

Xbox Kinnect user experiencing an afterimage. - piaskal
http://gaming.stackexchange.com/questions/13713/anyone-experiencing-vision-problems-from-xbox-kinect-laser

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burgerbrain
I am willing to bet that if these people _didn't_ have some understanding of
how the kinect works, they would not be experiencing this. Kind of similar to
how small towns will occasionally complain about radiation from newly
installed cell-towers, only to later realize the tower hasn't even been
powered up yet.

As I understand the kinect's operation, it sends out a grid of dots, each dot
being spread out by a few inches or so by a few feet away. In order to get a
grid after-image, _assuming that IR could do that_ , you'd have to be inches
away from the device so that several different beams were all entering your
eye through your pupil.

Now, it's possible there is something actually going on here, but my money is
on psychosomatic. Seems _way_ more plausible to me.

~~~
Someone
_In order to get a grid after-image [...] you'd have to be inches away from
the device so that several different beams were all entering your eye through
your pupil._

Not necessarily. Kinect beams could reflect of your room onto your monitor,
and back onto your retina. I think you might be able to achieve an afterimage
in a laboratory, if you tried really hard:

\- find some material that is fluorescent in visible light when irradiated by
the IR that Kinect emits

\- fill your room with it.

\- seriously darken your room.

\- play a game that has a very dark screen.

\- stare at the screen for a couple of minutes while Kinect is active, keeping
your eyes focused on one spot.

Of course, all of these are unlikely to be applicable here. Also, you will
probably have lots of trouble finding that fluorescent material, if it exists
at all; IR light is lower-energy than visible light, so the material will have
to do multiple-photon absorption.

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drivebyacct2
None of that changes the fact that this is IR.

And I still find it impossible to believe that "spots resemble a vertical or
slightly diagonal line and really resemble a sort of one dimensional test
pattern (with various symbols, kinda like various geometric shapes). " would
be visible via coincidence.

Psychosomatic. All the way. (I personally believe OP is a troll).

~~~
Someone
I wasn't attacking the conclusion, but only pointed out an error in his/her
logic.

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wccrawford
Considering that you can put on night-vision goggles and see the pattern that
a Kinect puts out, and it's just dots, not shapes, I seriously doubt this
guy's problems are actually from the Kinect.

~~~
eekfuh
You can also just your digital camera, my iphone 4's cam picks it up (it comes
up as just normal white light).

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dhughes
I thought most digital cameras and webcams have IR filters.

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kgc
For comparison, here's a youtube video of the dots the Kinect projects.
[http://www.youtube.com/watch?v=sM2-JQtd2Oc&feature=relat...](http://www.youtube.com/watch?v=sM2-JQtd2Oc&feature=related)

I think the "test pattern" is in the poster's imagination.

~~~
pontifier
If you'll notice at the end of that video, the projector seems quite bright.
If it is effecting the user's vision, a pattern could be because of eye
motion, not the actual pattern projected.

I worry permanent effects of bright IR sources myself... I tend to avoid
looking at Sick or Velodyne scanners when I'm around them too.

~~~
jonah
Lidar scanners use IR lasers. AFAIK the Kinect uses IR LED which wouldn't be
nearly as harmful.

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meatsock
all sorts of afterimages are both plausible and common after looking at any
sort of bright screen, after strenuous activity, or a combination of both.
question is phrased as 'is this common and annoying thing about the world
related to a new tech fad?'

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modeless
I'm sure it's not related to this guy's problem, but I was surprised to find
that Kinect puts out some visible light; you can easily see it when looking
directly into the emitter, and if you get close enough (think centimeters) you
can actually see (what I assume is) the dot pattern.

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sliverstorm
If you're worried, just get some sunglasses that can filter out infrared

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ams6110
Sunglasses filter UV. Off the opposite end of the visible spectrum.

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sliverstorm
Ok, so they wouldn't be called sunglasses. Either way, they have to exist
somewhere. I'm pretty sure welder's masks block IR.

~~~
Natsu
A welder's mask is much too dark to play a game with.

There are, however, IR cut-off filters. They're used in photography. See:
<http://en.wikipedia.org/wiki/Infrared_cut-off_filter>

~~~
ique
There are also sunglasses that filter out IR only, we wear them in the laser
labs in school all the time.

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binaryfinery
/world runs out to buy kinect just to be able to participate in class action
suit.

