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View Full Version : Noise, *lots* of noise and my ugly face :).


bjfacca
8th June 2002, 08:35
I have this old home video of me and my girlfriend (not what you're thinking):), it has great sentimental value to me and it's looking horrible, I have never seen so much noise in a recording.
I would really like to improve the image quality but as you can see in the image I attached it's hard/impossible do remove all that noise, I already tried the following VirtualDub filters: 2d cleaner, temporal smoother, denoise, flaxen's VHS filter, dynamic noise reduction, smart smoother, smart smoother high quality, spatial smoother and video de-noise.
I got some improvement in the image with some of them but no significant improvement, I've been testing and tweaking filters for 3 days now and nothing :(
Any ideas on how I could reduce the noise? Can this be a dirty VHS tape (my VCR was just cleaned)?
Below is a sample frame:

Thanks
Bruno

Belgabor
10th June 2002, 08:26
As I dont know what you tried, its hard to give advice. But I'll try.

- First, I dont know of any good filter you didnt mention
- Have you tried multiple passes? Like piping a temporal deniose with a 2d one?
- Have you tried multiple instances of filters? (eg one for chroma denoise and another one for luma?)
- Have you tried AVISynth filters? I dont have any experiences with 'em because at the one instance i tried 'em they gave me worse results while taking more time, but that could be diffrent in your case (i was encoding anime)

- No more ideas for the moment

Cheers
Belgabor

bjfacca
10th June 2002, 08:52
- Have you tried multiple passes? Like piping a temporal deniose with a 2d one?

Yes I've tried multiple passes, I will try some other combinations that I still didn't.


- Have you tried multiple instances of filters? (eg one for chroma denoise and another one for luma?)

I couldn't quite understand the difference between this question and the above one. My english is not very good, sorry.


- Have you tried AVISynth filters? I dont have any experiences with 'em because at the one instance i tried 'em they gave me worse results while taking more time, but that could be diffrent in your case (i was encoding anime)
I still didn't try them, I probably will.

Thanks
Bruno Facca

Didée
10th June 2002, 12:09
It´s hard to decide from only a still snapshot - but indeed, it looks not too easy to get something viewable out of that.

Shot in the dark:
[...]
temporalSmoother(4,2) # from (3,1) up to (5,3) SLOOOOW
SmartSmootherHiQ(diameter[5-13],threshold[20-100],amount[192-254],weighted
[...]

Don´t have the exact SShiQ-syntax handy, here at work ... :(

If something in this manner won´t suffice, I´d suggest something I made many good experiences with while those billions of hours working on image editing:

1. gaussian blur of the source ´til all the noise is gone
2. (Eventually) sharpen again with unsharp mask
3. Calculate the difference between the blurred image and the original
4. Result of Step 3 gives you the *mask* for the further:
5. very strong denoising (spatial or whatever deals best) in the plain areas
6. Less strong, more detail-preserving denoising in the edge areas

This would require the MaskedMix-feature of avisynth to work correctly. I don´t know if this is the fact atm. Also it would be VERY SLOW, but almost anything is worth and done for sentiment ...

Another idea:
- try the latest WarpSharp directly in Virtualdub (not in avisynth). With its parameter *Blur Passes* you might get sort of effect that could be useful in some way.

Good luck anyway!

step 3 (the trick in itself) was missing ...

bjfacca
10th June 2002, 17:54
I see it's time for me to start learning avisinth.
I will sure try that as soon as I get my tapes back in a couple of days and capture it again. I sent them for cleaning, maybe that also helps a lot as they're old tape and are probably dirty.

Thanks Didée, your method sound promising :D

Bruno

Didée
11th June 2002, 08:06
In the hurry of typing, I forgot an additional (and important) step:
- Calculating the difference between blurred and original image gives the desired mask. I will edit the above post immediately.

If I find the time, I will try to set up the complete script for the method ... but **don´t** rely on that, time is a MAJOR issue for me :(

Belgabor
11th June 2002, 16:16
Originally posted by bjfacca

I couldn't quite understand the difference between this question and the above one. My english is not very good, sorry.


You're completely right, I wasnt clear and the diffrece is minimal. ;) What I meant was using two diffrent filters in contrast to using the same filter twice with diffrent settings (what I was reffering to is one of the smoother filters where you can enter diffrent settings for luma and chroma noise)

Cheers
Belgabor

bjfacca
11th June 2002, 18:47
Originally posted by Didée
If I find the time, I will try to set up the complete script for the method ... but **don´t** rely on that, time is a MAJOR issue for me :(
I will try to write the script myself, I don't know much about avisynth but I'm learning. It would be nice if you could write it but if you don't have the time don't worry, sooner or later I will do it right :) Thanks

Originally posted by Belgabor
You're completely right, I wasnt clear and the diffrece is minimal. What I meant was using two diffrent filters in contrast to using the same filter twice with diffrent settings (what I was reffering to is one of the smoother filters where you can enter diffrent settings for luma and chroma noise)
I already tried using 2 different filters, even 3 and 4 :) but I didn't try to enter different settings for luma and chroma, sounds like a good idea. Thanks

bjfacca
24th June 2002, 02:20
I just wanted to thank you all for your replies and tell you that I will post the results as soon as I get my hands on a VCR for re-capturing, mine are both broken and I still didn't have the time to fix it. I'll let you know.

Bruno Facca