Applicability of inverse heat flux evaluation to thermographic measurements in SPIDER

As the front observation is not convenient, it is necessary to solve an inverse non-linear problem to determine the energy flux profile impinging on the calorimeter, starting from the 2D temperature pattern measured on the rear side of the tiles. The aim of the paper is to give an overview about the transfer function technique which may be used to retrieve the flux profile, dealing with non-linearity and non-stationariness.