  In this paper, we provide a new insight to the two-phase signal segmentation
problem. We propose an augmented Lagrangian variational model based on
Chan-Vese's original one. By using both energy methods and PDE methods, we
show, in the one dimensional case, that the set of minimizers to the proposed
functional contains only binary functions and it coincides with the set of
minimizers to Chan-Vese's one. This fact allows us to obtain two important
features of the minimizers as a byproduct of our analysis. First of all, for a
piecewise constant initial signal, the jump set of any minimizer is a subset of
the jump set of the given signal. Secondly, all of the jump points of the
minimizer belong to the same level set of the signal, in a multivalued sense.
This last property permits to design a trivial algorithm for computing the
minimizers.
