Re: Idea exploration - Image stabilization by means of software.

>

>>Are you taking pictures of stationary things from a stationary camera? That's >>what the astronomy case involves. But since you are concerned with a moving >>camera, I assumed you were talking about pictures taken with a hand-held

camera.

If one scaled this down so that the "short" exposure time is in >milli-seconds or even micro-seconds depending on what the sensors can >do, then one can do the same thing just at a much faster scale. >What is the minimum exposure time for a current CMOS sensor before one >just see the inherant sensor noise ?

Get real. You've got to read out the sensor, as well as merely exposing it. Unless you have a highly integrated CMOS imager with piles of memory on it, there is essentially only one (*) serial data path out of the device and you need to squeeze all the pixels through that. Shortening the exposure of a CCD sensor is easy; it's done all the time to control exposure time. But it is *very* hard to get the image OUT of a multi-megapixel CCD in less than a few milliseconds.

There is precisely one way in which you CAN do this: it's called "Time Delay Integration" or TDI and it's been widely used for hi-res military sensors for ages. If you can arrange that the motion is at a constant speed along the sensor's Y axis, then you can organise the sensor's vertical shift clock so that it keeps in step with the motion, and a fairly long exposure can be perfectly sharp. Brilliant for taking aerial reconnaissance photos from a 'plane in flight. But it needs lots of smarts in the motion sensing and the camera readout electronics.

If I read the OP's idea correctly, he wants to correct the picture for motion blurring after it's been exposed. This is perfectly possible if you know the exact behaviour of the motion. The OP should find out about "deconvolution". To take a simpler example: Suppose you have a stream of data, and before you get to see that data you know that it has been processed by a moving-average filter. How can you reconstruct the original data points, if you know the exact form of the moving-average filter function?

(*) Some sensors have multiple serial output paths - see Dalsa's offerings, for example. The number of paths is never more than a small handful, though. Broadside readout of the lines into local on-chip memory is the only hope.

--
Jonathan Bromley, Consultant

DOULOS - Developing Design Know-how
 Click to see the full signature
Reply to
Jonathan Bromley
Loading thread data ...

OP should look up "deblurring" algorithms. Ofcourse it helps to shoot a laser beam into space to get that vector.

Also Micron (the DRAM guys) are in the cmos image sensor biz both commodity VGA camera stuff and apparently high end very high speed imagers that scan orders faster IIRC in the 1ms range.

I am sceptical myself about cmos in general having bought some of that low end junk but Micron seem to have made real progress in bringing cmos upto ccd performance plus the integration. They bought out several imaging companies.

I also looked at a job with a high speed ccd outfit, theres people out there trying to do 4kx4k in 1 ms with processors on the backside of the chip massively parallel, very interesting, very big $.

perhaps that will help.

johnjakson at usa dot com

Reply to
JJ

References: In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Message-ID: Lines: 15 Organization: Arcor NNTP-Posting-Date: 19 Jun 2005 12:22:17 MEST NNTP-Posting-Host: 1d91000a.newsread4.arcor-online.net X-Trace: DXC=5CoB`PX@=ZFo47S\@TX3oE:ejgIfPPldDjW\KbG]kaMH]kI_X=5KeaFeAjINmPAh`M;9N1HBTl4dAd>T`[6A^LlM5HZVN0nNn3F=]]5jE@XJPD X-Complaints-To: snipped-for-privacy@arcor.de Xref: newsgate.xilinx.com comp.arch.embedded:162490 comp.arch.fpga:77171 comp.dsp:133270 sci.image.processing:27813

Kris Neot wrote: [...]

How do you distinguish between motion due ti shaky hand and motion due to external "object" motion?

I mean, if a take a picture of an highway, there is a lot of "shakyness" in the subject already...

bye,

--

piergiorgio
Reply to
Piergiorgio Sartor

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.