Noise removal by (heuristic?) pattern detection

[vidiot]

...another silly idea...(This could be a topic for the capture thread...(?))
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"Subtract(clip2,clip1) is your friend..." (DG/neuron2)


As i thought about that more ´n more i began to think about noise
removal in higher priced digital cameras (still).

Those make a "dark-shot" to remove noise which is introduced
by some misfunctions in the cmos sensors.
So, if you have "typical patterns" life is easy...
(Just make a mask, do what you need - and your done)

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Now on to video:


Goal:
Remove noise patterns out of captured videos (maybe even out of DVD´s ect.)

How?:
I made an test clip for DVD (in my case just a picture of a "Siemens Stern" (not really))
and capture that after with my WinTV via S-vhs cable from my DVD-Player.

Then I use Subtract to see the noise...
To be honest: I would have make a clip available, but I ´ve problems because clip1 and clip 2 don´t cover each other perfectly and there are also some AR problems showing up (da$n WintV).

Question:
Is it possible to detect heuristic patterns in a short clip and then choosing the right noise removal filter, (maybe generating masks) for the hole clip?

If so the next step would be to smooth a piece of video with your personel "perfect settings", then compare the clip before filtering and after like mentioned and generate for those kind of noise automatic mask filtering.

If I´m totally wrong or you (moderators) think that belong to capture forums,
feel free to move or delete that one...

Harald

[WarpEnterprises]

A problem would be how to obtain the "reference" clip.
In your example it's easy, but normally you have only one clip.

The only way I can think of is detecting regular(periodic) patterns (flicker in the time-direction, single-frequency-noise in X/Y).
The thing that WaveletNoiseReduction does maybe worth for further research, as there are many "noises" with regular patterns (flicker, macroblocks, moire, interferences,...)

[droolian01]

Hi there.

This topic seems to have been discussed previously here:-

http://forum.doom9.org/showthread.php?threadid=28438&highlight=average+noise (http://)

It's been ages since i read it, can't remember if its totally relevent, and am at work now so can't really concentrate.

Hope this is useful

[vidiot]

@droolian01:
Yes, I know that one.
But I don´t want to capture full movies twice.:D
Thankyou anyway.

And @WarpEnterprises:
You´re absolutley right about the pattern thing (and heuristic is obviously the wrong word!, thx).

To get the second clip if the source is a bad DVD for example:
Took the source clip as "clip1"
and your filtered one as "clip2"

The filter should seek for repeating noise patterns and "suggest"
the best solution for it, regardless if it leads to a "mask" or to
your prefered WNR.

kind regards
Harald