Slough, Berkshire-based Ambitron Ltd showed for the first time in the UK the low cost desktop virtual reality system CrystalEyes VR – and three-dimensional video system from Stereographics Corp of San Rafael, at the Virtual Reality ’93 Conference in London earlier this month. The UKP6,000 desktop system is suitable for any stereo-ready workstation, Apple Computer Inc Macintosh, personal computer or monitor. It includes an ultra-sonic head tracking device that sits on top of the monitor and lightweight three-dimensional goggles. The head-tracking device enables users to move images simply by moving their heads – the images change perspective in line with any changes in location. The goggles work by having their liquid crystal diode lenses synchronised to the refresh rate of the monitor. Under the control of an infra-red emitter, each lens alternately opens and closes, to present images to the eye. The system is said to be particularly useful for industrial and scientific applications like molecular modelling, computer animation, robotics control. The video system comprises a view-record controller, playback controller and cameras. The view-record controller converts standard video signals, generated by two standard video cameras, into a single signal for sequential video display. The cameras can be mounted on a stereo base or can be part of stereo instruments such as microscopes or laproscropes. The camera signals are stored in separate buffers and the controller reads them at twice the rate at which they were written. The playback controller converts the multiplexed signal into a 100-fields-per-second stereoscopic signal. Signals are passed from the recorder to the playback controller and then to a stereo ready monitor. The resulting images can be viewed in three dimensions using the CrystalEyes goggles. The system is not cheap – the record controller and two cameras cost UKP25,000, the playback controller is UKP5,000. But it has apparently proven useful for microscopic surgery – and has also been used by US cult band the Grateful Dead, who recorded their recent revival concert in three dimensions.
