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Valve engineer explains how Lighthouse (positional tracking) works (Tested interview)

Krejlooc iirc didn't say if it will support the Vive. Currently it supports the Rift, but with Oculus deprecating DX9 support it won't work eventually (edit1: actually it doesn't anymore).

edit2:

Don't worry, hl2vr will live again once the vive launches.

ah
 
Valve engineer was at Maker Faire this weekend to talk about non-VR use for Lighthouse

and here's a blog post

This article is nice, and it provides some additional information on how multiple Lighthouses are differentiated (a subject that was discussed on the last page):
Like many IR systems, the LEDs and lasers are actually modulated (Alan said, "on the order of MHz"). This is useful for a few reasons: (1) to distinguish the desired light signals from other IR interferers such as the sun; and (2) to permit multiple transmitters with different modulation frequencies.
 

efyu_lemonardo

May I have a cookie?
So it's basically a sophisticated Wiimote.

On a conceptual level I feel like it takes the ideas behind the wiimote and evolves them in the most efficient and logical way. But the actual implementation of those ideas is different from the wiimote.

You could think of it as somewhat analogous to having an enhanced wiimote with six "cameras" instead of one, each facing a different direction, and "sensor bars" placed on all six sides of a room instead of just part of one wall. That's not at all how it's implemented though, and there are also some additions to this solution that aren't present in the analogy (such as giving each "sensor bar" some information about its own acceleration or orientation).


edit: The main breakthrough here, in my opinion, is in combining the right technologies in order to allow for a maximally cost effective solution. That's a trait many important engineering breakthroughs have in common ;)
 

Nzyme32

Member
Just read up on that article. Fascinating stuff.

The IR LEDs provide the start of a timing sequence. A microcontroller (attached to the photodiode) starts a counter (with fine-grained time resolution) when it receives that initial sync signal, and then waits for the X and Y line lasers to illuminate the diode. Depending on the time elapsed, the microcontroller can directly map the time delay to X and Y angular measurements. Using multiple photodiodes and knowing the rigid body relationship between them, the microcontroller can calculate the entire 6-DoF pose of the receiver.

One thing to note: I simplified this discussion a little bit. Like many IR systems, the LEDs and lasers are actually modulated (Alan said, "on the order of MHz"). This is useful for a few reasons: (1) to distinguish the desired light signals from other IR interferers such as the sun; and (2) to permit multiple transmitters with different modulation frequencies. This is a pretty obvious enhancement, but it muddles the layperson description.

It's so awesome when these elegant and scalable solutions to problems pop up
 

Supernorn

Chucklefish (Starbound)
Wow, does this put the other VR methods to shame?

I have tried both the DK1 and DK2 Rifts, and I got to demo the Vive earlier this year.

The Vive makes everything else look like a baby toy. I was seriously blown away.

I think there's some genuine questions as to how you transition the 1:1 movement to a proper game like an FPS, where you'd traverse long distances. All of the demos I tried were in spaces where you had free movement but weren't exactly covering large distances.
 
I think there's some genuine questions as to how you transition the 1:1 movement to a proper game like an FPS, where you'd traverse long distances. All of the demos I tried were in spaces where you had free movement but weren't exactly covering large distances.

People experimented with this, talked about it at the Vive VR Jam. Some had you always take an elevator, other made the room teleport/shift behind you, some said you could turn into a giant, leap to another part on the map, and get normal sized again. It definitely won't be solved in a traditional manner.
 

Miracle Chosuke

Neo Member
Interesting interview, ashecitism. Does anyone know if the base stations can be placed on the floor, or if they need to be mounted high up in the room? I feel like that's rather important for the practicality and ease of use of the system.
 
Good question, haven't seen anyone ask Valve that. This is just me guessing, be maybe if you tilted it so it looked upwards, I think it could work.

lighthouseslide1.png

so the opposite of this pic. Because the lower sensors could still pick up the lasers. I think.
 

Nzyme32

Member
Interesting interview, ashecitism. Does anyone know if the base stations can be placed on the floor, or if they need to be mounted high up in the room? I feel like that's rather important for the practicality and ease of use of the system.

I imagine it could cause a bunch of issues. You essentially increase the likelihood that you will occlude at least one of the sensors since your body is going to be at ground level
 

Raticus79

Seek victory, not fairness
Good question, haven't seen anyone ask Valve that. This is just me guessing, be maybe if you tilted it so it looked upwards, I think it could work.

so the opposite of this pic. Because the lower sensors could still pick up the lasers. I think.

I don't see any reason that it wouldn't work, but it would be much more likely to have blind spots. You'd have to make sure there wasn't any furniture in the way, no pets walking by, people watching need to be out of the way, no stuff could be put next to them on the floor, etc since it would break the tracking if both stations got blocked at once. It's also much more likely that your own body (or your chair) would block the line of sight compared to an elevated setup.

So, it's more hassle to set them up on the walls, but you could forget about them afterward, compared to having to be mindful of them with them on the floor (or even at eye level).
 
Valve filed a trademark for Chaperone

Hardware and software, sensors, and beacons for the detection and measurement of physical objects and the representation of such objects in virtual reality environments; Devices used for the detection and measurement of physical objects and the representation of such objects in virtual reality environments; Electronic apparatus for the detection and measurement of physical objects and the representation of such objects in virtual reality environments

http://tsdr.uspto.gov/#caseNumber=86558185&caseType=SERIAL_NO&searchType=statusSearch

from the hands-on impression this name came up when you would near the physical wall and a virtual wall would show up
 
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