Recording disparate left and right eye views on separate, synchronised tape recorders has obvious advantages, but the cost, unwieldy post-production, and storage requinments may exclude small scale and industrial users. There is a need for a simple system of recording 3D TV images on a single tape.It may be possible to accommodate stereo pictures in little more than the bandwidth of conventional video, for example by coding as left channel plus left.right difference signal. Simpler techniques involve discarding infonnation, but in practise this can be of little visible consequence.Two methods of combining left and right views into a video signal which can be recorded on any format video recorder are described. The first involves multiplexing fields from the left and right channels. On playback the fields are separated and each displayed twice to avoid ificker. Vertical resolution is reduced, but this is subjectively acceptable.With the second technique portions of the left and right views are combined in a side-by-side half frame fonnat. Horizontal, vertical and temporal resolution are unaffected, but picture size is reduced and aspect-ratio changed. This format is useful when recorded data is input to an image processing system.

Previously we have emphasised the need for accurate picture matching and the proper convergence of left and right channels of a stereoscopic camera to ensure that the image is comfortable to view and does not cause fatigue. This usually procludes the use of standard zoom lenses in high quality 3D television cameras as the optical alignment frequently changes with focal length and two such lenses, when motorised, would have to be controlled with great accuracy to avoid viewer discomfort. This paper describes the on-going development of a compact zoom lens specifically for stereoscopic television in nuclear environments. Custom designed optics in radiation tolerant glass provide a focal length of 12.5mm to 36mm with a package length of less than 1 10mm. A novel method of encoding the position of the lens elements allows for very compact motonsation and a precision mechanism designed to overcome backlash ensures the stability of picture matching.The position of the lens elements is controlled by a 16 bit microcontroller and the control strategy allows focus and convergence to be maintained to a high degree of accuracy during zooming.2

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Included in an EuropeanProject about stereoscopic Imaging, a 3D pick-up equipment will be developed. This equipment represents an advance tool inasmuch as the goal is to built an automatic and motorised camera. The motorisation ofthis equipment allows precise and remote controls. This is required to provide the large and symetric adjustments for optics and the system. This means we modify the values of the optical and mechanical parameters (focal length, interaxial, angle of convergence) to provide optimal stereo pictures. Two kinds offunctionning are planned. The first kind corresponds to preprogrammed values which regulate all parameters for an expected stereoscopic quality. The second kind allows the cameraman to be free in order to introduce special effects or test special condition to obtain psychophysical results. The image quality will correspond to the CCIR 601 standard for both channels.