Update for FunctorFilter
Raffaele and Agnès told me to re-use the module you did to ease their use on Qgis. As I have a recent version of OTB UnaryFunctorImageFilter, BinaryFunctorImageFilter disappeared to the profit of the FunctorFilter.
I made the changes but as a guest in irstea gitlab I have no right to do a pull request on a repository without permission nor create a fork. So the files are here if you want it ;) https://framagit.org/SPeillet/NDVITimeSeries