Mid-point construction used in the interference diagram
[TI,FI] = midpoint(T1, F1, T2, F2, K)
a real vector of size N: the time-coordinate(s) of the first point(s)
a real vector of size N with positive elements: the frequency-coordinate(s) of the first point(s)
a real vector of size N: the time-coordinate(s) of the second point(s)
a real vector of size N with positive elements: the frequency-coordinate(s) of the second point(s)
a real scalar: the power of the group-delay law
K = 2 :Wigner-Ville
K = 1/2 :D-Flandrin
K = 0:Bertrand (unitary)
K = -1 :Unterberger (active)
K = %inf :Margenau-Hill-Rihaczek
a real row vector of size N: the time-coordinate(s) of the interference term(s)
a real row vector of size N: frequency-coordinate(s) of the interference term(s)
midpoint gives the coordinates in the time-frequency plane of the interference-term corresponding to the points (T1,F1) and (T2,F2), for a distribution in the affine class perfectly localized on power-law group-delays of the form : tx(nu)=t0+c nu^(K-1).