The Future is Now
3D Displays Aren’t Science Fiction Anymore
(This post originally appeared on Suture.online)
When I think of holograms, one of two things generally comes to my mind: either those 3D-image bookmarks that all the cool kids had in the 90’s or (nerd alert!) the Star Trek holodeck. Long an iconic staple of science fiction film and literature, holograms can seem more like figments of a far-off world than actual reality.
With that in mind, you can imagine my excitement when I stumbled across this video:
Pretty cool, right?
As soon as I watched it, I had to learn more. While I was unable to find the exact origin of this display, it looks quite a bit like the Hypervsn™ by Kino-Mo. It is, in essence, a souped-up version of the clocks that rapidly wave a lit rod back and forth, displaying the time in thin air.
Watching closely at the beginning of the video shows that the device is basically a fan with strips of LED lights. As it spins, the lights turn on and off and change color in a pre-programmed sequence. Kino-Mo claims that the process to use the Hypervsn is as easy as 1, 2, 3: set it up according to the manual, upload your 3D graphics to the program, and watch as customers are riveted to your awesome marketing display. With a design this simple, how does it manage to make it appear as though Pikachu were dancing right in front of you?
It may look like magic, but it’s actually science.
How it Works
Displays like this one are often referred to as “Persistence of Vision” (POV) displays. Persistence of vision refers to the optical illusion that occurs when multiple discrete images are interpreted by the brain as being one continuous moving image. It’s one of the theories behind why animation is able to trick our brain into interpreting it as real movement. In short, the theory states that when your eyes see an image, it’s retained by the brain for about 1/30th of a second (this varies slightly person to person and based on the brightness of the image). When the images move in fast enough succession, your brain retains enough of the information to form a comprehensive, moving picture of your surroundings. The faster the images appear, the more seamlessly they integrate together. An early example of this concept is the Phenakistoscope. This optical toy consisted of a spinning disc divided into sections, each containing part of an animated sequence. The image appeared to move when the observer spun the disc and stared at a fixed point on it.
The Hypervsn and similar devices are a type of POV display known as a swept volume display, referring to the fact that the moving projection surface (in this case, the fan blades)”sweeps” through a physical area of space (the volume). The projection surface emits lights in a pattern that corresponds to their location in space. If the volume is swept frequently enough, the brain will make use of POV and combine all of those tiny lights into one seamless image. This particular design makes use of a new type of LED light and incredibly high blade speeds that, in combination, create the 3-dimensional illusion shown in the video. The exact specs of this design understandably unavailable online, so these details are just what I could glean from the images on their website and info in other promotional articles.
The Hypervsn swept volume display is also unique in that it isn’t encased in a clear container, but open to its surroundings. This removes another visual barrier that might keep our brain from interpreting the displayed image as “real” and makes us more able to interpret it as 3D. The result is a marketing display that’s captivating because it tricks our brain just long enough for us to ask “…is that real?”
Relying on a spinning blade design does have some cons. Even though this device can create a 3D image, it’s only visible from the front. While not a problem for this device — it’s designed to be mounted on a wall for advertising purposes — it limits our sci-fi dreams of walking around and interacting with a holographic friend. The size of the display is also limited by the blades, meaning it would take quite a few of them lined up to project a life-sized human. The Hypervsn is pretty cool, but it isn’t going to let us project anything as complicated as a 3D, interactive, walk-through star map to Luke Skywalker.
I Want One!
You don’t need much technical knowledge to create your own simple swept volume light display. All you need is a bicycle, three AAA batteries, and an inexpensive programmable spoke light like this one. It’s a great exercise motivator: the faster your wheels spin, the more seamless the images will appear. In addition to making your bike more visible to cars at night, you’ll put on an awesome light show fueled by science!
When you get right down to it, the Hypervsn and other 3D POV displays are not actually holograms. A true 3D hologram a la science fiction wouldn’t require spinning blades or pre-programmed LED lights. It would require an advanced, real-time projection system (like BB8 or a holodeck) that produced a 3D image regardless of the viewer’s vantage point. We might not be quite there yet, but we’re getting closer. And I, for one, am pumped to see what other brilliant artistic engineers like Kino-Mo are going to bring us in the not-too-distant future.
*Disclaimer: This is not a paid post, and none of the links are affiliate; I just find the technology fascinating.