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Re: High speed Tesla spark photographs



Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Terry,

Cool. If you would like to do RAW, my camera can do that (Nikon format). It will be interesting to see if you have any ghosting with a conventional back silvered mirror. You can get reflections off of both surfaces if this is what you have. If that is a problem, one can get the glass aluminized on the front surface without too much cost.

My comment about multiple stacked images was in the context of stacking the same image to improve contrast and reduce noise.

Let us know when you have pictures :o)))

Gerry R.


Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Gerry,

My old camera does not do the "RAW" format, but it seems to be pretty capable. It does "deep" TIFF. But the JPG format is a pretty tough cookie to beat even if it does tricks ;-)) In testing, even the second rate JPG does as well as the super deep TIFF stuff. JPG is not a light weight by any means ;-)) My camera is old, but the software can do the new tricks manually... Your camera can probably do fine too, but we'll work out the bugs first ;-))) I can easily rework the mount to fit any camera. I will use the ~500K JPG mode since it seems fine and it can store a LOT of pictures "fast". The 9MB/pic mode is as slow and heavy as a cow...

The software has filter tools out the wazzoo and you can fiddle with them easily too. You can define your own functions too if one remembers anything from linear systems class ;-)) It actually has "too many" filters... It can even "de-convert JPG artifacts"...

Multiple images are easy as Peter has here:

http://4hv.org/e107_files/public/1158407769_10_FT15766_hvrotmirrorsparkmany.jpg

I don't even know where to begin deciphering all the info there!!!

The real happy news here is that I did get the mirrors in!!! Weddings and funerals dominate the days right now, but I should get this going real soon here... Fast light gathering ability seems to be the big issue... The "bright stuff" is cool, but the real info is in the "dark stuff"... The light thing in the top right of Peter's pictures is a kitchen window ;-)))

Peter's enhanced picture here is sort of the "shot heard round the world"!!!!!

http://drsstc.com/~piranha/PIRANHA/STREAMER.jpg

There are like "years of study" in just hat single picture!!! The clearest picture I know of for such an event!!

Cheers,

        Terry

At 02:32 PM 9/16/2006, you wrote:
Hi Terry,

As Dan has suggested, I think you want to upload the RAW files into the computer and I think you said you can do that. In this way the computer now has all the original info and nothing is lost. Still use the dark frame to remove the hot pixels. Once you have the contrast and brightness set, running the picture thru a noise filter to remove any random noise will certainly help. You may also want to use a sharpening filter to restore the edge sharpness loss from the first filtering (dont know if this will reconstitute the noise but its worth a try). Given the scene content, you may not need to gamma correct and I dont know what your SW does when converting to JPEG. Important thing is to keep RAW so you can always go back to the original and start processing over again. I would be nice to stack multiple images but as Dan says, the arc wont stay still for this.

Gerry R.

Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Dan,

At 07:46 AM 9/16/2006, you wrote:


Terry,

A "dark" frame will only remove non-random noise such as hot pixels.

That is a big problem in my case. The old CCD sensor has significant hot pixels and the "fixed" noise floor has risen over time. This camera does not have a built in function to remove that. The software fix really cleans up super dark photos well.

To
remove random noise generated by the sensor itself, you basically would need
to take multiple exposures of an identical object (such as stars for
example) and then average those frames to remove random noise.

The software just does a 2nd order low pass function which is surprisingly good at this type of noise. It has a lot of various filters but this one does fine. It does chew up the good image just a little but not bad.

Of course,
our arc is not a constant image, so you cannot do that.

Dan

It should be good enough right now.  I will just have to see what happens.

Cheers,

        Terry