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Re: Video Frame Grabber (fwd)



---------- Forwarded message ----------
Date: Sun, 09 Sep 2007 10:52:37 -0700
From: Jim Lux <jimlux@xxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Video Frame Grabber (fwd)

Tesla list wrote:
> ---------- Forwarded message ----------
> Date: Sun, 09 Sep 2007 10:14:51 -0300
> From: Antonio Carlos M. de Queiroz <acmdq@xxxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: Video Frame Grabber (fwd)
> 
> Tesla list wrote:
>> ---------- Forwarded message ----------
>> Date: Sat, 08 Sep 2007 01:53:40 +0000
>> From: Sparktron01@xxxxxxxxxxx
>> To: Tesla List <Tesla@xxxxxxxxxx>
>> Subject: Video Frame Grabber
>>
>> Folks
>>
>> I was reviewing recent magnifier video work at a Alex Tajnsek's shop,  The video 
>> is from my Digital Camera (AVI, 30FPS), when I realized having a frame grabber 
>> would be extremely useful to monitor streamer propagation, system
>> malfunction, etc.  OK, it is not a streak camera; but for the cost (FREE) and the
>> speed (33ms /.frame, 2 AC cycles), has been very enlightening and useful.
>>   
> I imagine that you can do the same with any digital video editor, 
> including Windows Movie Maker, that is part of the Windows
> operating system.
> 
> Antonio Carlos M. de Queiroz
> 

Another interesting strategy, to get finer resolution, might be to use 
multiple cameras/recorders looking at the same scene.  They will tend to 
have different "phases", so by combining the various streams, you could 
get more data points.  With the advent of inexpensive standalone video 
recorders (think in terms of cellphones that record video), using solid 
state shutters with fast times, this might be a way to get a "poor man's 
framing camera".

You'd make sure there's something in the field of view that could allow 
measurement of the skew between the frame streams (a spinning disk at 
1800 rpm could do.  So would some LEDs hooked up to a counter at a 
sufficiently fast rate... I've used both)

Given that TCs are pretty bright, you could easily build a multiple beam 
splitter with something like sheets of glass, or, perhaps, sheets of 
saran wrap on a frame to make a pellicle (so that you don't get 
reflections from both surfaces).

I think getting 1 ms resolution wouldn't be out of the question.