nspots:number of picked spots
spots:geometric coordinates of the picked spots in the image
picked:actually picked colour values (rec2020)
ref:reference values (rec2020)
show:0 - picked, 1 - ref, 2 - diff
grab:indicates whether the results will be grabbed all the time (not only during regular pipeline reruns)
de76:a dummy parameter that gets filled with the CIE DE76 error metric between :picked:and :ref:
freeze:create a const module to replace this colour picker by frozen values. useful if you want to create a copy/pastable history
