How do I exclude black velvet background from image alignment?

[Ucodia]

Hi there,

I am shooting using a 360 turntable on a black velvet with a strong flash and cross polarization.
Though an issue I get is that it seems that Metashape is able to pickup dust particle and/or the surface of the black velvet and uses this to align pictures.
As a result, each series done after rotating the object on the turntable end up aligning on the same exact path, which is wrong.
I use darktable to process my images and apply white balance, color calibration (color checker) and exposure.

How do I exclude those particles during the alignment step so that each camera path is well recognized and avoid black artifacts in the model?

In the 4 pictures I attached:
1. Original picture
2. Picture with all depth map levels
3. View of the model and alignment
4. Settings used during alignment

[SimonBrown]

Masks are the answer. They can be created in Metashape or external applications such as Photoshop.

We have recently updated our Foundation Course to include working with these, and there is a great worked example that can be downloaded and worked through.

https://accupixel.co.uk/courses/metashape-foundation-course-for-forensics-surveying/

One tip: Get the subject to fill as much as the frame as possible. Working from distance and then masking will work, but you are losing detail that could have included the subject.

[Ucodia]

Masks are the answer. They can be created in Metashape or external applications such as Photoshop.

We have recently updated our Foundation Course to include working with these, and there is a great worked example that can be downloaded and worked through.

https://accupixel.co.uk/courses/metashape-foundation-course-for-forensics-surveying/

One tip: Get the subject to fill as much as the frame as possible. Working from distance and then masking will work, but you are losing detail that could have included the subject.

Thank you for your answer, I was not aware of the masking option, I used a black background for masking and it works fantastic, thank you!

Attached image for the fixed alignment.