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Sensitive color cameras

 
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Lightningwizard



登録日: 2007.10.19
記事: 154

記事日時: Mon Dec 28, 2009 4:40 am    記事の件名: Sensitive color cameras 引用付きで返信

I was hoping to find a color camera with high sensitivity and >1 megapixel without interlacing, but I guess the time hasn't come yet Wink I was browsing many options.
I looked at the Imaging Source 1 megapixel camera review by SonotaCo, but if the black and white version is not sensitive enough, the color version must be worse. Probably astronomical cameras of more than $2000 may be good enough, but have too slow frame transfer rates and the cooling you pay a lot for is not effective for short exposures (readout noise and photon shot noise are the problem, rather than dark current).

I have seen Ferruccio Zanotti's gigantic jet, sprites and even elves captured by the normal video size color Mintron MTV-62V6HP EX (1/2" sensor). It looks actually pretty good in terms of sensitivity and S/N. The GJ was even overexposed! For some purposes, I like the frame integration mode. Examples: http://www.nachtleuchtende-wolken.de/galerie.html (the videos indicated as "webcam")

Just found this one:
http://www.samsungcctv.com/prd/pro_view.asp?pro_uid=4144&cat_uid=14&cat_biz=ctv&cat_lev=AA
and http://www.cam-techsecurity.co.uk/cctv-new-the-best-cctv-camera-yet
It seems very similar in functions, but can also operate in B/W and has 3D noise reduction. While this might sometimes affect small details, it could be useful since UFOCapture detection sensitivity is limited by noise level. Mintron and Samsung products look quite similar. The 1/2" Exview color sensor must be the same, so base sensitivity should be the same except for the other electronics and DSP.
Interesting.

Oscar

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Weather & Photography
http://www.lightningwizard.com
EuroSprite blog:
http://eurosprite.blogspot.com
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SonotaCo
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登録日: 2004.08.07
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記事日時: Mon Dec 28, 2009 12:02 pm    記事の件名: Re: Sensitive color cameras 引用付きで返信

Hi Oscar
Thank you for info.
May be the CCD is same type as recent WATEC 250D2(1/3").

... Idea your message drives an idea of new type of UFOCapture, UFOCaptureFS (frame stacking Exclamation )
Frame stacking on PC -> Time domain noise reduction -> improve S/N -> improve the motion detect sensitivity.

I was thinking that frame stacking is not good for motion detection. Because it brightens the background but not the moving or momentary events.
But if an object is bright enough like the GJ , stacking of a few frames may contribute the motion detect sensitivity.

Well,,, dream is too much always .... Wink
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Lightningwizard



登録日: 2007.10.19
記事: 154

記事日時: Mon Dec 28, 2009 2:09 pm    記事の件名: 引用付きで返信

Hi SonotaCo,

yes interesting, stacking a few frames may work to increase S/N ratio (maybe Detect Level is reduced by 1/2 for two frames, 1/3 for 3 frames?). But noise only interferes with detection of faint objects, with a brightness change close to that of the noise background. So, it would work when the noise reduces more than the contrast between background and object. For example, if noise level was 30, it may reduce to 15 by stacking two frames, while the background luminosity doubles. But it is not so bad as long as the object to background difference is greater than 15. The stacked frames with and without object become more and more the same luminosity but there should remain some pixel value difference. But the noise may (or may not) be reduced faster. It could be worth a try Smile

The camera has noise reduction in its DSP. It could work similarly to a filter "Noise Reduction Suite (NRS)" I downloaded for VirtualDub. It smooths out the noise over time and hardly affects a sprite, depending on the spatial criterion. Could be interesting to have this before the capture stage.

Happy holidays!
Oscar

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http://www.lightningwizard.com
EuroSprite blog:
http://eurosprite.blogspot.com
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