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Mira – From <$20 Fishbowl To New Mario Kart Ride at Universal Japan (In About 4 years)
Introduction
Today want to congratulate Mira Reality, a little over 4-year-old startup. Mira has seen their AR headset designed into a major theme park attraction at Universal Studios Japan. The theme park opened Nintendo World on Feb 4th, 2021, with a Mario Kart dark ride that uses Mira’s AR Headset to mix virtual images with video screens and sets within the rest of the attraction. A ride-through video can be seen here. Below is a screen-shot from the video.
Figuring that a major theme park attraction takes many years to develop, Mira must have been only a year or two old when they got the design win.
Maybe Universal Took the Advice I Gave to Disney
I first wrote about Mira back in 2017 in the article Mira Prism and Dreamworld AR – (What Disney Should Have Done?). Disney had just released a Star Wars headset and lightsaber and I wrote that they should have gone with something simpler like Mira’s headset. I find it interesting that Universal, Disney’s arch-rival and which must have been in the design of Mario Karts at the time, decided to use Mira. I don’t know there is a connection, but the timing is about right.
Starting with a Cut-Up Fishbowl
Two months after writing the Mira/Disney article in 2017, I visited Mira’s headquarters in Los Angeles. They not only showed me their finished headset, but they also showed me how they built their first prototype.
Mira bought a wall hanging clear acrylic fishbowl for the prototype and cut it up to make the curved mirrors/combiners. They found a company to partially mirror coat the insides of the cut-up sections of the fishbowl and glued them together (see below)—a far cry from the 3+Billion dollars spent by Magic Leap.
Mira has entrepreneurs after my own heart. In 2013, I hacked together Navdy’s first prototype (and then much copied) aftermarket automotive hud in my garage (see the Appendix of this article on HUDs and photo on the right).
Think about it. Mira when from a cut-up fishbowl (less than $20 on Amazon) to a design win at a major theme park in less than 2 years. I often say that it is sad that today in AR that so much money is going to the hucksters like Magic Leap.
Mira’s Design Seems to be a Great Match for a Theme Park Attraction
My first thought was that Mira’s design is a great match for the Mario Kart ride. The Mario Kart ride headset has three main parts, 1) the headband with cap, 2) a cell-phone sized display with connection to the video, and 3) the curved combiner. The original Mira design had the combiner held in magnetically.
The design is simple and low cost to make while affording huge eye relief so that anyone with glasses can wear them (see right). The Mira design also has a huge eye box, so that alignment is not critical. The eye relief and eyebox are critical to having a practical design in an application where you are fitting thousands of people an hour.
The combiner is inexpensive, trival to replace, and made of plastic. Minor scratches are not going to significantly degrade the image quality. It is unlikely to brake and will not be a serious safety hazard if it does break.
While in line, the rider puts on the adjustable headband (only). Only as the rider gets to the vehicle is the display inserted into the headband followed by the clipping on the curved combiner. The way the whole thing can be broken down into pieces also means it should be easier to sanitize, even more important in this era. The headband and combiner can be swapped out and cleaned as is done with 3-D glasses.
As it is an off-axis curved combiner, the image will be distorted, but it is not going to matter much for this type of application, and they can pre-correct the image. Other than distortion, the image quality is going to be good. Being indoors, the display does not have to be very bright. And being that you are on a theme park ride, it does not have to look like ordinary glasses. In short, it leverages the strengths and is not hurt by the weakness of Mira’s AR display technology.
Should Be the Start of a New Trend
I see so many AR headsets used in applications that make me shake my head. It is so nice to see one where the fit between the requirement and technology are so well matched. I expect we will be seeing this approach copied not only in other Universal Nintendo Lands around the world but in other attractions.
Fans of this Blog
BTW, I was much honored by the folks at Mira with a “fan” picture they sent me back in 2018.
Closing – Lots to Write About
I have so much to write about that I hardly know where to start. Hopefully, the inspiration from Mira will be the start of a trend.
