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Cooling a Digital Camera?
thusson asks: "I work at a lab doing intrinsic signal imaging of cat and mouse visual cortex (brains). We are using a Dalsa 1M60P camera, and we want to cool it about 30-50 degrees C to improve picture quality by reducing noise. Does anyone have any suggestions about how to do this? So far, heat sinks have helped but only by a few degrees. I figure the overclocking community is a good place for novel ideas."
What should you be cooling? How are you measuring your temp? Answers to these questions will drastically change the answer.
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30-50 degrees Celsius?
#1 - Is your claim valid
#2 - Will the camera work at that temperature
#3 - Try some liquid nitrogen. Or, some spray dusters turned upside down.
A lot of people people use these to cool there optical sensors for telescopes.
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we want to cool it about 30-50 degrees C
So far, heat sinks have helped but only by a few degrees
What makes you think that heat sinks will lower the temperature by 30-50 C? At best, heat sinks will lower the temperature to that of the surrounding room.
If you want something cooler, you'll need to use Dry Ice or refridgeration or some external input.
Peltier elements are the way to go here. They're small, accurate and powerful. Anything you want in a scientific environment.
I do research in a neurobiology lab and for one of our setups we water cool our camera. I just looked at it now (it is not my setup), it seems to run water from a nearby pipe into a specially made heatsink mounted to the back of the camera and then outagain towards another pipe.
As a number of people have correctly pointed out briefly, Peltier effect devices, also known as thermoelectric coolers (TE coolers) are the most likely way to accomplish this. There are companies (Products for Research, e.g.) that specialize in pre-packaged TE cooling units for various types of equipment. The basic coolers almost all come from Melcor.
With very careful design and construction, you can use a multi-stage TE cooler to get more than a 50C offset from room temperature. It requires careful attention to insulation, and to heatsinking of the first (hottest) stage.
Before you go cooling your camera, though, you should check whether it is designed to run cold. Any device, cooled to -30C (or even to 10 degrees below room temperature, in Tennessee humidity) will start to condense water. To run a camera cold, it must be designed to be water-tight, and must almost certainly have a dry-gas-filled double window (or vacuum double window) on the front, with the outer window heated to prevent fogging.
Overall, unless the camera was specifically designed to be cooled, you may be better off buying one that is appropriately designed, unless you have a lot of time, money, and expertise to put into the engineering. Certainly talk to the manufacturers of the camera you have before you start cooling it, and see if they sell a kit cor conversion.
Peltiers are probably your best best. You'll need to mount heat sinks on the hot sides to radiate off the waste heat, but you can get a good 60-70 C temp difference between the hot and cold sides.
There's a good example here
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But I will try:
There are two solutions to this problem. The first, is to cool your sensor like you asked. A peltier cooler in between the sensor and the heatsink is the only way to do this. A heatsink will reduce you to ambient temperature at best. If you want to go below that, you need a peltier cooler at least, or something much more exotic like a compressor-based refrigeration unit, evaporative cooler, or liquid nitrogen cooling.
Alternately, you could use a CCD with a cooler already built in, such as those from Santa Barbara Instrument Group.
Finally, you could simply use a sensor that isn't so noisy. All the digital SLR cameras nowadays use CMOS sensor technology, because it's bigger than CCD primarily, but it also has a lot less noise since it isn't crammed into such a small space.
Another approach often used by astronomers is to take the noisy CCD, do an exposure of a given length, then cover it so no light can reach it, and take another exposure of the same length to create a "dark frame" that contains nothing but noise. The noise in both images will be approximately equal, and can be subtracted out using photoshop or similar software, resulting in a very clean image.
Random and weird software I've written.
Why not just throw it in the freezer for a few hours before the experiment. As long as the experiment isn't too long, you should be able to take it out, use it, and return it to the freezer for the next round.
It's good to use your head, but not as a battering ram.
It is a Peltier device. It's real. It works. One side gets hot, the other cold. It's just a solid state heat pump. Do your own googles, try "thermoelectric" if "peltier" doesn'te net enough, for further info.
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Many people have mentioned that you can use peltiers to cool the sensor below room temperture, This is probably the most cost effective way to do it, but since this is /., there's another really cool way to do spot cooling. If your lab has a clean source of compressed air, check out exair.com. These things are called vortex tubes, and can create incredible temperature deltas, that are ideal for spot cooling, provided that you can supply the amount of air it requires. I've been told that it's actually relatively quiet given how much air it consumes, but i have no personal experience with them. just make sure you keep the exhaust end away from anything you don't want to melt. I woulda used it to make coffee while cooling my processor, but not everyone can afford a pump and a tank that can maintain that kind of airflow at 100 PSIG. Oh, one other thing... have you considered the potential issues w/ cooling the chip to those temperatures? I'd imagine condensation would kill your image quality, and depending on how well the boards are made, the solder joints may develop stress fractures. I remember using cold spray to cool PCB's to make sure there aren't any cold solder joints on PCB's we test. Oh yea, you could also use cold spray instead of the votex tube, but something about that stream of hot exhaust seems strangely apealing.
My father is an amature astronomer and bought a CCD camera kit this Richard Berry guy put together. The CCD chip is mounted on an aluminum block that fits inside an aluminum "eyepiece". There is a peltier device mounted (cold side) to the bottom of that. Then the hot side of the peltier has another aluminum block mounted to it where water flows through.
Just go lookup "Richard Berry CCD camera kit" in google and you could probably find something.
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