1 : A data processing method for processing hyperspectral image data of a scene, the method comprising: a) sequentially receiving portions of the data at a data buffer to form a data set comprising a predefined number of data portions; b) calculating a set of global statistical parameters and data correction factors using the data forming the data set; c) receiving a further data portion at the data buffer and simultaneously removing the earliest received data portion at the data buffer, from the data set, d) calculating a set of local statistical parameters using the data of the further data portion; e) updating the set of global statistical parameters using the set of local statistical parameters; f) correcting the data of the data portion removed from the data set using the correction factors; and g) outputting the corrected data portion and set of global statistical parameters calculated using the data set comprising the removed data portion, to a processor.