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already registered AVIs

 
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Stefano Sposetti



登録日: 2009.01.22
記事: 4

記事日時: Fri Jan 23, 2009 5:43 am    記事の件名: already registered AVIs 引用付きで返信

Hi,

I have stored several AVIs of the Moon surface in my Hard Disk. I want to detect possible meteoric impacts from these AVIs. Is this possible with UFOCapture? Can UFOCapture detect variations brightness from already registered AVIS?

If not, can I use UFOCapture to capture meteoric impacts on the Moon? Can you give me some hints about the detection settings?

Thankyou,
Stefano
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SonotaCo
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登録日: 2004.08.07
記事: 12653
所在地: 139.67E 35.65N

記事日時: Fri Jan 23, 2009 9:37 am    記事の件名: Re: already registered AVIs 引用付きで返信

Hi Stefano
Welcome to this forum.
We have little experience about Moon observation up to now, though it is very interesting.

About the detection from stored video files on HDD, current UFOCapture does not have that function.
I have tried sometimes, it was possible for some cases.
But because there are too many formats on video files in the world, the compatibility is very complicated.
There are almost one hundred video formats only for .avi suffix (.avi is just a container format).
Many of them use own time domain compression and it makes it difficult to detect changes and restore of the video.
Therefore I gave up to publish the functions for them.
Now, re-detection of stored video can be done only by re-input of the video through the recorder outside of the PC.

About the meteoric impacts on the Moon, I am guessing only.
The area mask of UFOCaptureV2 will help the masking of bright area and its scintillation.
But the mask pattern should be re-built every night because the area changes every day.
Physical optical mask like Sun mask in SOHO would be far superior but it may be very difficult.
Precise tracking of the Moon speed may be necessary for the stability of FOV.
Narrow FOV using long focal length telescope might be better to restrict the FOV only in dark side and increase the sensitivity.
.....

I will welcome to discuss about this Razz .
SonotaCo
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Stefano Sposetti



登録日: 2009.01.22
記事: 4

記事日時: Sat Jan 24, 2009 5:17 am    記事の件名: Re: already registered AVIs 引用付きで返信

Thankyou SonotaCo ,

Most meteors hitting the Moon are only 1 pixel size and shows up only in 1 frame (or half frame). Therefore one must adjust the sensitivity at high levels.
I'm not sure that setting UFOCapture to :
Min(frm)=1 (event only in 1 frame)
Max(sec)=0 (very short events)
EXsize=1 (very small events)
DLratio=101 (1% more signal above the noise level)
will detect 1pixel impacts...

>But the mask pattern should be re-built every night because the area changes every >day.

That's a minor problem.

>Precise tracking of the Moon speed may be necessary for the stability of FOV.

No problem. I use "Nudger" a very good software made by George Varros. It autoguides precisely the Moon.
http://www.gvarros.com/

>Narrow FOV using long focal length telescope might be better to restrict the FOV only >in dark side and increase the sensitivity.
My focal lenght is about 800mm and I image about 2/3 of the earthlit part of the Moon. I can exclude from the field of view the sunlit parts of the Moon.
Some background sky is included in my AVIs.

Stefano
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登録日: 2004.08.07
記事: 12653
所在地: 139.67E 35.65N

記事日時: Sat Jan 24, 2009 9:11 am    記事の件名: Re: already registered AVIs 引用付きで返信

Hi Stefano
Stefano Sposetti wrote:
Most meteors hitting the Moon are only 1 pixel size and shows up only in 1 frame (or half frame).

OK, To detect the 1 pixel event,
Detect size = 1 , this is in Live sheet, and is most important.
(EXsize is the size which force a trigger even its duration is
shorter than Min(frm), but it does have meaning when Min(frm)=1)

To detect the 1 frame event,
Min(frm)=1 , this is enough.
Max(sec)=0 , this means no limits of duration,
if there happens long captures by clouds, helicopters or etc,
you should set this like 10, it will cancel the clip longer than 10 sec.

To detect the faint (1% more signal above the noise level) event,
DLratio=101 (1% more signal above the noise level)
MinDL = 1 (allow detect level down to 1)
MinL-N = 0 (allow detect level down to noise level)
But this may be too sensitive. It depends on the stability of video signal and digitizer.
Tune these parameters to avoid the clips by back ground noise, like below or more.
DLratio=102
MinL-N = 2
you should also set
Detect Level Noise Tracking ON,
ScintillationMask OFF, DarkObjMask OFF, SlowObjMask OFF.

Well, this setting is most sensitive one.
You will have many cosmic ray noises. They will happen almost once in a few minutes.
If you think it is too many, tune MinL-N or Detect size.
I think the size will be a bit larger, if the light came from moon.
If you get appropriate settings, please let me know.

Stefano Sposetti wrote:
I use "Nudger" a very good software made by George Varros.

Oh, thank you for info.

Regards,
SonotaCo
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