Extraction of ridges.
[POINTST,POINTSF]=ridges(TFR,HAT) [POINTST,POINTSF]=ridges(TFR,HAT,T) [POINTST,POINTSF]=ridges(TFR,HAT,T,METHOD) [POINTST,POINTSF]=ridges(TFR,HAT,T,METHOD,TRACE) [POINTST,POINTSF]=ridges(...,'plot')
time-frequency representation
complex matrix of the reassignment vectors.
the time instant(s).
the chosen representation (default: 'tfrrsp').
A boolean (or a real scalar) if true (or nonzero),the progression of the algorithm is shown (default : %f).
when called with the additional string 'plot', the output values will be plotted
a real vector: the time coordinates of the stationary points of the reassignment.
a real vector: the frequency coordinates of the stationary points of the reassignment. Therefore, plot(POINTST,POINTSF,'.') shows the squeleton of the representation.
ridges extracts the ridges of a time-frequency distribution. These ridges are some particular sets of curves deduced from the stationary points of their reassignment operators.
sig=fmlin(128,0.1,0.4); g=window("kr",21,3*%pi)'; h=window("kr",47,3*%pi)'; t=1:2:127; [tfr,rtfr,hat]=tfrrspwv(sig,t,128,g,h); [pt,pf]=ridges(tfr,hat,t,'tfrrspwv'); clf; Sgrayplot(t,linspace(0,0.5,128),tfr') plot(pt,pf,".k") | ![]() | ![]() |