A method of measuring temperature based upon a system of equations applying Stefan-Boltzmann's law and using a measurement value for an object to be measured and an ambient temperature value (Ta) comprises: pre-calculating (200, 202) a first vector (LUT1) and a second vector (LUT2). The first vector (LUT1) is a series of values proportional to received power based upon respective temperature values and in respect of a predetermined generic range of temperatures. The second vector (LUT2) is a series of sensitivity characteristic factor values based upon expected measured temperature values and in respect of a predetermined range of expected object measured temperatures. The first vector (LUT1) and the second vector (LUT2) are used (206) to generate a temporary vector (LUTT) of a series of values limited to the ambient temperature value to solve the system of equations in respect of the measurement value for the object, thereby determining (208) a temperature (To) for the object from the measurement value.