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Comment by sillysaurus2 | Hacker News Reader

Unfortunately, eye tracking is only possible in broad strokes, not fine detail, and certainly not for tracking fast-moving small targets across the screen in a realtime action game. There's pretty much no such thing as a smooth eye movement; your brain tricks you into thinking your eyes are moving smoothly when they're not. http://en.wikipedia.org/wiki/Saccade

I wanted to use my eyes to create 3D models via eye tracking. Looked into it for about a week before concluding it was probably impossible, or at least way less accurate than good old-fashioned hand movements.

Dunno what the Oculus guys are doing with gaze detection, but I doubt they're doing fine-grained detection such as being able to pick out a particular target with your eyes. (I would love to be wrong about this! That'd be an awesome feature. I just doubt whether it's technically possible.)

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This is mostly true, but our eyes can also do "smooth pursuit"[0]. You can lock on to a moving object and follow it smoothly.

I've trained myself to be able to do this with vertical lines, like window blinds.

[0]: http://en.wikipedia.org/wiki/Smooth_pursuit

The Oculus doesn't have gaze detection built in right now, but there are actually at least two consumer eye tracking products coming out (focused on gamers). One is the Tobii EyeX http://www.tobii.com/en/eye-experience/ and the other is the Eye Tribe Tracker: https://theeyetribe.com/

Both are about $100 and have dev kits/SDKs, although I haven't looked closely at either.

Thanks for the pointer to Eye Tribe. I ordered an EyeX but hadn't heard about them. Eye Tribe seems more developer friendly, with tech specs front and center.

Isn't the cannon on SA and Israeli helicopters eye-tracked? (I think the Apache is helmet-tracked, but its also a much older system)?

I can't find it by googling, but a long time ago I used to read far too many Flight magazines.

From eye tracking can you infer where the user thinks they are looking? I.e. recover the illusory smooth eye motion I perceive when tracking a moving cat.

If you are tracking a moving object, you are using 'smooth pursuit' - your eye movement actually is smooth, not illusory. If you're moving your gaze along a stationary object, that's when you get saccades, a series of short, jumpy movements.

I think it'd be impossible because when you think you move your eye, your brain is essentially just moving a bitmap image of what you're looking at around the center of your vision. E.g. look at the word "sillysaurus2" above my comment. Look at the 's', then look at the 'y' -- keep looking back and forth. Your eye likely isn't moving at all, even though your focus of vision does. It happens mentally rather than physically.

I recorded a video of myself doing this, and I certainly can't see any obvious eye movements. But if I think about the number of degrees that my eye is shifting between the 's' and the 'y', it's probably one degree at most. It's not clear to me that even if my eye was moving I would be able to register that movement in a video.

I'm assuming you've seen some peer reviewed research that fixed peoples' heads and used high resolution eye tracking to support your hypotheses, though?

I tried what you said and I could definitely feel my eye moving. Is that being synthesized by my brain?

Indeed, it is. Strange but true.

The way to convince yourself your eyeball isn't moving is to touch your actual eyeball with your fingertip -- like press lightly against the left corner side of your left eyeball with your left index finger -- and then switch your gaze back and forth between the two letters. As long as your viewing distance is correct, you won't feel any movement. (You may have to back your head away from the screen. I'm viewing from a distance of arm's length.)

On the other hand, if you look back and forth between adjacent words, then you can feel physical eye movement.

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