Abstract: A viewing device for viewing a video display on a display screen comprising the sequential display of right and left images of a video stereo pair, said viewing device including first and second spaced viewing structures positioned in front of the viewer's eyes, each structure alternating between viewing and masking conditions, and wherein reference images or markers are included in the video sequence which can be detected by an optical sensor for synchronisation of the conditions of the viewing structures with the images on the display screen.

Abstract: The invention relates to the provision of an optical device having first and second viewing passages which are selectively spaced apart to suit the interocular distance between a user's eyes. The device also included at least one image capturing device to allow a digital image to be captured. The invention provides a means whereby adjustment between the first and second viewing passages can be taken into account when capturing the image so as to reduce the problems caused by the angular adjustment.