Yes, those are the correct default settings for
symmetric=True then the initial morphology is perfectly symmetric (so yes, sigma=1).
thresh sets a minimal gradient. By default
thresh=0, which means that the morphology can be flat. When
monotonicity=True, in an attempt to keep the initial footprint as small as possible
thresh=0.1, enforcing a slight gradient.
The default constraints for
constraints = (sc.SimpleConstraint() &
SimpleConstraint is slightly more restrictive than
MinimalConstraint, as it also uses
scarlet.operators.prox_center_on, which prevents a source from having zero flux in it’s central pixel (which can cause the location of a source to drift off to infinity).