Slashdot Mirror
Ultraviolet Digital Cameras
An anonymous reader wrote in to tell us that "Scientists at North Carolina State University's Solid State Physics Laboratory say they have built a
camera that can take pictures of anything that emits ultraviolet light." And we'd like to announce an update to the RobCam: I think Hemos and I will be wearing a lot more white.
Where I work we have digital cameras* that take pictures in 3D and work with gamma rays. And a camera that constructs 3d images from radiowaves in a magnetic field.
PET and MRI (aka NMR) are old technology tho, PET's resolution being limited to ~8mm iirc, due to the fact that a positron has to drift a certain distance before annihilating (Statistically speaking). MRI's drawbacks are that you cant have any metal in the subject.
Oh, and they're both expensive
(* If you define a digital camera as something that creates images from life)
-Yarn - Rio Karma: Excellent
"All stars emit ultraviolet light, so compact digital cameras sensitive to that wavelength could open a new window on the universe."
Erm, yeah, like I didn't know that?
More to the point, what is a digital camera, at eg 1152x864 resolution, going to see that the big boys can't now?
I think the whole thing is just a tad simplistic but ludicrously optimistic, typical journalist-meets-brains syndrome...
~Tim
--
Rushing on down to the circle of the turn
...they're also sensitive to IR - try aiming your TV remote at one. Lots of fun can be had confusing people by making displays out of IR LEDs so that they can only be seen on a monitor! (incidently, anyone ever tried saturating their car/bike number plate with IR to defeat speed cameras? ;)
[Happosai]
That's why they're usually said to cut the "haze" on overcast and hazy days -- the lower light levels makes it more noticable. Its also a matter of what colors the light registers as on the film as compared to the visible-light color of the same object. Sometimes it'll just minutely shift the color and fuzz the outlines. How stopped down the lens is, what kind of lens it is and factors like that also affect it. You'll almost never notice it on a handheld shot. But if you shoot a scene on a more overcast day on a tripod with and without the filter, depending on the camera it can be very noticable.
The more glass there is in the lens (the more elements) you also strip out more and more UV.
Do some searching on the net, I've seen a half-dozen sites with ultraviolet galleries.
Most standard chemical-based film stock is also ultraviolet sensitive. That's why even novice photographers know to put a UV filter on the lens, because lenses focus the ultraviolet at a different point than the other colors (and ditto with infared, although non-infared film is rarely very sensitive to infared, whereas most film is fairly sensitive to ultraviolet), and you get a hazy look to the film -- the haze is just a blurry exposure of the scene in ultraviolet.
For any amateur shutterbugs out there, if you can find a quartz lens that fits on your camera (they're very hard to find and VERY expensive unless you get really lucky), you can get filters to put on the lens that will cut out all the visible light, letting the ultraviolet through, and you can actually shoot very interesting photos in UV using standard film. Exposure times are longer, and you've got to guess on the exposure because meters won't read the light levels, however.
The device itself has a LONG way to go before being useful for a lot of applications that need more than a simple 'detection' of UV. The article says that the chip is an array of 1024 detectors (ie: a 32x32 array) which is hardly enough for any serious visualization usage. It is a good first step on the way to 'consumer grade' UV detectors which are good enough to be considered cameras.
Right now, it's just a small slab of detectors a few dozen on a side. While even at that size it could be very useful in certain applications (I've got my doubts about the weld examination if one only has a 32x32 pixel window to view with!) it won't be really widespread-useable until there's at least a 256x256 (or maybe 300x200, given digital's trend towards 3x2 ratios) pixel device. Then I expect you'll have spy shops all across the net selling UV-enhanced spy cameras. ;)
--
rickf@transpect.SPAM-B-GONE.net (remove the SPAM-B-GONE bit)
"People will pay big bucks for the luxury of ignorance."
http://www.discovery.com/cams/sun/sun.ht ml
Although they admit that it's actually four separate cameras, each just capturing one wavelength of UV light - so presumably using different technology?
-=Best Viewed Using [INLINE]=-