When should I use the stacking parameter "-overlap_norm"?

Software Siril
1

I shoot alt/az and so I have field rotation.

So I use the -maximize feature to stack into a larger frame as well as the -feather option to feather the borders. These options work great.

However, I’m wondering about the option “-overlap_norm” and what value that may provide in my situation. The documentation says:

-overlap_norm , if passed, will compute normalization coeffcients on images overlaps instead of whole images (allowed only if -maximize is passed).

What can people tell me about what affect this option has and when it should be used? Would it be good for stacks from images that have offsets and rotations so they don’t fully overlap?

Thanks!

2

Hi Steven,

There are more details in the documentation about image stitching here:Stacking — Siril 1.4.0-beta1 documentation

In your case, i would recommend NOT to use it. While you have field rotation, your images are mostly overlapping. The option is intended for stitching mosaic tiles with little overlaps, where the statistics of each tile wrt its neighbours may be different because each tile captures a different part of the sky.

Cheers

Cecile