Being interested in the way to figure out the centroid!

[YushengEdward]

Hi,
Thanks you very much for your help in the past, again!
When i use sextrctor to figure out the centroid of extracted source, it seems to use both semi-major axis、semi-minor axis and background flux.
I want to know if i remove the background flux, will there be any problem? Or how does the backgroud flux matter in the process?
Edward

[Eririf]

background subtraction is opened by default
turn off in configuration file and try it