Re: [APML] OT: Webcam Lunar Mosaic

[Juan Conejero <skycad@ctv.es>]

Thank you Jose.

For AVI video capture you need a reasonably fast computer, especially 
regarding disk i/o. What is really important, more than processor speed, is 
disk write transfer rate. Your hard disk will literally be eating tenths of 
megabytes during video capturing, and no frame should be dropped at a rate 
of at least 15 frames per second, better 20 or higher. My laptop is a Sony 
Vaio PIII/650 with a 20 GB IBM Dara hard disk and 128 MB of RAM. It works 
fine when I have about 8-10 GB of properly defragmented free space. You can 
find this laptop or similar units in the 2nd hand market, I think.

For seriously processing astronomical AVI videos, use the fastest and 
biggest thing at hand, as a rule of thumb. Again, fast disk i/o, huge RAM, 
and high RAM transfer bandwidth is what really counts.

BTW, I have reprocessed the mosaic. Here it is (1.9 MB):
http://astrosurf.com/pleiades-ap/20030409/mosaic-L-curves-atw.3000.jpg

Regards,
Juan Conejero.

At 20:27 24/11/2003 -0500, you wrote:
>awesome Juan. I am thinking of buying a web cam to work with it but I dont 
>have
>a laptop . In case I decided to buy a second hand one with th minimun
>requirements to work with the webcam, do you know which are the minimun
>requirements of a laptop to work with the webcam and handle all the processing
>software and the AVI videos required?
>Many thanks
>Jose Benito
>Madrid
>
>Juan Conejero escribió:
>
> > Hello,
> >
> > It has been a long time since my last posting here; now I come back with a
> > new lunar mosaic. This is definitely off-topic, but I hope you'll like to
> > have a look at it.
> >
> > You can see a reduced version here (1.6 MB):
> >
> > http://www.astrosurf.com/pleiades-ap/20030409/mosaic-rgb-atw.3000.jpg
> >
> > Details:
> >
> > - Philips ToUcam Pro webcam, unfiltered.
> > - Meade LX200 12", prime focus (f/10)
> > - AVI video capture with K3CCDTools 1.0.6
> > - Video frames aligned and stacked in RegiStax 2.1.13.0 beta
> > - Mosaic composed in Photoshop 6
> > - Image restoration and noise reduction by A Trous wavelets processing done
> > in Pleiades PixInsight 1.0.0.33 beta
> >
> > Some facts:
> >
> > - Mosaic composed by 50 subimages
> > - 4651 video frames used, about 40% of total frames captured
> > - 4.9 GB of raw data
> >
> > I took the original AVIs on a good and steady night, past april 9, and they
> > have been waiting to be processed until now. Seeing was reasonably good
> > (8/10), though not spectacular. I tried to do my best to keep color data as
> > accurate as possible. I "calibrated" the camera with a white source before
> > taking the videos, and carefully planned exposure, contrast and gamma
> > settings, which were not changed during the whole acquisition process.
> > Nevertheless, there are slight color differences between some frames which
> > I have been unable to fix/explain, and in general keeping consistent color
> > has been a very difficult task with this mosaic, especially for the
> > brightest areas. Mosaic frame boundaries are also well visible; I know they
> > should be corrected, but really don't have the time.
> >
> > I'll appreciate your comments and advice regarding this image, especially
> > about color.
> >
> > If you definitely hate to see a color lunar image, here is the processed

 > luminance:
 >
 > http://www.astrosurf.com/pleiades-ap/20030409/mosaic-L-atw.3000.jpg
 >
 > Enjoy it.
 >
 > - Juan Conejero.



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