Agisoft Metashape

Agisoft Metashape => General => Topic started by: xiu2014 on May 14, 2014, 06:17:32 AM

Title: Aligning photos
Post by: xiu2014 on May 14, 2014, 06:17:32 AM
My English is poor. Do not know what reason, camera shooting pictures around after the. Alignment is not very good.
Title: Re: Aligning photos
Post by: Alexey Pasumansky on May 14, 2014, 07:21:37 AM
Hello xiu2014,

I can recommend to use more shots around the object, since eight photos for the full circle around the object seems to be insufficient. 15-20 images will provide better overlap and, therefore, more stable alignment.

Also I think that the reflection of the object in the liquid should be masked prior to processing.
Title: Re: Aligning photos
Post by: xiu2014 on May 14, 2014, 07:32:49 AM
thank you
Title: Re: Aligning photos
Post by: xiu2014 on May 14, 2014, 07:36:20 AM
Hello xiu2014,

I can recommend to use more shots around the object, since eight photos for the full circle around the object seems to be insufficient. 15-20 images will provide better overlap and, therefore, more stable alignment.

Also I think that the reflection of the object in the liquid should be masked prior to processing.
I tried to shoot more photos, but the photo alignment is always wrong. I try to surround the 36 shots, but the photo alignment only 180 ° or less, and the position of the camera. I'll go crazy.
Title: Re: Aligning photos
Post by: Alexey Pasumansky on May 14, 2014, 07:44:42 AM
Hello xiu2014,

Could you please provide the full image set?
Title: Re: Aligning photos
Post by: xiu2014 on May 14, 2014, 08:41:27 AM
https://drive.google.com/file/d/0B78YNevp7k89TWFSRnBKX1h0MmM/edit?usp=sharing
Title: Re: Aligning photos
Post by: xiu2014 on May 14, 2014, 11:57:42 AM
https://drive.google.com/file/d/0B78YNevp7k89WnNpUmpjeEFxWDA/edit?usp=sharing
Title: Re: Aligning photos
Post by: Andrew on May 14, 2014, 12:47:53 PM
xiu2014, did you take a look at your photos in full resolution? Most of them have incredibly shallow depth of field, only a tiny portion of photographed object is sharp, the rest is blurry. No wonder Photoscan can't match these photos well. Also, top ring of photos is shot from too radically different perspective in relation to bottom rings. Photos within any given ring of photos align well to one another because each next photo is shot from only slightly different perspective (low angle between camera positions). But difference in perspective between any photo from top ring and any photo from other rings is just too significant.

Cheers,
Andrew
Title: Re: Aligning photos
Post by: xiu2014 on May 14, 2014, 02:41:56 PM
Andrew
thank you.
How do I improve to ensure alignment? I use 2 zoom camera now and a fixed focus. Using of manual zoom, I try to make the shot object is clear enough.
Title: Re: Aligning photos
Post by: Andrew on May 14, 2014, 04:56:48 PM
Master your photography skills :) Use Aperture Priority on your camera with f8-f13 setting. Depending on amount of available light you might be forced to increase ISO. Remember to have enough overlap between photos that are supposed to align with one another (in case of project you uploaded - top ring of cameras were too high up compared to the other to rings of photos. Your top ring also looked almost straight down at center of scanned object so all these photos captured almost the same amount of information).

-Andrew
Title: Re: Aligning photos
Post by: xiu2014 on May 15, 2014, 07:52:44 AM
I tried to adjust, occasionally still has this problem, all the photos are almost in line.
Title: Re: Aligning photos
Post by: meshmixup on May 15, 2014, 08:33:10 AM
my 2 percent input: increase the DoF as others mentioned, avoid smooth surface (e.g. your table) and put other objects near by to help camera position alignment.

This is how I started my experiment before. :)
Title: Re: Aligning photos
Post by: xiu2014 on May 19, 2014, 03:39:39 AM
meshmixup
Thank you