RIDGEINTERP Interpolate quantity values onto ridge locations. RIDGEINTERP is a low-level function called by RIDGEWALK. XI=RIDGEINTERP(FS,RQ,IR,JR,X) where RQ is a "ridge quantity" at *radian* frequencies FS, and IR and JR are time and scale indices of ridges, interpolates quantity X along the ridge locations to give XI. IR and JR give indices into the first two dimensions of X. The output XI has the the same number of rows and columns as IR and JR, that is, SIZE(XI,1)=SIZE(IR,1) and SIZE(XI,2)=SIZE(IR,2). The locations of NANs in IR and JR are duplicated in XI. X may have more than one 'page' along its third dimension, in which case each page is interpolated separately, and SIZE(XI,3)=SIZE(X,3). RQ is output by ISRIDGEPOINT based on a wavelet transform output by WAVETRANS, and IR and JR are output by RIDGEWALK. RIDGEINTERP interpolates transform values between discrete frequency levels to find a more precise value of the transform along the ridges than simply looking up the values of X at rows IR and columns JR. XI=RIDGEINTERP(FS,RQ,IR,JR,MU,X) interprets the ridges as belonging to the MU-th derivative of the signal to which the quantity X belongs and applies an appropriate correction factor. [XI1,XI2,...,XIN]=RIDGEINTERP(FS,RQ,IR,JR,X1,X2,...,XN) also interpolates the quantities X1,X2,...,XN, all having the same number of rows and columns as IR and JR. RIDGEINTERP uses fast quadratic interpolation via QUADINTERP. In rare cases, quadratic interpolation fails for an individual point and therefore linear interpolation is used instead. __________________________________________________________________ RIDGEINTERP is a low-level function called by RIDGEWALK. See also RIDGEWALK, ISRIDGEPOINT, QUADINTERP. Usage: xi=ridgeinterp(rq,ir,jr,x); [xi1,xi2,xi3]=ridgeinterp(rq,ir,jr,x1,x2,x3); __________________________________________________________________ This is part of JLAB --- type 'help jlab' for more information (C) 2005--2019 J.M. Lilly --- type 'help jlab_license' for details