Forum

Author Topic: Automatically remove shadows and dim areas from calculations ?  (Read 2049 times)

sonno

  • Newbie
  • *
  • Posts: 34
    • View Profile
Hi,

I would like to make a 3D model of an object that has a lot of shadows all around on its rough and rugged surface. The object was in motion with fixed lighting but there is a great variety of shadows.

I want to remove these shadows for the calculations. For this I use "magic wand" with a tolerance of 30% for example and I click in the shadow, right click "Add selection" to define an exclusion mask. But the manipulation is very long on the number of photos.

Do you know a trick to remove the shadow areas and therefore the dim areas on a photo, typically that all pixels < 50% max lum are not taken into account in the calculations ?

Do you know if we can use and control the magic wand in python ?

All the best,

Alexey Pasumansky

  • Agisoft Technical Support
  • Hero Member
  • *****
  • Posts: 15124
    • View Profile
Re: Automatically remove shadows and dim areas from calculations ?
« Reply #1 on: April 27, 2023, 07:24:52 PM »
Hello sonno,

Probably you need to create such masks in the external application that allows for more complex instruments, and then import the masks to Metashape.

But note, that the reconstructed surface would be less accurate if it appears only on a few images.
Best regards,
Alexey Pasumansky,
Agisoft LLC

sonno

  • Newbie
  • *
  • Posts: 34
    • View Profile
Re: Automatically remove shadows and dim areas from calculations ?
« Reply #2 on: April 29, 2023, 12:17:57 PM »
Alexey,

In fact I have many images but as there is only one incident light source, a part of the object shadows a second part. the calculation seems to be thwarted because of the shadows because on many images there is the information (illuminated part) and on many others the same part not illuminated.

With the magic wand, you just have to click on the 4 corners of the image to define an exclusion zone for the calculation from the outside of the object. The work task is very long and repetitive. So I used the WinParrot software to reproduce the task on all the images. https://www.winparrot.com/

The software is easy to use and programmable in a loop...

If one day you have the time to add options in Metashape to solve this problem of shadows, it would be perfect.