Digital Camera - Image Noise Filter Tutorial - One Method

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DJJohnson
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Posts: 29
Joined: Sat 30 Sep 2006 08:12

Digital Camera - Image Noise Filter Tutorial - One Method

Post by DJJohnson » Sat 28 Oct 2006 19:48

I remember reading a tutorial for a noise-remover in the past that gave some simple methods to use their software. Its options were very similar to the ones in PhotoLine. By setting that filter's blend level and other adjustments to maximum settings when starting out you would then work the process in reverse. Obliterating all noise and detail and then lowering settings to bring back only the detail you want. After that was done then you just moved the blend level back from 100% until you found a happy balance with the least amount of noise and reclaiming the most detail. With the lack of detailed English explanations in PL32's help for their "Image Noise" filter I thought I'd see if I couldn't find the same work-flow to their adjustment options.

Here's what I found that seems to work in most instances with PL32 when using this "reverse noise removal" method:

1. Put all your "Image Noise" settings to 0.00 and set all the check boxes to "Activ" (Active).

2. Select an area of your image in the preview window with good edge detail subjects next to some highly visible noise in smooth regions. Resize the window larger if you need to to view both kinds of image data at the same time. But beware that the larger the preview window the more work the filter has to do and it slows it down. An example area to preview would be empty sky next to thin tree branches. Zoom in on your image so the noise becomes very obvious, but keep the area with detailed subject matter still in view.

3. Put all the sliders to maximum except for "Sharpen", leave that at 0.00 for now. And put the "Limit" slider to about 6-10%. 8% works well if you are unsure.

4. Adjust the "Color Noise" slider to the left (lower values) until all the main color areas of your image now define the detailed areas in your image. Move the preview around to check other areas of your image to make sure you have reclaimed all the color for your subjects and fine-tune this slider if needed. When satisfied return to your original noise+detail preview area.

5. Move the "Size" slider to the left (lower values) until you get some finer detail back, but all your noise still remains invisible.

6. Move the "Limit" slider to slowly decrease the value until the detail that you want to retain comes back even more while still keeping out your unwanted noise.

7. Move the "Intensity" slider to the left to lower the value from 100 until you are pleased with how much detail shows up, while still trying to keep out any noise that you can't live with.

8. Increase the "Sharpen" slider to the right until you get some sharper edges. Watch for any overly obvious signs of distracting halos on high-contrast edges. The same way you use any unsharp-mask. Don't over-do sharpening. What may look just right to you will probably look over-worked to another's more discerning eye.


This method of working this type of noise-filter backwards (getting the detail back, instead of trying to remove noise from detail) seems to help me understand what each adjustment is doing, as well as being an easy method for most subjects. Once you have done noise removal this way a few times you can find your own best way to use it. I'm so familiar with noise removers like "NeatImage Pro" and "Noise Ninja", among others, where you select sample-regions of noise that I find it a little more difficult to effectively use some of the one-slider-does-all noise removers.

You may have similar success as these other more dedicated noise remover programs by using PL32's "Image Noise" filter in 2 or 3 passes, using a copy of the image in a layer for each pass. But you'll have to remember to only apply the sharpening on your last pass/layer, as well as become very familiar with what each slider adjustment is doing. The method outlined above is a good way to see and learn what they do. For me at least.

If someone has a better explanation and method of how to use and learn PL32's Noise Filter settings, please share. There are many ways to get from A to B, this is just one of them.

knipser
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Joined: Mon 24 Apr 2006 18:46

Thanks for the instructions

Post by knipser » Sun 29 Oct 2006 22:06

Thanks for the instructions!

What is your impression about the results you can achieve with the PhotoLine denoise tool?

DJJohnson
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Posts: 29
Joined: Sat 30 Sep 2006 08:12

Post by DJJohnson » Mon 30 Oct 2006 02:42

While I don't think you can get as good as results as some of the more dedicated programs designed just for this task (two of them mentioned already), I think with some practice and learning how to use the adjustments properly you can get some very nice results. I'm so used to removing noise by size (small, medium, large) in the other programs that I don't know how well the one in PL32 will compare to that. It having only the one-pass for a one size seek-and-destroy mission. My mind has always been geared to the kinds of programs where you can select a sample of the noise and then have the de-noiser try to subtract that from the rest of the data. I suppose this could be a brain-block from the years in audio-editing where that method is almost always used. Sample Noise / Subtract Noise.

It would be interesting to have this filter compared to others in more capable hands. From the little that I've played with it so far it seems to do a quite admirable job compared to other one-pass filters that I've used. You just have to practice with it, something that I still need to do also. It's not very intuitive on how to use it but that doesn't mean it's not an excellent noise-filter. If you've never seen a piano before and were asked to play it you might be in the same boat. If you couldn't play it it doesn't mean that the piano couldn't be used for a concert performance, it only means you'd need to practice. :-)

I'm finding much in PL32 like that. "Here's the tools, they'll do most anything that you need and do it very well, now learn to do it!" :-)

(Shameless confession time: I keep my Noise Ninja plug-in installed in my common-files plugin folder. So I tend to reach for that first, out of habit and familiarity. I thought I'd give the filter in PL32 a good work-out the other evening just to come up with a half-way decent tutorial that might help others. Its settings confused me, I figured it would confuse other English-only first-time users too.)