#the docstrings for the method calculate from pyslid
def calculate( conn, iid, scale=1, set="slf33", field=True, rid=None, pixels=0, channels=, zslice=0, timepoint=0, threshold=None, debug=False ):
Calculates and returns a feature ids vector, a feature vector and the output scale given a valid
image identification (iid). It currently can calculate SLF33, SLF34, SLF35 and SLF36.
This method will try to retrieve the resolution of the image from the annotations.
If the method is unable to connect to the OMERO.server, then the method will return None.