  The IBIS telescope onboard INTEGRAL, the ESA gamma-ray space mission to be
launched in 2002, is a soft gamma-ray (20 keV - 10 MeV) device based on a coded
aperture imaging system. We describe here basic concepts of coded masks, the
imaging system of the IBIS telescope, and the standard data analysis procedures
to reconstruct sky images. This analysis includes, for both the low-energy
detector layer (ISGRI) and the high energy layer (PICSIT), iterative procedures
which decode recorded shadowgrams, search for and locate sources, clean for
secondary lobes, and then rotate and compose sky images. These procedures will
be implemented in the Quick Look and Standard Analysis of the INTEGRAL Science
Data Center (ISDC) as IBIS Instrument Specific Software.
