Light field displays are gradually changing how we see the world around us. Or rather, how we see the world that isn’t around us. From classic photography to advanced education and diagnostics to remote presence and entertainment, this article will look at what a light field display is, how different display types work, and how they’re used.
A Quick Walk Through Light Fields and Light Field Photography
Just like any other display, the content viewed on a light field display must be either captured from the real world or created by an artist.
Content captured from the real world to be viewed on a light field display is traditionally captured with a light field camera. Light field cameras work more or less like regular cameras, but they record the intensity and direction of light allowing the focus to be adjusted later on. Photographers have been using this technique for over a hundred years, but more modern applications put these interactions into the hands of end-users.
Content created for viewing on a light field display is usually made using software that “stitches” 2D images together to create a 3D model. If you’ve ever seen something being 3D-printed, the process is similar, but, instead of using layers of a physical substance like plastic, the “layers” are graphics like photographs or computer-generated images.
Some emerging technologies are combining conventional light field cameras with volumetric capture. Volumetric capture is more complicated and expensive than light field photography, but it’s better at generating 3D models of moving people and objects in real-time.
How Do Light Field Displays Work?
There are also two main ways of creating light field displays. Some light field displays are head-worn devices, similar to what you might think of when you imagine virtual reality headsets.
Some light field displays are made up of a 2D screen and optional accessory pieces to create something that looks like a cross between a tablet and an old television. As we’ll see, both of these options have their own affordances and limitations.
How Tabletop Light Field Displays Work
Tabletop light field displays work on a 2D screen. Through a process called “quilting,” different parts of the display show slightly different angles of the same image or video. When users look at the display from different angles, it creates the illusion of looking at the displayed person, object, or model from different angles. The flagship of this kind of technology is the Looking Glass.
The principal upshot of tabletop displays is that multiple people can view a single image displayed on a single device at the same time. The biggest downside to this kind of display is that the display itself remains stationary.
How Head-Mounted Light Field Displays Work
Head-mounted light field displays typically use some kind of waveguide technology. Different manufacturers have different approaches to this, but the general takeaway in all cases is that the display guides light from an onboard projector through the lens to the eye. This replicates the way that the eye views physical objects, so good displays that are getting better all the time make for a convincing experience.
There isn’t one clear leader in this technology in the same way that there is a clear leader in tabletop displays. The most familiar examples are probably the Microsoft HoloLens 2 and the Magic Leap 1. However, a number of other contenders exist in the enterprise and military fields.
As you might have guessed, the pros and cons of head-mounted light field displays are exactly the opposites of those presented by tabletop light field displays. A single head-mounted light field display cannot be used by multiple users simultaneously, but the wearer of a head-mounted light field display can move around a model or the representations of other users as in remote presence use cases.
Use Cases for Different Light Field Displays
The principal use cases for light field displays are collaboration around a digital model and remote presence.
Microsoft’s recently announced Mesh platform might be the first and greatest use case for a remote presence light field application that would allow users on different sides of the world to meet in real-time with or without a shared virtual space. That is, the virtual representations of remote persons will appear to be present in the physical space of the user.
Meanwhile, Xenco Medical’s HoloMedX uses diagnostic imaging data to create a 3D model of an individual patient’s specific anatomy viewed by the patient with a medical expert on a Looking Glass display. Because the Looking Glass light field display doesn’t require a headset, the patient and the medical expert are able to share a face-to-face interaction that doesn’t require either of them to move around one another or around the model.
Have You Seen a Light Field Display?
Right now, light field displays are still expensive enough and light field content is niche enough that most uses are pretty specialized. However, these displays are becoming increasingly common and events like concerts are increasingly being broadcast to such devices. So, it might not be long before these devices and experiences become a typical part of our lives.