This paper covers a fundamental problem of local phase
based signal processing: the isotropic generalization of the
classical 1D analytic signal to two dimensions. The well
known analytic signal enables the analysis of local phase
and amplitude information of 1D signals. Local phase, amplitude
and additional orientation information can be extracted
by the 2D monogenic signal with the restriction to
the subclass of intrinsically one dimensional signals. In
case of 2D image signals the monogenic signal enables the
rotationally invariant analysis of lines and edges. In this
work we present the 2D analytic signal as a novel generalization
of both the analytic signal and the 2D monogenic
signal. In case of 2D image signals the 2D analytic signal
enables the isotropic analysis of lines, edges, corners
and junctions in one unified framework. Furthermore, we
show that 2D signals exist per se in a 3D projective subspace
of the homogeneous conformal space which delivers
a descri...