Abstract: The invention provides a method of compensating for crosstalk between electromagnetic sensors in an array, each sensor having a flux transformer with a current therein which does not vary smoothly with an applied magnetic field, each sensor configured to produce an output signal comprising a stepwise varying component and a finely varying component. The method comprises, for each sensor to be compensated, applying a crosstalk compensation function to the output signal of the sensor to be compensated, the crosstalk compensation function based at least in part on at least one of the stepwise and the finely varying components of at least one other of the sensors in the array.