Half of the object's point cloud does not match

[EliasAviles]

I took photos all around the object from many angles and different proximity.
In some cases I have close ups of different parts of the object.

The problem is when zephyr creates the point cloud, the object seems to be separated when it reaches the half part and it offsets it, this has been happening not only with this object but with every other I made a turntable.

I hope the pic can clarify my problem.

Is there a setting i'm missing for this process or the specific way of feeding the program the photos?

Thanks in advance

[SarahC]

I found this happens when the background has repeating elements, and the image matching finds enough overlap to "dis-guard" the orientation of the model.
It also happened when I selected a detailed sparse point cloud for a set of mounted insect images. It spotted a part of a repeating pattern on a wing or something, and rotated the entire point cloud for a set of images to match up with that repeat!

Are you masking the image in Zephyr?
Knocking out the background might reduce angle calculation accuracy a tiny bit in the structure from motion step (Forum Mods, is that the case? I imagine using the distant background is a great way to accurately find the angle of a photo.), but it will prevent false photo pair matches if your background consists of repeating patterns like wallpaper, or wooden boards.

If that doesn't work - stick your model on a detailed flat surface, and chop that off the created model / detailed point cloud inside Zephyr. You'll be providing a lot more points to match up, than those of the model itself, which should prevent a false match.

[Andrea Alessi]

Hi Elias,

this most likely happened because of the background. If you're moving the the subject, you'll have background and the subject in an incoherent reference system. In some cases you might be lucky and zephyr might actually orient the subject, but in most cases it'll orient the background rather than the subject.

If you're moving the subject you'll have to mask them https://www.youtube.com/watch?v=dGRw8LbXknU

[EliasAviles]

Thanks for your responses and tips,
The issue here is that my photos have a full black background (meaning no background elements), so there is no information to be matching on the background, another thing i might havd pointed before, is that i am feeding zephyr a set of photos, this meaning that a have a turntable of the upper part of the character, a turntable of the motorcyvle part, another turntable for the face and another turntable for de details of the wheels.
With this new info, do i have to consider something new?
Thanks again!

[Andrea Alessi]

You may not see anything, but Zephyr will find features in the cloth or background. You can check with the match viewer to see if this is the case, but since you have a uniform background it should take just a few minutes in masquerade to mask everything. If you want to share the dataset i can have a look at it so i can give more specific advice