  This paper introduces the use of pseudo-filters that optimize the
detection/extraction of sources on a background. We assume as a first approach
that such sources are described by a spherical (central) profile and that the
background is represented by a homogeneous and isotropic random field. We make
an n-dimensional treatment making emphasis in astrophysical applications for
spectra, images and volumes, for the cases of exponential and Gaussian source
profiles and scale-free power spectra to represent the background.
