  Point-source contamination in high-precision Cosmic Microwave Background
(CMB) maps severely affects the precision of cosmological parameter estimates.
Among the methods that have been proposed for source detection, wavelet
techniques based on ``optimal'' filters have been proposed.In this paper we
show that these filters are in fact only restrictive cases of a more general
class of matched filters that optimize signal-to-noise ratio and that have, in
general, better source detection capabilities, especially for lower amplitude
sources. These conclusions are confirmed by some numerical experiments.
\keywords{Methods: data analysis -- Methods: statistical
