viewtopic.php?f=16&t=3313#p18318
I'd be really interested to see if someone has a solution for this.
regards,
Mike.
532nm 5mw 3V Green line laser
Stepper-11YPG302S-LW4-R100 with 100:1 gear ratio Gearbox
Mono Camera - DMK31AU03. 1024 x 768 / 30fps
Arduino UNO/EasyDriver V4
Acer K11 Projector.
www.mikeannear.com
Perth, Western Australia.
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Re: corner distortion

Postby WalterMo » Sun Aug 21, 2011 7:09 pm

@Moog:

Please explain more in detail what you mean.
If I take a ruler and measure the total lenght of your scanned object I don't find a difference.
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Re: corner distortion

Postby moog » Mon Aug 22, 2011 12:11 am

i just did a similar measurement off these jpegs, and found no difference, but all i can say is, that, on the screen, in real time, there was some squashing of the view, i'll try to replicate it again.
To save those jpegs, i did a screen print, paste and crop in photoshop, i wonder if somehow the aspect ratio didn't save with the pics?
LC532-5-3-F(16x65), BenQ PB8220 DLP Projector, logitec quickcam PRO9001, Casio EX-FH20
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Re: corner distortion

Postby moog » Mon Aug 22, 2011 10:11 am

I've modified my pro9000 into a pro9001, and this is my first errorts.
with regards to the corner distortion, i did 2 scans the first had an intersection of 25 degrees, and had distortion.
Attachments
09001-1.jpg
09001-2.jpg
LC532-5-3-F(16x65), BenQ PB8220 DLP Projector, logitec quickcam PRO9001, Casio EX-FH20
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Re: corner distortion

Postby moog » Mon Aug 22, 2011 10:14 am

the second, i moved just the camera up, and got 31.5 degrees intersection, and there was no distortion........
I'm not making any conclusions yet...... but maybe camera position is more critical?
Attachments
09001-3.jpg
09001-4.jpg
LC532-5-3-F(16x65), BenQ PB8220 DLP Projector, logitec quickcam PRO9001, Casio EX-FH20
moog
 
Posts: 235
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Re: corner distortion

Postby moog » Mon Aug 22, 2011 11:23 am

with regards to the aspect ratio...
I've just saved this view of one side of the scanned plane.....
the distance over 5 markers in a horizontal direction is 152mm (on screen)
the distance over 5 markers in a vertical direction is 119mm (on screen)
then i rotated the scan and saved another jpeg.
The ratio also changes direction
Attachments
plane-1.jpg
plane-3.jpg
LC532-5-3-F(16x65), BenQ PB8220 DLP Projector, logitec quickcam PRO9001, Casio EX-FH20
moog
 
Posts: 235
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Re: corner distortion

Postby Mike_A » Sun Aug 28, 2011 10:49 am

Hi Moog,
I think Ive cracked it.
I turned the "Keystone" adjustment on my projector to "0",
It seems to fix the edge distortion of positive and negative corners.
Cheers,
Mike.
532nm 5mw 3V Green line laser
Stepper-11YPG302S-LW4-R100 with 100:1 gear ratio Gearbox
Mono Camera - DMK31AU03. 1024 x 768 / 30fps
Arduino UNO/EasyDriver V4
Acer K11 Projector.
www.mikeannear.com
Perth, Western Australia.
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Re: corner distortion

Postby lostandfound » Sat Sep 10, 2011 6:11 pm

Mike_A wrote:Hi Moog,
I think Ive cracked it.
I turned the "Keystone" adjustment on my projector to "0",
It seems to fix the edge distortion of positive and negative corners.
Cheers,
Mike.


That makes a lot of sense, as the keystone setting is pretty much default all parameters...
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