Re: [MLUG] Followup on WebCam.

[vapor <EMAIL:PROTECTED>]

It is a result of the jpeg.  Unfortunately, there is no one standard for 
lossless jpeg... there's 3 different standards if I recall correctly, 
and the ISO standard is the only one that is truely lossless.  Even so, 
to get lossless out of the image you need to decompress it back into a 
truely lossless format (not jpeg).  The ISO standard only works well 
with smoothly-changing-in-tone images and still typically compresses the 
shown image by 2:1, which I would guess is what is happening as 
"HamsterCam.jpg" is only 77k.  There's no real point to having a 
lossless jpeg as you still need to decompress it to utilize the data 
available.

Regards,
Zach

Christian M. Cepel wrote:

> http://HamsterCam.bramblethorne.org/
>
> Its been live for about a week, and underwent the normal few days of 
> shakedown for any new gadget.  Its proving popular with the 'hamster 
> community' :)
>
> Hardware:
> Ended up getting a Logitech Messenger IM cam.  Not really happy with 
> it, but considering I bought the $20 off brand and then had to return 
> it and came home with something with true 640x480 CMOS 30fps, I guess 
> I didn't do too badly.  The one thing I cannot figure out is why if it 
> takes at 640x480 CMOS TRUE, why I'm seeing macropixeling in an 
> uncompressed image.  Here's the thing.  I would expect 640x480 
> distinct pixels, but I do not expect them to be grouped  and aliased 
> into little blocks of 64 pixels, 8 per side.  Here's what I mean.
>
> http://hamstercam.bramblethorne.org/HamsterCam-Macropixel.jpg
>
> Anyone know why this is?  I'm considering trying a webcam in linux 
> just to see if its something other than hardware.
>
> Wife doesn't want to leave the machine in Linux all the time so was 
> forced to find Windoze software to drive it.  Ended up using Active.  
> Fairly happy with it except that it won't do incremental numbers on 
> the FTP setup with the oldest being deleted, keeping only the newest X 
> shots.  Came with a slim little Java applet that I will keep even if I 
> switch software later on.  Would be happier if it (or the camera 
> hardware) would allow 90deg rotation instead of just 180, and if one 
> could set multiple events of the same type (multiple FTP 
> destinations/tasks).
>
> Anyways...



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