Abstract: An audio system comprises a headset comprising a pair of earpieces positionable with respect to the user's ears so that, in use, the user is inhibited from hearing sounds from the user's environment, at least one of the earpieces having a transducer for reproducing sounds from an input audio signal; a microphone for generating a captured audio signal representing captured sounds from the user's environment; a detector for detecting the presence of any of a set of one or more characteristic sounds in the captured audio signal; and a controller operable to transmit sounds from the user's environment to the user in response to a detection that one or more of the set of characteristic sounds is present in the captured audio signal.

Abstract: A head-mountable display system comprises a head mountable display 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 for viewing by the observer. The frame comprises one or more shutters for obscuring the observer's view of the surrounding real environment and a display element mounted with respect to each of the eye display positions. The display element provides a virtual image of a video display of a video signal from a video signal source to the observer. An object detector detects the presence of an object within a detection range of the observer's head. And a controller controls operation of the head mountable display so as to allow the observer to view at least a portion of the surrounding real environment in response to detection of the presence of an object within the detection range.

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.