Passive Stereo

Click here to view our guides index

Currently, the only way to produce high quality stereo on a large screen is to use a projection system. Passive systems (e.g. our Duality range) consist of a pair of projectors, aligned using a custom rig. Each projector is fitted with a polarising filter, one at 90 degrees to the other. The viewer wears a pair of lightweight plastic or card polarising glasses which filter the light so that each of their eyes sees the image from one of the projectors.

The screen surface used in a passive system must be capable of maintaining the polarisation of the light. There are a range of special materials (both rigid and flexible) that will do this for both front and rear projection. Front projection material for passive projection is far less expensive than that for rear projection.

Starlight Express road show featuring digital 3D-projection by Inition

Active versus Passive Stereo

Active systems using shutter glasses have been around for a long time and were once the only option for digital stereoscopic projection. They require either CRT or DLP projectors because of the high refresh rate required (~120Hz) to switch quickly between both eyes without noticable flicker. Passive systems are usually based on a pair of LCD projectors.

	Passive Projection System				Active Projection System
	Relatively inexpensive				Relatively expensive
	Large choice of projectors and lenses				Limited choice
	Card or plastic 3d glasses are lightweight and inexpensive and can be branded				Glasses are bulky, fragile and expensive
	Alignment required during installation/setup				No alignment required as only single projector
	Head must remain fairly level for 3D filters to work*				Can be viewed with head tilted to one side
	Must use a special non-depolarising screen				Can use standard screen materials

* This can be worked around by using circular polarising filters, instead of linear.

If you have any questions about stereoscopic displays then please call +44 (0)20 7613 5004 or email inition@inition.co.uk. We have a wide range of 3d screens available to view in our central London demo suite. Please contact us to arrange an appointment.

top