A breakthrough. An augmented reality does something that appears to be simple but in fact is really tricky and lets you hide a virtual object behind a real one. I'm Jonathan Strickland, and this is tech stuff. Daily. Augmented reality involves using some form of display or output device to overlay digital information on top of the real data we
encounter out in the physical world. The typical representation of this is some form of goggles or handheld display that overlays computer generated imagery on top of a view of our physical surroundings. This is just one type of augmented reality, but it's a common one. There are numerous smartphone apps that will let you look at the world through your smartphone screen. You're looking at a live video feed captured
by the smartphones camera. The app will overlay some sort of digital information on top of your live video view of the world. It might be directions, such as an arrow pointing to the indicating you need to make a left turn to get to your pizza parlor. Or it might be a virtual character in a game, perhaps a big boss you have to battle before you can cross the threshold of your local pizza parlor to get a pepperoni slice. It's lunchtime. But one challenge a our developers
have faced is called occlusion. Occlusion in this sense is all about an object blocking another object in the real world. If one opaque object passes behind another, of course we lose sight of it for a moment. For example, if we play hide and seek and you go stand behind a tree. When I look around, I'm not going to see you, assuming of course you're using the tree to block my view of you. And if you walk in front of the tree, I'll see you, but I won't be able to see the parts of the tree you're
covering up. This is obvious. We experience this every day, so I know I'm not sharing anything new with you. But now let's imagine we're using an augmented reality application and hardware. We have to teach this system to recognize the border of real world objects within view. It also must recognize the relative distance of those objects from the camera, as well as the virtual distance between the display and
the virtual object. Only then can such a system allow for a virtual object to pass behind or in front of a real one and have it reflected in the display so it looks like it's really happening in front of your eyes. This is a non trivial problem. A research team at the University of Arizona's College of Optical Sciences have a prototype display that tackles this issue. Their display allows for a virtual object to be blocked by a real world object. It also allows the virtual object
to block other objects that are behind it. That behind was in air quotes, because obviously the virtual object isn't really in the physical space at all. According to Professor Hong Hua, the display takes the view of the real world and with lenses, images it upon a spatial light modulator. These are devices that can alter or modulate polarization, amplitude, and phase of light beams. They often will modify the intensity of a lightbeam, though more advanced ones can do
all sorts of funky things with light. The team used a spatial light modulator to create a mask that blocks out the bit of the real world that the virtual object will inhabit. This modulated image is what then reaches the display that you can see. One thing that's necessary to make all this work is a depth sensor. Without a depth sensor, the system cannot know which objects are
closer to the lens and which are further away. There needs to be a way to measure that distance and then calculate where a virtual object should fall based upon that objects virtual distance from the viewer. This is a big jump from just overlaying a digital image on top of a video view of the world. This is incorporating computer generated imagery into a real environment as if it too were just as real. Law says that it will likely be sometime before we see this capability built into
consumer headsets. She says her team's solution wasn't exactly sleek and sexy. They were just trying to get a system that worked. Refining that system into something more consumer friendly will take some time to get it down to a format that might fit in, say a pair of special glasses will take even more time, but the foundation is there. To learn more about augmented reality, mixed reality, and all sorts of other types of reality. Subscribe to the Tech
Stuff podcast every Wednesday and Friday. I look at big topics and tech and really explore how they work and why they're important. I'll see you again soon.