Forum

Author Topic: Problem Scanning Small Objects  (Read 5615 times)

RemnantDirector

  • Newbie
  • *
  • Posts: 2
    • View Profile
Problem Scanning Small Objects
« on: October 08, 2014, 12:36:36 AM »
I have been incredibly unsuccessful at trying to PhotoScan this small object.

https://drive.google.com/a/remnantstudios.com/folderview?id=0B69v2vH4LcSUV3l1OXBUS0N4cVk&usp=drive_web

I know it is a small object and could easily be modeled by hand but this is also to prove the workflow to my employer.  And this darn little ducky has stumped me.  Why can't I get my photos to align?  And even when I do get them to align they don't produce useful data along the centerline of the object?  Any thoughts?  Please let me know.

I've photographed this subject five different times.  I've used a circular polarizer at times.  I even drew unique designs all over the subject with a sharpie and still don't get useful data (although that helped the camera alignment).

Please let me know if you have any idea.  If you can stitch it all together and get a clean model I will buy you coffee (well at least I'll send you $10 via Paypal).  If you can do that and explain to me what I'm doing wrong I'll buy us both coffee (okay, that's not very incentivised).

Please share any insight you might be able to.

David Cockey

  • Full Member
  • ***
  • Posts: 207
    • View Profile
Re: Problem Scanning Small Objects
« Reply #1 on: October 08, 2014, 05:32:23 PM »
Based on my experience a random texture pattern is needed which has a scale of several pixels in the photographs. The pattern drawn on your object is much too large.

meshmixup

  • Jr. Member
  • **
  • Posts: 78
    • View Profile
Re: Problem Scanning Small Objects
« Reply #2 on: October 08, 2014, 07:47:19 PM »
Hi, the duck in the photo has only small focus area, due to small DoF. So each photo has only small amount of details available. You can try using smaller aperture for larger DoF in order to get clear pic of the whole object in each picture.

I just scanned a baby tricycle with shinny surface. My approach is to avoid sharp lighting, close up each portion and take as  many photo as possible (>100 photo in my case). Use clean background and no masking is required. Hope it helps :)
« Last Edit: October 08, 2014, 07:54:33 PM by meshmixup »

RemnantDirector

  • Newbie
  • *
  • Posts: 2
    • View Profile
Re: Problem Scanning Small Objects
« Reply #3 on: October 08, 2014, 08:15:22 PM »
Okay, so what about this set of photos?

https://drive.google.com/a/remnantstudios.com/folderview?id=0B69v2vH4LcSUNFF1VHMwaWF6ZTQ&usp=drive_web

The funny thing is that it successfully aligns and images the surface of the table, but I can not get a decent dense cloud of points from it.

hengefjes

  • Newbie
  • *
  • Posts: 49
    • View Profile
Re: Problem Scanning Small Objects
« Reply #4 on: October 08, 2014, 10:18:55 PM »
I guess your object doesn't have enough texture for the software to hang on to. You could try to mix chalk in water - spray it on and let it dry - (or anything else you can think of to give it some texture - play with it with greasy fingers ;-) then take the shots. It won't look as good, but at least the software will have more to work on and you get the 3d-shape. Try another sort object, like for instance a log of firewood.

dariusp

  • Newbie
  • *
  • Posts: 3
    • View Profile
Re: Problem Scanning Small Objects
« Reply #5 on: October 10, 2014, 01:33:31 AM »
Hi. You could try projecting a high-contrast noise pattern onto the duck, giving it a more complex pattern to align from. You photographs with noise and without. Align noisy images to create a model and then replace the noisy JPGs with the non-projected images to create textures. I'm just experimenting with this method and is showing great results on plastic objects with little texture on them.

You could setup two projectors with two unique noise patterns to cover all of the object or use one projector but capture in 2 chunks i.e. photograph 180 degrees of object then rotate object, repeat with different noise projection. These chunks will need aligning later in Photoscan and so a few small stickers for  markers will help.

Hope that makes sense? I've just got myself a cheap Pico projector for £40 and going to try that too, so can be done on the cheap. Currently doing a big R&D project and hopefully can share my findings in a few months.

good luck,

D