  The new technique, multi-frequency imaging (MFI) is developed. In VLBI,
Multi-Frequency Imaging (MFI) consists of multi-frequency synthesis (MFS) and
multi-frequency analysis (MFA) of the VLBI data obtained from observations on
various frequencies. A set of linear deconvolution MFI algorithms is described.
The algorithms make it possible to obtain high quality images interpolated on
any given frequency inside any given bandwidth, and to derive reliable
estimates of spectral indexes for radio sources with continuum spectrum. Thus
MFI approach makes it is possible not only to improve the quality and fidelity
of the images and also essentially to derive the morphology of the observed
radio sources.
