Posted by
Gerhard Holst on
URL: http://confocal-microscopy-list.275.s1.nabble.com/seeking-suggestions-on-new-sCMOS-camera-tp7579501p7579513.html
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Hello Zulin,
maybe you should consider, as I mentioned, that your emCCD camera, in case it is a back illuminated emCCD sensor, has a higher quantum efficiency, which would result it 30% more signal for the same amount of photons.
Second if you compare, please make sure, that the same amount of photons reaches the same amount of pixels, for example, if you use the same optics and image your sample to a camera with 12µm and to a camera with 6µm pixels, then the amount of photons hitting the 12µm pixel will be shared by 4 pixels on the camera with the smaller pixels, which is not a characteristic of the sensor but the optical situation. And if you provide only a 1/4 of the signal the corresponding SNR will be smaller.
Further, in your noise calculation, you only consider the spatial noise, meaning the inhomogeneity between the pixels, the temporal noise (from image to image) is neglected. If this is the relevant noise to you, that's ok.
But anyway, you should use the camera which fulfills best the requirements for your application, nothing else.
with best regards,
Gerhard
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Dr. Gerhard Holst
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PCO AG
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Von: Confocal Microscopy List [mailto:
[hidden email]] Im Auftrag von Zulin Yu
Gesendet: Donnerstag, 17. Januar 2013 04:41
An:
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Betreff: Re: seeking suggestions on new sCMOS camera
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Hello All,
Thanks for all replies!
Here is a quick summary wrote by my senior colleague and I hope his summary
will clarify some questions. "I have been using the standard deviation of a dark
area as the noise, the average of the dark area as a background and the average
of a high signal area as the "max" (SNR=(Max-Min)/noise). I have checked, the
min and noise in min figures are the same in the completely dark region of my
sample as they are in a truly dark image. The gain on the EM is 255 and the
amplifier is 5. I am guessing a total gain of 550-750 which puts the photon count
per pixel somewhere between 40-60." Under the condition of 40-60 photons,
EMCCD SNR is 46, much higher than 12 on sCMOS.
I had a phone call with Hamamatsu technical support today, based on their
experiment, the EMCCD should have a higher SNR once the signal is higher than 6-
15 photons. However, our results have big disagreement with them. Something
must be wrong, either our measurement or either the camera. So we send our
original data to Hamamatsu for further investigation. I will keep you updated once
I hear something from Hamamatsu.
Ps, the EMCCD we used is also from Hamamatsu (c9100-13).
Thanks a lot, Zulin