Page 1 of 1

Projector error and solution

Posted: 17 Jul 2017, 12:28
by Stive_Rad0
Hi.
After several test and getting mesh distortion, I think the problem is the projector. because when I use dual cam setup, distortion is reduced (dual setup can eliminate or reduce a portion of errors caused by projector).
can any one confirm some type of projector or projector lenses can make distortion? my projector is a old high end projector (Sharp XR-10X-L), but I think it is not good for this purpose. I noticed my projector creates a deviation about 3mm on 1m image for projecting a straight line (the lines are curved on top of image about 3mm, but on bottom of the image they have very smaller curvature. about 0.5mm).
dose any one have any solution?
I get very good details for single scans, but the problem is the alignment process.

Re: Projector error and solution

Posted: 17 Jul 2017, 17:45
by Micr0
Is you projector one of the older halogen lamp types? Or 3 beam designs?

Re: Projector error and solution

Posted: 17 Jul 2017, 18:10
by Stive_Rad0
thanks for your reply.
it is DLP Technology and with halogen lamp. I don't know 3beam design. what do you mean 3 beam design?
mine is: halogen lamp ==> light tunnel ==> color wheel ==> mirror ==> plastic lens ==> DMD ==> Projection lens
also I've removed color wheel.

Re: Projector error and solution

Posted: 17 Jul 2017, 18:51
by Micr0
1st thing is to make sure the projector is fully warmed up. Halogen projector will change in a number of ways as they warm that will throw a calibration off if it's done when the projector is cold. From there part of the calibration routine is David calibration the projector and compensating for minor distortions in the lense etc. That said, it is better not to have to calibrate around errors anywhere. have you made sure the keystoning and corner compensation are completely off?

Re: Projector error and solution

Posted: 17 Jul 2017, 19:12
by Stive_Rad0
even with warmed projector, I have distorted scans. I'm sure keystone in set to 0, and my projector do not have corner compensation.
as a test, I changed the projector mode to "border mode" and resize the image size. in this mode I can change the image position and it is possible to me to use different portion of lens to project patterns. and for different portion/section of lens, the distortion is changed.
sometimes I can get very very good calibration, but mostly it is not good.
Capture.JPG