Abstract: A communication system comprises means defining a communication region, such as a touch-pad (151), having associated therewith a plurality of symbols (155) or the like and being responsive to a user-controlled pointing device whereby a desired symbol or the like can be selected by movement of the pointing device in a predetermined direction within the region (151).

Abstract: A method of selecting a cell (1) from an array (3) comprising the steps of: providing a first array (3) of sixteen cells (1) and selecting a second array (5) of four cells from the first array of sixteen cells; and selecting a single cell (1) from the second array of four cells.

Abstract: A method is provided for inputting characters to an electronic device having a virtual keyboard displayed on a screen. The method includes the step of displaying a plurality of character entry regions (1). Each region is adapted to display either, at a first level, a plurality of character options, or, at a second level, a single character option from the plurality of character options from a previously selected region. The number of regions and the number of characters is such that a desired character option can always be selected with no more than two keystrokes.

Abstract: A method of employing a gaze direction tracking system for control of a computer comprises the steps of: providing a computer display incorporating a screen and at least one off-screen control target (1, 2, 3, 4); and eye-pointing by a user at the control target. The eye-pointing is detected by the gaze control tracking system so as to effect a predetermined control action in the computer.

Abstract: A target (3, 207) is monitored using an image sensor (5, 201) for producing a signal indicative of an image received by the sensor, and processing the image signal. The image signal is processed using a comparator (105) for determining the amplitude of the image signal and for identifying any part or parts of the signal having an amplitude greater than a predetermined threshold (VTR). Location coordinates of the part or parts of the signal having an amplitude greater than the predetermined threshold are then determined.

Abstract: Apparatus for the position sensing of a remote target. A preferred embodiment is used to control the position of a graphical pointer on a computer screen. A light emitting diode illuminates the head of the computer operator and an array of detectors detect radiation returned by a retroreflector attached to the head of the operator. Signal processing means is included to derive information about the position of the operator's head from the detector outputs and convert it to a form suitable for input to computer.