Re: Video techniques

From: Allen Thomson (thomsona@flash.net)
Date: Wed Mar 28 2001 - 08:44:08 PST

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    Mr. Molau has kindly replied to my question concerning automatic detection
    of satellites in video imagery.  Reposted to SeeSat-L with his permission:
    
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    ----- Original Message -----
    From: "Sirko Molau" <molau@informatik.rwth-aachen.de>
    To: "Allen Thomson" <thomsona@flash.net>
    Sent: Wednesday, March 28, 2001 02:58 AM
    Subject: Re: Video observations of artificial satellites?
    
    
     Hello Allen,
    
    AT:  My own interest is in observation and orbit determination of artificial
    AT:  Earth satellites, and it seemed that your techniques might be
    applicable to
    AT:  those tasks.
    
     yes, the detection algorithm is very sensitive to satellites as well, so
     I see plenty of them. However, since these are not the stuff we are
     interested in, I have implemented an efficient "satellite filter":
     Everything that moves slower than 3 deg/s is regarded as a satellite and
     discarded.
    
      It would be easiy for me to deactivate this filter, but then MetRec would
     still have a problem with the long duration of satellites: MetRec saves
     the data/image of a meteor once it disappeared. However, the software
     can keep as most 50 video frames in the internal ring buffer. After that
     time, regardless of whether the meteor is still visible or not, the
     detection is finished and the data is forced to be saved on disc.
     Meteors hardly last as long as 2s, so this is no restriction for them.
    
     Since satellites will usually take longer to cross the field of
     view, however, each of them will cause a number of subsequent detections.
     To avoid that would require some modifications of the software.
    
     A simple workaround might be to reduce the frame rate. This can be done
     without modifications.
    
     Best regards,
     Sirko
    
    > **************************************************************************
    > *  Dipl.-Inform. Sirko Molau                  *                          *
    > *  RWTH Aachen, Lehrstuhl fuer Informatik VI  *              __          *
    > *  Ahornstr. 55, D-52056 Aachen, Germany      *       " 2B v 2B "        *
    > *                                             *                          *
    > *  phone: +49-241-8021615                     *             Shakespeare  *
    > *  fax  : +49-241-8888219                     *                          *
    > *  email: molau@informatik.rwth-aachen.de     *                          *
    > **************************************************************************
    > *  www  : http://www-i6.informatik.rwth-aachen.de/Colleagues/molau       *
    > **************************************************************************
    
    
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