[[File:Estimation of a mean height curve for boys from the Berkeley Growth Study with and without warping.gif|thumb|500pxupright=2|Estimation of a mean height curve (black) for boys from the Berkeley Growth Study with and without warping. The warping is based on latent variables that maps age to a synchronized biological age using a [[nonlinear mixed-effects model]].<ref name="Raket_et_al_2014">{{cite journal |vauthors=Raket LL, Sommer S, Markussen B |year=2014 |title=A nonlinear mixed-effects model for simultaneous smoothing and registration of functional data |journal=Pattern Recognition Letters |volume=38|pages=1-7 |doi=10.1016/j.patrec.2013.10.018}}</ref>]]
