The present invention relates to a controller comprising: at least two input terminals, each of which is configured to receive one of at least two input signals comprising information on a positioning of a scanner relative to a reference medium, and an output terminal, which is connectable to the scanner and configured to transmit an output signal, which is used for controlling the positioning of the scanner, wherein the controller further comprises: a processing unit being operable to designate a corresponding weighting function to each of the at least two input signals, a magnitude of the corresponding weighting function being selected to be in accordance with a noise profile of the input signal to which it has been designated; the processing unit further being operable to simultaneously use the at least two input signals, each with the corresponding weighting function designated thereto, to design a transfer function of the controller for use in the production of the output signal.