Head-mountable display system

A method of operation of a head-mountable display system having a frame to be mounted onto an observer's head, the frame defining one or two eye display positions which, in use, are positioned in front of a respective eye of the observer;

• and a display element mounted with respect to each of the eye display positions, the display element providing a virtual image of a video display of a video signal from a video signal source to that eye of the observer;
• the method comprising:
• detecting motion of the observer's head;
• generating a higher frequency component and a lower frequency component of the detected motion, according to a threshold frequency;
• and
• controlling the display of the video signal in dependence upon the detected head motion, the controller acting to compensate for the lower frequency component of motion of the observer's head by moving the displayed image in the opposite direction to that of the detected motion so as to change the apparent viewpoint of the observer in the direction of the detected motion, and to compensate for the higher frequency component of motion of the observer's head by moving the displayed image in the same direction as that of the detected motion.