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(meteorobs) Re: WGN video paper
Hello Pete,
thanks for the fast reply on our WGN paper. Here are some thoughts of
mine.
First of all: Our paper is submitted to WGN, no further changes can be
done my now. However, we intended this article to be a working paper. We
did not claim to tell the ultimate truth about video meteor observation,
but we wanted to give a basis for a discussion about the future of that
type of observation. In that sense I see your reply as the first
contribution to the discussion. I will forward it to the other authors.
Hopefully we will receive more replies from other video observers. Maybe
we will publish an follow-up article in WGN made of the the replies.
> Just read your paper (et al) on video history, status and future. It
> parallels a lot of what I wrote about in my article to WGN over a year ago
> (what, no citation???) .
Ok, maybe I should clarify or citation procedure here.
We tried to add as little literature references as possible to the
article. It would have been no problem to make the list of references
longer than the paper itself, but we wanted to avoid that. So we have
choosen only a minimal list of references.
Your WGN paper has indeed a similar character than ours. However, whereas
you develop the idea of an fully automatic meteor detection system, we
intended to give an overview of the whole bandwidth of possible things you
can do with a video system. AMDES is one way the development could go to,
and I would say we really missed to reference your paper in that section.
However, there is much more possible than video systems that run
completely autonomous.
> I am planning to write another on the algorithmic
> appraoch I am using and the trials and tribulations of trying to run PC's
> in real-time in the next month or two (for WGN). At least I know someone's
> interested out there.
I (and also the others :-) am definitely curious to read more about
your algorithmic approach and the results you have come up with so far. I
think we all agree, that automatic meteor detection is the most important
question in that area. The efficieny of video systems holds and falls with
the availability of such systems.
I definitely would have referenced a paper from you in that section of
our article, if only there would have been one. Ideas and plans are the
one thing, implementations and tests of algorithms the other. :-)
> enhance in your article. The first is you may wish to expand on what other
> video developers are working on and more details on the MOVIE system.
The paper was written by five guys who have long time experiences with
video meteor observation. It does not deal with MOVIE, but with all types
of video systems, those currently in operation and those to be expected
in the future.
> For
> example I know you process your data off-line by passing several times
> through the same tape examining different parts of the field each pass.
> The work I have been doing is trying to accomplish the same thing (meteor
> detection) on a single pass.
Ok, this is a special question which is a little of the topic of our
paper. Let's have a closer look at that:
You are right. Currently we have to run each tape four times to inspect
the whole field of view. However, that is not a restriction of the
algorithm used nor my original intention. It is just my current AT bus
frame grabber card which is too slow to allow more. As soon as I have a
better PC with a PCI frame grabber, the same algorithm will be able to
inspect the tape in a single pass. That is ultimate aim, of course.
> The goal being to avoid storage on tape and
> work directly with the video signal (lower noise, shorter turnaround time).
I don't know whether this really is the goal, this is something to be
dicussed further. I see here two ways: Either all data is digitally stored
on a PC (or similar device) and inspected afterwards, or you let your
meteor detection system run continously during the observation and only
store the frames that possibly contain a meteor.
Solution 2 (I guess that's what you are heading for) has the big
advantage, that the amount of data to be stored is only a fraction of
solution 1. However, I still favour the first method. If the automatic
system fails for any reason, the data is definitely gone. Not so in the
first case...
> With a bank of imagers this may become necessary or you may get buried in
> tapes. What about what the others out there are doing? Is there anyone
> else seriously looking into this?
I completely agree: The number of tapes is a serious problem, as long as
we are in the development stage. I hope that we will have it solved once
automatic meteor detection is available.
Beside you and me I know of Chris Trayner from the UK who is seriously
dealing with the problem. That are the three teams mentioned in the paper.
Maybe also Japanese observers are tackling that problem. However, so
far I heard nothing which could support this supposition.
> Another item is that of the use of video systems should also include just
> basic monitoring of activity levels on a night to night basis. I just read
> the article in this months WGN on the survey of meteor observers. Seems
> there are big gaps in observational periods for the typical observer. I
> know due to work, family, and the need for sleep on occasion, I tend to
> only observe clear weekends (fri, sat) or within a few days of major
> showers. Video systems help fill the gaps when fewer or no observers are
> out on a watch!
This is what we address as the third key project, the determination of
flux densities. Looking at the statitics we know, that even a world-wide
organization like IMO with hundreds of observers submitting reports, the
coverage of certain times away from major meteor showers is quite poor. We
all are human beeings who made meteor observations their hobby and not
their profession. Nobody can live without sleep. :-)
With video systems we are able to monitor the activity every night we
want. However, it would make no sense to report this activity from video
observations in terms of ZHR to compare it with human observers. The
ZHR is a construction that describes at it best what a human observer
sees. From that we later calculate flux densities (i.e. the real number of
particles hitting Earth at a given time and area), which is not so easy
because we have to assume certain things about our ZHR. So it makes much
more sense to derive the flux directly from the video records, whose
detection capabilities are much easier to determine.
This is the place where we would gain most from systems like AMDES.
> By the way I would be reluctant to say that we are throwing data away since
> we cannot process the numerous video detections we have. Instead I would
> pose it as a challenge to find more automated ways to post process the
> detected events! I know it is a hard problem, but lets get people thinking
> about it, someone out there may have an idea. I know I have some thoughts
> on it.
I am happy about every meteor that can be processed more. However, let's
be realistic and say, that we will never (at least not in the next 20
years) be able to analyse *all* meteors recorded with *maximum accuracy*.
We just have to find a healthy compromise between number of analysed
meteors on the one hand and the type of analysis on the other, which
certainly depends on the aims we have. For the determination of flux
densities we do not need to calculate accurate meteoroid orbits,
for example.
> Also I find I have no power issues since my imager and camcorder both
> run off the car battery, which is always close at hand as a portable
> warming hut. In fact I take the imager with me on company travel around
> the country, though getting it through security at airports can cause a
> few minute delay. It fits in a medium sized case and can be carried
> onboard, so it is very portable.
We discussed that sentence in our paper, too.
I left it at it's place, because after all a video system is an
electronic device, which needs electrical power. Whether you get it from a
socket, a power generator or a car battery is another question.
Our method (power generator) is good for expeditions, as long as we are
traveling with cars. However, as soon as we cross the borders we may
encounter problems. Do not forget, that video meteor systems have much in
common with certain military devices. This may play no role within the
States, but is more critical here in Europe.
Pete, thanks again for your valuable comments. It is not a paper that
decides the future of video observation, but the people who get involved
and make the best of it.
Best wishes, Sirko
**************************************************************************
* Sirko Molau * __ *
* Str.246 Nr.16 * " 2B v 2B " *
* D-13086 Berlin * *
* smo@informatik.tu-chemnitzdot de * Shakespeare *
* http://www.tu-chemnitzdot de/~smo * *
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