1. A method, comprising: receiving signals, from a rectangular array of sensor elements arranged in rows and columns, corresponding to an image captured by the array; analyzing the signals along a row or a column to identify one or more local turning points within the row or the column; processing the signals at the identified local turning points to determine whether the signals at the local turning point meet a given condition; calculating corrected values of the signals corresponding to the image captured by the array of sensor elements at the identified local turning points, by adding to the identified turning points meeting the given condition, a predetermined value which reduces the amplitude if the turning point is a maximum and which increases the amplitude if the turning point is a minimum, so as to reduce the fixed pattern noise in the image; and displaying the captured image with the calculated corrected values.