Help with noise removal - DPChallenge Forums

Nikon AF-S VR Zoom-Nikkor 200-400mm f/4.0G IF-ED

12/13/2004 04:34:57 PM · #1

Now, I know in the past I haven't exactly been what you'd call a 'fan' of Neat Image, however, I'm presented with a problem that I believe requires it. Unless there's something else that'd do the trick .. maybe something in PS using layers? Just a suggestion.

I have important family photos that are noisy from using a high ISO setting. When converted to B&W that noise just POPS out.

How to salvage them? It's pretty important that they look good at an 8x10.

Thanks all! I know I can count on your expertise :-)

spydr

Nikon D850

12/13/2004 04:39:39 PM · #2

If you have PS, convert the image to Lab mode. Apply a generous gaussian blur to the "a" channel then to the "b" channel. Convert back to RGB. If needed increase size in 10% increments.

moodville

Nikon D100

12/13/2004 04:43:40 PM · #3

If it increases in noise when you convert to black and white then it is likely the blue channel. Look through the channels in PS to find out which is the problem channel and you can probably discard it. If you want to go the neatimage way then it's normally best to purchase it and apply it to a layer in PS and you can change the opacity of the layer to reduce the effect. There are also some other noise reducing products out there and PS actions that claim to help too.

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

12/13/2004 04:46:04 PM · #4

Originally posted by moodville:

I've recently made a couple of Grayscale images using only the Green Channel, and discarding both the Red and Blue Channels, then applying a Curve to final tonal adjustment.

12/13/2004 04:46:29 PM · #5

If they are to be b/w maybe try working with the red channel as much as possible (don't take my word for that. Split the channels and see which is cleaner). It should be less noisy. Do you have virtual photographer? Pop em in there and give it a spin. Should create at least one that you will be happy with. And then there is noiseware, free and works, to me, somewhat better than ni.
If all else fails, add noise and tell them it's the "current" most requested process.

12/13/2004 04:46:35 PM · #6

Anything I don't have to buy would be optimal :-) if I have to use NI there might be a free trial download somewhere. Yes? No?

My PC is in the shop right now, but I wanted to be armed with noise-reducing techniques for when I get it back.

Thanks :-)

Sony 16-50mm f/3.5-5.6 E-mount

12/13/2004 04:47:40 PM · #7

Originally posted by pcody:

If all else fails, add noise and tell them it's the "current" most requested process.

I half considered that already ;-)

jmsetzler

Sony Alpha a6000

12/13/2004 04:47:57 PM · #8

I have found that playing around with the color layers, as mentioned here, is quite useful. In a b/w image, I have found noise in different channels and I often use the dust/scratches filter to remove a lot of it. There is a lot of experimentation left for me to do in this area, but the individual channels are a great place to start.

12/13/2004 04:49:10 PM · #9

Would you want to post one for everyone to work with? I could host it here if you want.

12/13/2004 04:52:13 PM · #10

dang it! I keep hitting "quote" instead of "edit" and duplicating my posts...

Message edited by author 2004-12-13 16:53:39.

12/13/2004 04:53:10 PM · #11

Originally posted by GoldBerry:

Originally posted by pcody:
Would you want to post one for everyone to work with? I could host it here if you want.

I'd have no problems with that except they're all on my pc which is in the shop till later this week. When I get it back I'll try and get one up! (my internet @ home was busted, too).

P.S. did I mention I've got about 20 noisy images that ALL need to be cleaned up? Volunteers?? Yes?? No?? lol

12/13/2004 04:57:10 PM · #12

I'll send you my email. Send one when you get a chance. I should have room left for a larger one if it's just temp. Then when everyone has a go at it, maybe the "winner" would be willing to help you out more.

12/13/2004 05:04:53 PM · #13

Originally posted by pcody:

K, thanks! I'm hoping that with the tips already given I should be able to whip something decent up. I'm not totally PS handicapped, just never had noise issues before now!

scottwilson

Canon EOS-350D Rebel XT

Canon EF 28mm f/2.8

12/13/2004 05:22:33 PM · #14

You said you would be printing this out as 8 by 10s. If you have not already printed one out you might be surprised at how much noise a photo can have in it and still look good printed. This is why film works at all BTW.

When we look at the photo on the computer screen we see all the noise, but when it is printed out the noise tends to be so small in â��grainâ�� that you donâ��t notice it that much.

