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Discussion Board -> Photography -> Chrominance vs Luminance image noise

Chrominance vs Luminance image noise

+purmusic
01/29/15 7:54 AM GMT
Going to build a small resource library of articles, links.. on the subject; "Chrominance vs Luminance image noise" in this discussion thread.

'Cause..

I've noticed some struggling with these issues.

How Chrominance and Luminance image noise is effected/affected by post-processing/editing/software.. is the operative question;

"The relative amount of chroma and luminance noise can vary significantly from one camera model to another. Noise reduction software can be used to selectively reduce both chroma and luminance noise, however complete elimination of luminance noise can result in unnatural or "plasticy" looking images."


Starting off.. and from one of my fav websites;

Digital Camera Image Noise - Concept and Types

Image Noise Examples and Characteristics


Feel free to add to the thread.. I insist.
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.gonedigital
02/01/15 5:24 AM GMT
This is a topic that effects me Les as using a bridge camera noise is always more extensive at higher ISOs. I use "Neat Image Pro" with caution whenever necessary, however I believe the fact that it only deals with JPG format is a disadvantage.

I shall be observing this discussion with interest. (o:
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+purmusic
02/01/15 1:30 PM GMT
Feel free to add in your camera models/manufacturers.. as there is a difference.

On two fronts.. one; as to how 'your' individual camera handles things in-camera.

As well as, the camera model/manufacturer's profiles that some software program developers release, in conjunction with their software/program.. to improve performance.

i.e. Neat Image - Library of noise profiles

"Canon :: Casio :: Contax :: Epson :: Fujifilm :: HP :: Kodak :: Kyocera :: Leica :: Konika-Minolta :: Mamiya :: Nikon :: Olympus :: Panasonic :: Pentax :: Ricoh :: Samsung :: Sanyo :: Sigma :: Sony :: Toshiba

Other brands"


More to come..
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+purmusic
02/01/15 1:47 PM GMT
Well, got me curious, Phil.. it would appear that other file formats are supported:

"Neat Image supports the industry standard image types and file formats

24-bit / 48-bit RGB and 8-bit / 16-bit grayscale images can be processed
(individual channels of Lab and CMYK images can be processed by Neat Image plug-in as well)

TIFF, JPEG and BMP file formats are supported in the standalone Neat Image

Any file format supported by Photoshop (or another used plug-in host) can be used with the Neat Image plug-in (for example, you can open a PSD, JPEG2000, RAW, DNG, etc., image in Photoshop and then directly process it with the Neat Image plug-in)"


Maybe you need to upgrade your version? As I noted on their website, depending on which version you have (i.e. '7x') there is a free upgrade to that of version 7.6:

"October 8, 2014

Neat Image 7.6 plug-in is available"


"Updating from 7.x to 7.6

This update is free for licensed users of the version 7 of Neat Image plug-in for Photoshop (Win).
Please use your v7 license to log on to the corresponding download area"
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.gonedigital
02/01/15 9:37 PM GMT
I stand corrected about Neat Image formats Les, what I should have said it doesn't support PNG, which is my favourite choice.

The camera I'm using is a Sony Cybershot HX200V btw and the image quality is poorer than my previous Panasonic Lumix DMC FZ50, but as I'm bird photographer I need the Cybershots 30x zoom lens.

Years ago a good photographer told me that when processing images work in PNG as there's no deterioration in quality in comparison to JPG.
Please tell me something about about my BMP AND TIFF alternative formats are they as durable as PNG?
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+purmusic
02/01/15 10:38 PM GMT
Worth a read through:

"PNG has been created as a lossless image format, meaning it's supposed to exactly preserve all details of an image, even minuscule ones that are hardly noticeable. Preservation of those tiny details costs a lot in terms of file size.

On the other hand, lossy formats (like JPEG) produce much smaller files, because they don't save unneccessary details.

The good news is that PNG can be used as a lossy format and produce files few times smaller, while remaining perfectly compatible with lossless PNG decoders.
Lossy averaging filter

PNG has an ability to 'guess' pixels based on their top and left neighbors and successful guesses compress to almost nothing."


"PNG8

PNG usually needs 4 bytes per pixel for R, G, B and alpha components. PNG8 removes 3/4 of the data from the file by storing indexes of a color palette instead."

(Source: PNG can be a lossy format )

Bear in mind, that if you do check out the link above.. it is for a software program, extolling on it's virtues of better 'PNG' files.

However.. quoted sections above/explanation(s) were straightforward, concise.. and touched on some salient points.


"Is TIFF really of higher quality than PNG-24?"

