Alignment problems

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3dxcan
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Joined: 02 Jun 2017, 17:21

Re: Alignment problems

Post by 3dxcan »

another example, when you scan the same object from different angles, the scans start to diverge at extemeties, here's another example,only 2 scans. I'm starting to think David is a waste of time and money.
Do you get the same effect or my equipment and settings maybe not optimized?
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Micr0
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Re: Alignment problems

Post by Micr0 »

1) What version of David are you using?

2) Did you turn off the OptomizeMultiCamera setting in the advanced settings?
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3dxcan
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Joined: 02 Jun 2017, 17:21

Re: Alignment problems

Post by 3dxcan »

Micr0 wrote: 10 Aug 2017, 16:05 1) What version of David are you using?

2) Did you turn off the OptomizeMultiCamera setting in the advanced settings?
Yes, i turned off OptimizeMultiCamera the moment i installed david. Its David 5.0.2 i think. I tried with the latest version too. Also tried version 4. I see no difference in my alignment problem.
I have disabled all keystone and corner keystone options in LG projector options too.
3dxcan
Posts: 74
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Re: Alignment problems

Post by 3dxcan »

Micr0 wrote: 10 Aug 2017, 16:05 1) What version of David are you using?

2) Did you turn off the OptomizeMultiCamera setting in the advanced settings?
Is there an option to automatically crop certain distance around the edges of the scans?
erapip
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Joined: 16 Dec 2016, 07:16

Re: Alignment problems

Post by erapip »

Carefully when you say " I'm starting to think David is a waste of time and money". A loot of people are making amazing things with DAVID for professional work as well (seescanprint3d of facebook).
Can you show the setup you are using and what hardware?
To show what DAVID do I'm attaching some pic.
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3dxcan
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Re: Alignment problems

Post by 3dxcan »

erapip wrote: 11 Aug 2017, 07:55 Carefully when you say " I'm starting to think David is a waste of time and money". A loot of people are making amazing things with DAVID for professional work as well (seescanprint3d of facebook).
Can you show the setup you are using and what hardware?
To show what DAVID do I'm attaching some pic.
your scans arent aligning and merging fine either, see this picture, your casting part is too rough to show were the each shot is merging to the other, but still you can see them not merging accurately here:
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Micr0
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Re: Alignment problems

Post by Micr0 »

3dxcan wrote: 11 Aug 2017, 14:40
erapip wrote: 11 Aug 2017, 07:55 Carefully when you say " I'm starting to think David is a waste of time and money". A loot of people are making amazing things with DAVID for professional work as well (seescanprint3d of facebook).
Can you show the setup you are using and what hardware?
To show what DAVID do I'm attaching some pic.
your scans arent aligning and merging fine either, see this picture, your casting part is too rough to show were the each shot is merging to the other, but still you can see them not merging accurately here:
Don't forget "Good, Fast, Cheap. Pick two." David is good and Cheap. It would be faster if you spent more $ and bought a preconfigured system. Even still there is a learning curve that you wouldn't have if you spent $30k of an Artc or Creaform. Part of the learning curve is getting it to do what you want to do with the support of a company you just gave a small boat load of $ assigning an engineer to help you configure/train.

Not that david isn't worth it, but (and I've said this before) getting what I call engineering level results out of hobby priced set up takes a lot of work on your part. I can personally attest that is possible. For me it took literally years of experimenting (I've been using David for nearly 5 years now, it still takes time each time I use it to carefully set up. Even then it sometimes gives me problems I have to solve. the difference is that the more I use and refine my process the faster I get. I also have a fairly good feeling of what Davids limitations are. I've looked at and used a number of scanners and understand that the major difference is the amount of engineering and refinement each system has. understand that that also clearly reflected in the price of the system.

3dxan: You need to spend some time experimenting if this is something you want to get good at. knowing the theory helps and I'll try to answer any questions I can. Also know that part of the years of experimentation I did was also research in the equipment and all the variables there. I spent literally months just learning about lenses and getting demo lenses from manufacturers. I even went so far to have a phone conversation with an engineer at Richo (in South korea) about the MTF profiles of various classes of their lenses. I mention this because all of these variables can play a pert in what you are doing. My instinct however is telling me that the miss alignment is coming from data that is captured outside of the optimal scan envelope. david's error rejection, correction and smoothing isn't the most sophisticated. I am also assuming that your calibration and calibration equipment is spot on. If not, there could be another source of your problem.
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Micr0
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Re: Alignment problems

Post by Micr0 »

P.S. This is possible:
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3dxcan
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Re: Alignment problems

Post by 3dxcan »

Micr0 wrote: 12 Aug 2017, 17:41 P.S. This is possible:
Dear Micr0,
You're always helpful and i can't appteciate it more. I didn't mean to rant against david or anyone's likings. I've been experimenting with david and my new system for a couple weeks and still learning, so please bear with me.
Anyways, I tried it with a 5 megapixel camera and lens, same results, so o decided to tone down the megapixel value of the camera to 2 in david settings, and now i have cropped image view but much more accurate alignments. I didnt find a way to crop the scans automatically other than that. Anyways, my guess is that either the lens isnt accurate enough to give worthy results for the whole field of view of the camera (only around the center of the image is accurate) or its the LG projector which is not capable of producing sharp image on the whole calibration panel and the part other the center of the projection.
Micr0, you also have the LG projector, so you know best what i mean. Please let me know what you think.
The new lens is TCL 1216 5MP from IS and the new camera is DMK 23UX178.
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Micr0
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Re: Alignment problems

Post by Micr0 »

3dxcan wrote: 12 Aug 2017, 19:10
Micr0 wrote: 12 Aug 2017, 17:41 P.S. This is possible:
Dear Micr0,
You're always helpful and i can't appteciate it more. I didn't mean to rant against david or anyone's likings. I've been experimenting with david and my new system for a couple weeks and still learning, so please bear with me.
Anyways, I tried it with a 5 megapixel camera and lens, same results, so o decided to tone down the megapixel value of the camera to 2 in david settings, and now i have cropped image view but much more accurate alignments. I didnt find a way to crop the scans automatically other than that. Anyways, my guess is that either the lens isnt accurate enough to give worthy results for the whole field of view of the camera (only around the center of the image is accurate) or its the LG projector which is not capable of producing sharp image on the whole calibration panel and the part other the center of the projection.
Micr0, you also have the LG projector, so you know best what i mean. Please let me know what you think.
The new lens is TCL 1216 5MP from IS and the new camera is DMK 23UX178.
Projectors are part of the problem when you get to near and far extremes of the scan envelope. They (their lenses) are designed to project onto a single flat plane. However David doesn't need perfectly focused images to work well and the calibration process is supposed to map some of that. Though there is a limit. I did want to experiment with the new Laser projectors that are now becoming cheaper. These have virtually no focal plane. I did get to try a cheap small Pico class projector. The surface quality of the resultant scans was horrible. I suspect that the extreme cohesiveness of the light and the scanning nature of the beam caused the poor surface finish of the scan. I was hoping to try a more expensive DLP laser projector and see if that was better. The other thing to note is that camera lenses are nonlinear as you move away from the center of the image. look at the MTF and OTF graphs. The more expensive the lense usually the better. Don't go by the megapixel rating. Again David supposedly compensates for this in calibration but I always think it is better not to have to calibrate around errors or shortcomings.
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