An infrared sensor assembly for sensing infrared radiation comprises infrared sensing elements and the infrared sensing compensation elements that are different so that, for a same flux on the infrared sensing elements and the infrared sensing compensation elements, the radiation responsive element of the infrared sensing elements absorbs more radiation than the radiation responsive element of the infrared sensing compensation elements, as to receive substantially more radiation than the radiation responsive element of the infrared sensing compensation elements. An output of the sensor array is a subtractive function of a sum of the signals of the plurality of infrared sensing elements and a sum of the signals of the plurality of the infrared sensing compensation elements such that at least linear and/or non-linear parasitic thermal fluxes are at least partly compensated for.