Hi Karl,
I agree, some small startups do more with much less. While cosmetically it might not look as marketable it seems more practical, cheap and with better imaging specs.
I love that Nintendo seems to be slowly getting over the VirtualBoy failure. They made an experimental Google Cardboard – like product for their Switch console not too long ago as well: https://youtu.be/z4jCbt4FM7Y .
The Mario Kart video AR game is also pretty fun: https://youtu.be/fan5FrujNPo
Another smaller startup I like is TiltFive/CastAR. Have you heard about them? I was doing a similar project with two pico projectors strapped to a worker’s helmet when I learned about them. I’m going to get my dev kit in a month or so. I have a pretty good understanding of that tech and we can do a teardown and some measurements.
Thanks,
I know about TiltFive (and CastAR). I think I understand how it works with retro-reflective screens and projectors. While I like Jeri Ellsworth’s tenacity and story (great interview on The AR Show https://www.thearshow.com/podcast/076a-jeri-ellsworth-part-1), I’m not convinced the approach is going to support a very large market.
You really have to see how much “gain” the retro reflective screens provide when the projection lens is so close to your eyes. Let’s just say the 7.0 gain of some commercial projection screens are nothing in comparison. This allows to reduce the aperture stop of the projection lens to have the image almost always in focus, with LED illumination. This also improves the image contrast ratio by quite a bit compared to F/2.5 since the liquid crystal polarization efficiency depends on the beam AOI.
For sure the use case is limited, but it may be interesting to check the image quality.
Hi Karl,
what do you think about the XR headset (HMD-VS1W) from JVC Kenwood? Based on the article it suggests selective direct view capability with a large FoV. Curious how they can make the optics reflect the projected images and blocking real-world light with this birdbath style setup.
https://www.roadtovr.com/jvc-enterprise-xr-120-fov-5k-resolution/
Thanks for the question.
It looks like it works similar to the ODG R9 or Nreal only on a larger scale. The R9 and Nreal both use an OLED Microdisplay whereas the JVC/Kenwood one likely uses a bright LCD (although it could be an OLED). Disney-Lenovo’s Star Wars headset did something similar (see:https://kguttag.com/2017/07/18/disney-lenovo-ar-headset-part-1/) only the JVC unit is using two displays that are higher resolution. Perhaps similar to Pixmax’s “5K” (2.5K wide per eye) only with a large birdbath. It would be like JVC combined the Disney Starwars headset with the Pixmax 5K.
In these type of birdbaths, the curve front mirror is a partial reflector and so is the beam splitter. Typically these types of birdbaths block about 70% or more of the real-world light or are similar to fairly dark sunglasses. They typically transmit less than 20% of the display’s light to the eye. But since the birdbath is also blocking the real world light it can be workable for indoor use.
Thanks Karl,
the article suggest that they can selectively block parts of the real-world view with a occlusion filter of some sort. With the non blocked view the user can perceive the real-world (the dashboard/steering wheel in the video). But with ~70% of the real-world light blocked it does not really need an occlusion filter or they selectively change the transparency of the beam splitter.
I think you may be reading in the article capability that is not there. The problem with doing occasion is that the real world is out of focus at the distance of the glasses. It is brought into focus by the eye’s cornea. So there is no practical way to selectively block (known as a hard-edge occasion) the real world.
[…] schnitt das Start-up aus einem Plastikfischglas, das weniger als 20 US-Dollar kostet, erinnert sich der Techblogger Karl Guttag, der den Prototyp 2017 zu Gesicht bekam und die Prism-Brille als ideale Lösung für die […]
[…] The ability to replace the waveguide can be extremely important for some applications, particularly those in rugged use where lenses can get scratched or broken. It could also lead to some unique applications such as what happened with Mira for their use in theme parks (see: Mira – From <$20 Fishbowl To New Mario Kart Ride at Universal Japan (In About 4 years). […]