Under water.

[Arthur Wolf]

Just curious, how well would a kinect work under water ?
Not at all / would lose precision / would require ajustments ?

Thanks :)

[William Cox]

IR is severely attenuated by water. I doubt it would work at all - maybe in a pool, but not sure.

If we could change the laser wavelength to 532 nm, then it'd be perfect for underwater.

-William

[Arthur Wolf]

even on small distances ? ( less than 1m )
given you can get a kinect to work for that kind of distances at all,
wich I'm not sure of ...

[Anthony]

i maybe wrong, i only have wikipedia to go by, but i believe for the
IR laser in the kinect to be eye-safe, it needs to be in order not to
burn your retina.
the reason its eye-safe is that the particular IR wavelength is
heavily attenuated by water and similar liquids like the fluid in your
eye.

I wonder if the defraction grating can be swapped to a different
laser,

quoted from wikipedia
"Certain infrared lasers with wavelengths beyond about 1.4 micrometres
are often referred to as being "eye-safe". This is because the
intrinsic molecular vibrations of water molecules very strongly absorb
light in this part of the spectrum, and thus a laser beam at these
wavelengths is attenuated so completely as it passes through the eye's
cornea that no light remains to be focused by the lens onto the
retina."

[Arthur Wolf]

me sad.
so no kinect+submarine+harpoon autonomous fishing machine :(
damn you infrared !

[William Cox]

The laser on the Kinect is near IR - probably ~800 nm. That can cause significant eye damage given sufficient power. The Class 1 rating is due to the limitation on power.

You may be able to get 1 meter of distance ranging in clear water, but I wouldn't get your hopes up.

If we changed the laser diode it's hard to say if things would continue to work because a) the diffraction grating is designed at one wavelength and b) the camera used to observe the light pattern is an IR camera - but it might have response at lower wavelengths.

-William

[derjoo]

cameras usually work on a quite wide range of wavelengths so i suggest that one would only need to change the IR filter which is in front of the camera.