  The manifestation of point sources in the upcoming PLANCK maps is a direct
reflection of the properties of the pixelized antenna beam shape for each
frequency, which is related to the scan strategy, pointing accuracy, noise
properties and map-making algorithm. In this paper we firstly compare
analytically two filters for the PLANCK point source extraction, namely, the
adaptive top-hat filter (ATHF), the theoretically-optimal filter (TOF). Our
analyses are based on the premise that the experiment parameters the TOF assume
and require are already known: the CMB and noise power spectrum and a circular
Gaussian beam shape and size, whereas the ATHF does not need any a priori
knowledge. The analyses show that the TOF is optimal in terms of the gain after
the parameter inputs. We simulate the PLANCK HFI 100 GHz channel with
elliptical beam in rotation to test the efficiency of the TOF and the ATHF. We
also apply the ATHF on the WMAP Q-band map and the derived map (the
foreground-cleaned map by Tegmark, de Oliveira Costa & Hamilton) from the WMAP
1-year data. The uncertainties on the angular power spectrum will hamper the
efficiency of the TOF. To tackle the real situations for the PLANCK point
source extraction, most importantly, the elliptical beam shape with slow
precession and change of the ellipticity ratio due to possible mirror
degradation effect, the ATHF is computationally efficient and well suited for
the construction of the PLANCK Early Release Compact Source Catalogue.