The danger is that you might well try to get rid of most of the noise and lose much of the detail in the photo. If you do use a noise reduction program go very easy with it, people tend to go way overboard. Make printouts as you go to see how it will look printed.
.

dazzler

Canon PowerShot A40

12/13/2004 05:27:13 PM · #15

Isnt it just that you dont like Neatimage because you feel you can do it manually just as well? ;)
I am happy with Neatimage, it helps me a lot with noisy pictures.

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

12/13/2004 05:31:30 PM · #16

Does NeatImage and/or similar programs work on Grayscale, LAB, or other color spaces? On individual channels?

jenesis

Canon EOS-300D Rebel

Canon EF 50mm f/1.8 II

12/13/2004 05:32:30 PM · #17

Originally posted by GoldBerry:

Last I checked, you could download a free version of neatimage. It's more limited than the "paid" version but it doesn't put a limit on how many times you can use it like some demo versions do. Neatimage website

Azrifel

Fujifilm X100VI

12/13/2004 05:36:20 PM · #18

Originally posted by pcody:

If they are to be b/w maybe try working with the red channel as much as possible (don't take my word for that. Split the channels and see which is cleaner). It should be less noisy.

Theoretically it should be the green channel that is the cleanest.
The reason for this is that most sensors (excluding your wonderful SD9 sensor) have the following 'Bayer' layout (each letter is a single-channel photodiode/pixel; R=Red etc):

RGRGRGRG
GBGBGBGB
RGRGRGRG
GBGBGNGB

Note that in this 4x8 layout there are 32 'pixels'
16 Green, 8 Red and 8 Blue.

There is twice as much green as there is red or blue. So the green channel gets the most true light and the least Bayer-interpolation (to make each R, G, or B a full R+G+B channeled pixel). Therefore it should be the least noisiest. The blue channel is the noisiest, there are some special reasons for that.

12/13/2004 05:36:51 PM · #19

Thanks all :-)

My beef with NI is it's complete overuse on any one image.

The idea of printing first to get a feel for the shots is a great suggestion. Will do!

scottwilson

Canon EOS-350D Rebel XT

Canon EF 28mm f/2.8

12/13/2004 05:55:58 PM · #20

Originally posted by Azrifel:

Originally posted by pcody:
If they are to be b/w maybe try working with the red channel as much as possible (don't take my word for that. Split the channels and see which is cleaner). It should be less noisy.

Theoretically it should be the green channel that is the cleanest.
The reason for this is that most sensors (excluding your wonderful SD9 sensor) have the following 'Bayer' layout (each letter is a single-channel photodiode/pixel; R=Red etc):
There are a number of reasons that the red chanel

RGRGRGRG
GBGBGBGB
RGRGRGRG
GBGBGNGB

Note that in this 4x8 layout there are 32 'pixels'
16 Green, 8 Red and 8 Blue.

There is twice as much green as there is red or blue. So the green channel gets the most true light and the least Bayer-interpolation (to make each R, G, or B a full R+G+B channeled pixel). Therefore it should be the least noisiest. The blue channel is the noisiest, there are some special reasons for that.

There are a number of reasons that the red channel might have the least noise. One is that peoples skin tends to show much less blemishes in red. The more important reason deals with the light you shot the photos in, if it was incandescent lighting then there is much more red in the light then green or blue. In this case the gain for the green and blue pixels has to be turned up, and thus more noise.

12/13/2004 05:58:48 PM · #21

When I go into PS and split an image into RGB, how does it look and how do I handle the layers? I use layers quite a bit but have no experience in splitting color layers. Do I merge the layers again after?

Message edited by author 2004-12-13 17:59:32.

12/13/2004 06:15:46 PM · #22

The sigma does not have a bayer pattern. That's why it's so great. It has each color layered over each pixel. So where most digital cameras have 2 green,1 blue,1 red(or whatever pattern) totaling 4 pixels the sigma has 4 blue,4 green and 4 reds. Pretty nifty.
edit: but let's not get into that can of worms because, as anyone knows, in each situation, only four pixels can be used at any one time. You just get the pure pixel per pixel color with a sigma.
edit again: have to learn the definition of "excluding". Sorry.

Message edited by author 2004-12-13 18:22:40.

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

12/13/2004 06:19:19 PM · #23

Originally posted by GoldBerry:

Look at Channels, not Layers. It's usually another tab in the same palette.

12/13/2004 06:23:28 PM · #24

Originally posted by GeneralE:

Look at Channels, not Layers. It's usually another tab in the same palette. [/quote]

sorry, that's what I meant..I've never worked on the separate channels before.