Indefinite capture on PC camera?

I got a cheap usb PC Camera but I need a way of getting indefinite capture, as in I need it to keep the shutter open (it uses a cmos visual detector not shutters). How would I do that? I was using a software I downloaded free from the internet. setting a really slow frame rate doesn't work for this. What software should I use, and what would I need to do to get the indefinite capture?

Comments

[steveastrouk]

AH ! You MIGHT get away with frame stacking software to do this.

[Higgs Boson]

Where could I download/buy frame stacking software?

[steveastrouk]

Where have you looked so far ????

Try Registax for a start.

Bev at COAA has "Astrovideo" which is worth a look.

Steve

[rickharris]

Not sure I understand w=what your trying to do - Simply capturing images over and over will just lead to a white screen? won't it.

[Higgs Boson]

Well I am trying to perform the double slit experiment. the film that was used in the original experiment is no longer available, and I didn't want to dismantle a digital camera, so I decided I was going to use a webcam for the detector. in a completely dark box, when the photons hit the webcam's sensor, it should look like a white dot on the screen. the problem is you need to leave everything running for many hours to see the interference pattern. and if the camera is constantly starting new images, you would only see a white dot on a some of the frames. If you could "keep the shutter open" on the webcam, then the image that you see after the experiment should be all the photons that hit it throughout the entire experiment where if the camera was taking video, the image you see might contain a single photon hit. If there was a way to display every frame from a video on a single image, that may work but otherwise I would need the camera to be taking a single picture for many hours.

[steveastrouk]

If you're trying to do a really long exposure with a CMOS webcam, forget it, you need to use a CCD AND that needs to be cooled to <<-20C.

Frame stacking is the way to go.

Steve

[steveastrouk]

Not if he's using it for astro-imaging - up to a limit imposed by thermal noise anyway

[iceng]

+1 on thermal noise.

Lots of physics experiments take place in He cold :-)

[rickharris]

Interesting I hadn't thought of that. :-)

[iceng]

Some early cameras were exposed dynamic ram with a lens and
software to allocate the realignment of the dispersed pixels into a
meaningful image that was black and white depending ( 1 or 0 ).

The fun part of the imaging software was you could specify how many
pixels were to be white ( say 45% )  and the clock would speed up or
slow down to arrange the ratio by counting the white zero pixels .

This automatic imaging exposure control aimed out a window would
produce a fascinating continuous view of my neighborhood  that
changed gradually with day night transition.

A

[steveastrouk]

There's the famous "Steve Chambers" mod, but that needs a CCD based camera. Take a look here http://www.qcuiag.org.uk/ for some more information on camera modding.

Some cameras can be software controlled for exposure, some need hardware changes.