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Author Topic: Way to follow with a white model?  (Read 10995 times)

zzgus

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Way to follow with a white model?
« on: March 25, 2011, 12:22:48 PM »
I have a little white model (about 20cm) I want to try with Photoscan.

I have read that will not work with unpainted models.
Can I simply paint it randomly with some spray colors?
Will it be enough?
What's the better process to follow with this model?

Thankyou
Gus

zzgus

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Re: Way to follow with a white model?
« Reply #1 on: March 26, 2011, 02:37:31 AM »
C'mon Dmitry put some light !!!

Gus

Dmitry Semyonov

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Re: Way to follow with a white model?
« Reply #2 on: March 27, 2011, 05:55:33 PM »
Hello Gus,

You are right, painting the uniform object with a random pattern should be enough to obtain a good model.

Just try to keep the size of the pattern details small compared to the size of the object. You may try several patterns to find the optimal one.

If for some reason you'll find the results unsatisfactory, please let me know. Probably I could give some advices about improving a pattern used.

With best regards,
Dmitry Semyonov
AgiSoft LLC
With best regards,
Dmitry Semyonov
Agisoft

FoodMan

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Re: Re: Way to follow with a white model?
« Reply #3 on: March 28, 2011, 10:05:07 AM »
maybe spray with a color paint from far to get micro drops on your model..

0.2 cents
H/

zzgus

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Re: Re: Way to follow with a white model?
« Reply #4 on: March 28, 2011, 11:47:12 AM »
Referent to:
If for some reason you'll find the results unsatisfactory, please let me know. Probably I could give some advices about improving a pattern used.

Yes please, tell me the way to proceed or what will be the best pattern. I think it will be interesting for a lot of people.

I was thinking with a simple little "Fisherman's network" like the one's used in the windows to prevent mosquitos.

Thankyou
Gus

Dmitry Semyonov

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Re: Way to follow with a white model?
« Reply #5 on: March 28, 2011, 06:16:27 PM »
Hello Gus,

I would recommend using irregular pattern if possible. A regular grid may produce unstable results as the grid corners will be matched unreliably across the photos.

So the idea with spraying the model with a color paint seems to be a better approach. Alternatively you can paint some irregular pattern, like graffiti for example.

With best regards,
Dmitry Semyonov
AgiSoft LLC
With best regards,
Dmitry Semyonov
Agisoft

IanJohnson

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Re: Way to follow with a white model?
« Reply #6 on: May 05, 2011, 03:00:03 AM »

I know this is an old topic, but the information might be helpful.  If you are trying to scan an object that is allowed to be painted, look for a spray paint that is meant to create a fake stone texture.  These paints have a clear base with bits of sand or something in it.  If there are very fine details that you want to capture, spray a very light coat to avoid filling them in.

I recently scanned a small chocolate so that I could scale it up, print it, and make a mold for chocolate shaped soaps.  I used Photosynth Toolkit (before I learned of PhotoScan), and you can see it here-

http://photosynth.net/view.aspx?cid=2cda0ef4-6efa-4726-acdd-2702785dfaa7

The painted on texture worked very well, though sadly I couldn't eat the chocolate when I was done.

JMR

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Re: Way to follow with a white model?
« Reply #7 on: May 05, 2011, 04:16:26 PM »
Hello:
White objects are allways challenging but also those with flat colours or poor texture.
I've had some success (but with different programs) by projecting a rich texture onto white object by means of one or two lcd projectors during shots. A dense text is a good texture to try with.
Take two shots from each camera pose, so you can have the same picture with and without artificial texture (make sure you don't move the projectors during photograps) .
I dont think Photoscan keeps needing texture once you have oriented photos and created model, so it should work if you simply rename untextured photos to the same names as textured ones and apply clean photos to your model. Share your results if worked.
Regards

FoodMan

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Re: Way to follow with a white model?
« Reply #8 on: May 08, 2011, 02:06:00 PM »
hey this is a nice idea...

Jan Wesbuer

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Re: Way to follow with a white model?
« Reply #9 on: May 08, 2011, 03:58:25 PM »
Hi,

if someone needs a random noise pattern in highres as an image for projecting ... i could render that out and share it.

Regards
Jan
i use PS Pro, C4D and ZBrush on OS X

John Root

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Re: Way to follow with a white model?
« Reply #10 on: May 09, 2011, 05:38:56 PM »
In our tests we've found that crisp focus and a deep depth of field is critical to a good reconstruction. To obtain this, one needs a lot of light. We never tried projecting a noise pattern as it was theorized that when the flashes  triggered, it would simply blow out the projection. Instead we opted to paint the object with a high contrast matte noise. We've been getting really good reconstructions this way. Of course we are sacrificing the albedo for mesh quality.

How have you dealt with the projection getting drown by the flash?
How have you dealt with the projection stretching when collinear to a surface?
How have you dealt with the projection having limited resolution and diffusion?

Jan Wesbuer

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Re: Way to follow with a white model?
« Reply #11 on: May 09, 2011, 06:52:40 PM »
Hi JROOt,

i agree with you on your arguments on getting drown of the projection by flash.

I personally use lamps and i have often aperture times of 0,5-2 sec (in caves) whats not limiting the image quality too much (with tripod and remote triggering) as my objects normally do not move.
But i guess for surfaces with very uniform colorization there are only two possibilities:
-projection of a pattern (or more to avoid stretching) or
-painting it with a noisepattern.

Reflecting surfaces are bad for many cases and should be avoided.
And i guess a dia projector would be best because of the imageresolution limitation.
(Making a dia with sharp highres image)

I have not used noise projection until now, but i know that this was used for other programs with success.

Best regards
Jan
i use PS Pro, C4D and ZBrush on OS X

andy_s

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Re: Way to follow with a white model?
« Reply #12 on: February 19, 2013, 04:01:04 PM »
Hi,

if someone needs a random noise pattern in highres as an image for projecting ... i could render that out and share it.

Regards
Jan

Hi Jan, doing a little forum "back to front" at the moment - apologies if there was an update on a more recent post. I'd appreciate that noise pattern - if the offer is still there.