Abstract: A head-mountable display system comprises a frame to be mounted onto an observer's head. The frame defines one or two eye display positions for positioning in front of a respective eye of the observer. A display element is mounted with respect to each of the eye display positions, and provides a virtual image of a video display of a video signal from a video signal source to that eye of the observer. A motion detector detects motion of the observer's head. A high-pass filter is arranged to generate higher frequency and lower frequency components of the detected motion, according to a threshold frequency associated with the response of the high-pass filter. And a controller controls the display of the video signal based upon the detected motion, to compensate for the higher frequency component of motion by moving the displayed image in an opposite direction to that of the detected motion.