Usage of -filter-quality

Hi,
I have modified the script OSC_Preprocessing_withbackgroundextraction.ssf
to use -filter-quality in the script to remove lower quality images:

stack r_bkg_pp_light rej 3 3 -norm=addscale -output_norm -filter-quality=80% -out=…/result

but it seems that there is no information needed to evaluate single frames, so no stack is made.

Warning: some images don’t have information available for best images selection, using only available data (0 images on 30).

Is there something missing in the script?

Thanks

Quality is only computer with planetary algorithms.
Here you will need fwhm, wfwhm or roundness.

thank you very much