The Laboratory of Robotics Systems (LSRO) has recently developed a high precision robot with 6 degrees of freedom. This robot needs to be calibrated. To this end, a large amount of input-output pairs has been measured (input: position of the motors, output: position of the end-effector); the measurement points are distributed in a non-uniform fashion. At these "training points" the input-output relation is known exactly. At all other points the relation is found by interpolation (or, in the case of noisy measurements, by approximation). The goal of this project is to implement a fast algorithm that performs spline-based interpolation of 6D data with non-uniform measurements. This project is done in collaboration with the Laboratory of Robotics Systems.