Derivation of a Generalized Asymmetry Helicity Parameter for Multi-look PolSAR Data

The helicity asymmetry parameter
$\tau$
in the Cameron decomposition indicates the degree to which a scatterer deviates from being an ideal symmetric scatterer. However, the solving procedure of
$\tau$
can only be expressed in terms of single-look Sinclair scattering matrix. In this paper, we extend the helicity
$\tau$
to a generalized helicity parameter
$\tau_{g}$
, which is appropriate for both the single-look and multi-look PolSAR data. For single-look data, the generalized helicity
$\tau_{g}$
is equivalent to the previous helicity
$\tau$
.