Pointing system and method

A method of locating a point in a projected image, comprising:

• displaying an image onto a display surface in response to a stream of image data received from an image data source;
• frames of the image being displayed as composites of image data fields sequentially displayed during a frame imaging time;
• displaying control information onto the display surface together with the image data from the image stream using a flat field encoding scheme, whereby control data is imaged differently at different locations in the sequentially displayed fields and the different imaging at the different locations sums to image a uniform intensity and color in the composite frame image;
• pointing a detector at a selected location in the displayed image and detecting a succession of intensities of the control data displayed at the selected location for the respective sequentially displayed fields, the different imaging of the control data displayed in later displayed ones of the sequentially displayed fields being determined by the intensities of the control data detected in earlier ones of the sequentially displayed fields;
• and
• determining the selected location from the detected succession of intensities.