  A framework for parameterization of the light response functions (LRFs) in a
scintillation camera is presented. It is based on approximation of the measured
or simulated photosensor response with weighted sums of uniform cubic B-splines
or their tensor products. The LRFs represented in this way are smooth,
computationally inexpensive to evaluate and require much less computer memory
than non-parametric alternatives. The parameters are found in a straightforward
way by the linear least squares method. Several techniques that allow to reduce
the storage and processing power requirements were developed. A software
library for fitting simulated and measured light response with spline functions
was developed and integrated into an open source software package ANTS2
designed for simulation and data processing for Anger camera type detectors.
