MirrorDome

The MirrorDome design was pioneered by visualisation researchers at Swinburne University who were looking for a more cost-effective way to achieve full dome or near full dome digital projection. Astronomers and telescope manufacturers have known for decades that using mirrors is much more cost effective than lenses. The same is true with the MirrorDome.

Features

MirrorDome uses a high quality spherical mirror to reflect the image from a DLP projector on to the dome. If a normal fisheye image were projected onto the mirror, severe distortions would be the result. Mirrordome developes the correct optical distortions or 'warping' to the original fisheye images, so that when the image hits the dome surface, the result is a perfect fisheye projection.

  • Cost
    Without the need for an expensive fisheye lens, this approach is far more cost effective than fisheye and truncated fisheye systems. The complete projection systems including all required hardware and software is under $US 14,000.

  • Flexibility
    The MirrorDome can use a much wider range of projectors than fisheye systems. This allows a choice of projector based on the luminosity, contrast ratio and brightness required.

  • More space
    Since the MirrorDome is positioned on the dome's perimeter, the best seat in the house is now available - the centre of your dome! This also maximizes capacity which is particularly relevant for smaller and portable domes.

  • Pixel Efficiency
    MirrorDome is able to project more of your projectors pixels on your dome than a comparable fisheye projection solution for 4:3 projectors.

  • Simple Setup
    Mirror dome simply uses a Macintosh 15" MacBookPro to drive the system. Combined with a single projector and lightweight mirror, the system can be setup in under 5 minutes in any dome. Ideal for portable domes, public outreach programs and full dome content preview.

  • Brightness Correction
    Our software uses an intensity mapping to correct for variable path lengths (and hence brightness) for different regions of the dome. The result is an even illumination across the entire dome.

  • Star Projectors
    Since the MirrorDome is positioned on the dome's perimeter, it is possible to keep your existing analog star projector.

  • Minor Drawbacks
    • Differing Pixel Sizes: Since the projector's square pixels are reflected at different angles off the spherical mirror surface, the shapes and sizes of pixels in different parts of the dome are marginally different.

    • Mirror Fragility: The spherical mirror used in the MirrorDome is a first surface mirror and hence it is more fragile than a conventional second surface mirror. Extra care needs to be taken when handling the mirror to avoid damaging the surface. In many ways it is similar to a projector lens, the only different being that the mirror is larger.

    • Full Dome Coverage: Whilst it's possible to achieve full dome coverage with the MirrorDome system, the optimal setup is to use a slightly truncated alignment where there are small regions of non projection in the rear of the dome. These regions are significantly smaller than a traditional truncated fisheye system, and if your audience is seated undirectionally, then these regions are not seen at all.