From: "Jonathan Bromley"
Subject: Re: Lowest noise CCD readout.
Date: Mon, 6 Jan 2003 16:14:41 -0000
Reply-To: "Jonathan Bromley"
NNTP-Posting-Date: Mon, 6 Jan 2003 16:14:48 +0000 (UTC)
X-Newsreader: Microsoft Outlook Express 5.50.4807.1700
> I'm trying to make a star-tracker, that can see stars at video rates.
> (currently it's not good enough, using the stock electronics from a
> surveliance camera, I need about 6.5 times lower noise.)
> (the CCD is the ICX255AL, I don't know what the output circuit looks like)
I suspect the ICX255 is an interline transfer device, but if you have a
full-frame device then you could consider time delay and integration (TDI)
in which you move the CCD device, in the vertical scan direction, at the
same speed as the vertical readout is taking place. That way, you end up
summing all the optical contributions **into different pixels** and get
lots of SNR improvement. In practice that would probably mean
reciprocating motion, with some kind of linear encoder on the carriage
whose output could be used to generate the vertical transfer clock.
Could be a fun project. Depends critically on the stars staying
put for you, which is OK if it really is stars that you're tracking...
Jonathan Bromley, Consultant
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