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Author Topic: Basic Issue  (Read 2622 times)

ignarec

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Basic Issue
« on: October 14, 2017, 12:37:54 AM »
Hi, I've been getting this issue with my last 4 imports (see pictures attached).

So I've been trying to make a 3D model of a cranium.

Attached you'll find two screen captures of the outcome. One in which the results were successful and the other in which theres an issue with Agisoft detecting the object.

In the picture with the correct processing of the images, you can see that the photos where taken centripetal to the object at various angles. The same method was applied to all of the other models though the results were quite different.

Any clues?

SAV

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Re: Basic Issue
« Reply #1 on: October 14, 2017, 07:36:50 AM »
Hi ignarec,

Have you used masks both times? Have you also collected a similar amount of images (same image overlap)?

Regards,
SAV

ignarec

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Re: Basic Issue
« Reply #2 on: October 14, 2017, 02:45:51 PM »
Thank you SAV for your reply.

I cropped the images and got good results but the software cannot seem to be able to merge both sides (see new images attached to this reply).

The fist step I took was to create two chunks: "inferior" (with 49 photos) and "superior" (with 105 photos).

The photos of both chunks were properly aligned individually.

As I proceeded to align the photos of both of the groups I first merged both chunks.

Within the merged and aligned chunk you can see in one of the screenshots that it says "NA" corresponding to the inferior side of the object.

The bottom line is that I cannot align both sides of the object.
« Last Edit: October 14, 2017, 02:47:45 PM by ignarec »

someDude

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Re: Basic Issue
« Reply #3 on: October 14, 2017, 03:20:28 PM »
probably the surface of the scull isn't distinct enough. make it wet, and throw some coffe-powder on there. if the results get better, then you have a clue.
or your lighting isn't good enough or varies.

ignarec

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Re: Basic Issue
« Reply #4 on: October 14, 2017, 04:00:48 PM »
I've noticed that the lighting might be the issue.


In order to take pictures of the underside ("Inferior" side of the object) I made sure to cover the same ground from the "superior" side of the object. Though I flipped the skull over and the lighting changes to the opposite side.

When I compared the pictures that covered the same area (though one side was flipped and the other side was not) I noticed that the lighting clearly makes it seem like its another object.

ignarec

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Re: Basic Issue
« Reply #5 on: October 14, 2017, 04:03:17 PM »
probably the surface of the scull isn't distinct enough. make it wet, and throw some coffe-powder on there. if the results get better, then you have a clue.
or your lighting isn't good enough or varies.

So what are the best options when photographing the underside of an object? Are the lighting and the camera supposed to be aligned in the same axis?

Alexey Pasumansky

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Re: Basic Issue
« Reply #6 on: October 14, 2017, 04:14:05 PM »
Hello ignarec,

How you were performing the chunk alignment?

In case you have used point based alignment option - then you should have applied masks to all the images from both sub-sets covering the static background.
However, if you do so, then it may be reasonable to align all the images in the same chunk (using Constrain Features by Mask option) to avoid the possible issues related to the inaccurate chunk alignment.
Best regards,
Alexey Pasumansky,
Agisoft LLC

ignarec

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Re: Basic Issue
« Reply #7 on: October 14, 2017, 08:11:09 PM »
Hello ignarec,

How you were performing the chunk alignment?

In case you have used point based alignment option - then you should have applied masks to all the images from both sub-sets covering the static background.
However, if you do so, then it may be reasonable to align all the images in the same chunk (using Constrain Features by Mask option) to avoid the possible issues related to the inaccurate chunk alignment.

Thank you for your reply. I cannot seem to be able to align both chunks applying the masks (see screen capture and notice that the option is greyed out).