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Posted: 3/5/2013 8:34:13 PM EDT
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Just a small note - Canon have introduced new low-light arrays that are aimed at recording color video. http://www.canon.com/news/2013/mar04e.html It's a nice idea and looks like it might work quite well. It's at about Gen1 level, but that's in high resolution and full color, so that's quite a technological leap. Regards David
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So what they did is increasing the sensor effective area to gather more light? IIRC, CCD's pixel spacing is in single digit microns (I only worked on FLIRs, mostly cooled) and the integration time of these CCDs are still in microseconds (due to pretty much no pedestal in VIS). I'm guessing they also up the integration time, so they fill up the quantum well or before it smears?
Or is this a new doping technique of the CCD itself? I didn't see this mentioned. I see the low-noise ROIC (read-out IC) part, and bigger sensor effective area - I mean these are obvious things to me. They could also lower the noise by cooling the ROIC. |
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Quoted: So what they did is increasing the sensor effective area to gather more light? IIRC, CCD's pixel spacing is in single digit microns (I only worked on FLIRs, mostly cooled) and the integration time of these CCDs are still in microseconds (due to pretty much no pedestal in VIS). I'm guessing they also up the integration time, so they fill up the quantum well or before it smears? Or is this a new doping technique of the CCD itself? I didn't see this mentioned. I see the low-noise ROIC (read-out IC) part, and bigger sensor effective area - I mean these are obvious things to me. They could also lower the noise by cooling the ROIC. The article doesn't say much, but I'd go with backlit CMOS of larger surface area from what they do say. Cooling is impractical for the modern "turn on and shoot" camera users. I'm still waiting to see the quantum-dot enhanced CCDs but have yet to see it return to commercial use since they invented it, though it looks like they are using that in new out-of-band imagers. Of interest was that the functional gain levels should be about the same as Gen1, so it would probably make an excellent cascade tube with a Gen1 image intensifier attached via FO plate. If that's the case, it could be quite a useful technology and may well find industrial use as well. Gen1 is fairly light too, so a hybrid gen1/digital camera would be very effective for low-light imaging and recording purposes. Like an astroscope with just a Gen1 as a first-stage, but coupled to avoid light loss. I keep on waiting for someone like ATN to realize this is viable - that a low-light CCD hybrid-coupled with a Gen1 can compete with Gen2, yet probably costs less than $100 to manufacture a basic system. Regards David
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| The sony exview cameras have been around 7-8yrs. They work very well, a person 100ft away smoking a cigarette on my cameras look like they have a road flare held in thier mouth . The ir from the cigarette looks like a fire ball and you can't see the head area. They can see the 940IR from the yukon unit I have like a spotlight. The 780nm 150mw laser works great for a spotlight using these bullet cameras. I got them from ebay for 109.00, they claim to be .0003 lux. I can see better with the cameras on the tv monitor then looking out the window with naked eye. A car's brake lights look like high beam head lights. I have had these 6+ yrs 24hrs a day 7 days a week, still working. Far from the resolution and color, that canon is developing. But the gen1 ccd combo, should out perform either technology used separate, at a fraction of the cost. Maybe someone will market one? |
| David - thanks for that. Indeed, it is good that someone finally does a dedicate sensor for night sensitivity. It's better than someone taking regular CCD sensor and up the integration time. Of course, with larger sensor area, you also increase the optics size. IIRC, quantum efficiency of the CCD is pretty high already. |
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