"You explicitly mentioned PNG-24 - that has eight bits per channel, whereas a TIFF file can have 16. That would be one reason the quality could be higher, from a RAW conversion especially but also if you are doing a lot of editing.

The PNG standard also supports 16-bits per channel (PNG-48) but I don't know how many applications support that, whereas pretty much anything that can read TIFF is going to be able to read a 16-bit TIFF file.

TIFF can also store layers in it, which is not a quality issue so much as a flexibility thing. PNG is really meant to hold an image, not a layered set (although APNG can hold a set, it's really not for the same purpose).

One additional bit of practical information is that TIFF can store many kinds of Photoshop layers, I have used it for images which had a number of adjustment layers applied. That is not possible with PNG, you would have to flatten the whole image."

(Source: photo.stackexchange.com)
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+purmusic
02/01/15 10:49 PM GMT
Just the facts:

"The file types

TIFF is, in principle, a very flexible format that can be lossless or lossy. The details of the image storage algorithm are included as part of the file. In practice, TIFF is used almost exclusively as a lossless image storage format that uses no compression at all. Most graphics programs that use TIFF do not compression. Consequently, file sizes are quite big. (Sometimes a lossless compression algorithm called LZW is used, but it is not universally supported.)

PNG is also a lossless storage format. However, in contrast with common TIFF usage, it looks for patterns in the image that it can use to compress file size. The compression is exactly reversible, so the image is recovered exactly.

JPG is optimized for photographs and similar continuous tone images that contain many, many colors. It can achieve astounding compression ratios even while maintaining very high image quality. GIF compression is unkind to such images. JPG works by analyzing images and discarding kinds of information that the eye is least likely to notice. It stores information as 24 bit color. Important: the degree of compression of JPG is adjustable. At moderate compression levels of photographic images, it is very difficult for the eye to discern any difference from the original, even at extreme magnification. Compression factors of more than 20 are often quite acceptable. Better graphics programs, such as Paint Shop Pro and Photoshop, allow you to view the image quality and file size as a function of compression level, so that you can conveniently choose the balance between quality and file size."


The kicker, between that of JPG, PNG and TIFF file formats:

"File size comparisons

Below are comparisons of the same image saved in several popular file types.

Tiff, uncompressed ... 901K
Tiff, LZW lossless compression ... 928K
JPG, High quality ... 319K
JPG, medium quality ... 188K
JPG, my usual web quality ... 105K
JPG, low quality / high compression ... 50K
PNG, lossless compression ... 741K


"When should you use each?

TIFF

This is usually the best quality output from a digital camera. Digital cameras often offer around three JPG quality settings plus TIFF. Since JPG always means at least some loss of quality, TIFF means better quality. However, the file size is huge compared to even the best JPG setting, and the advantages may not be noticeable.

A more important use of TIFF is as the working storage format as you edit and manipulate digital images. You do not want to go through several load, edit, save cycles with JPG storage, as the degradation accumulates with each new save. One or two JPG saves at high quality may not be noticeable, but the tenth certainly will be. TIFF is lossless, so there is no degradation associated with saving a TIFF file.

Do NOT use TIFF for web images. They produce big files, and more importantly, most web browsers will not display TIFFs.

JPG

This is the format of choice for nearly all photographs on the web. You can achieve excellent quality even at rather high compression settings. I also use JPG as the ultimate format for all my digital photographs. If I edit a photo, I will use my software's proprietary format until finished, and then save the result as a JPG.

Digital cameras save in a JPG format by default. Switching to TIFF or RAW improves quality in principle, but the difference is difficult to see. Shooting in TIFF has two disadvantages compared to JPG: fewer photos per memory card, and a longer wait between photographs as the image transfers to the card. I rarely shoot in TIFF mode.

Never use JPG for line art. On images such as these with areas of uniform color with sharp edges, JPG does a poor job. These are tasks for which GIF and PNG are well suited.

PNG

PNG is of principal value in two applications:

If you have an image with large areas of exactly uniform color, but contains more than 256 colors, PNG is your choice. Its strategy is similar to that of GIF, but it supports 16 million colors, not just 256.
If you want to display a photograph exactly without loss on the web, PNG is your choice. Later generation web browsers support PNG, and PNG is the only lossless format that web browsers support.

PNG is superior to GIF. It produces smaller files and allows more colors. PNG also supports partial transparency. Partial transparency can be used for many useful purposes, such as fades and antialiasing of text. Unfortunately, Microsoft's Internet Explorer does not properly support PNG transparency, so for now web authors must avoid using transparency in PNG images."


When all is said and done.. you will have to convert to a file format that browsers support. And PNG then becomes your friend here, after editing/post processing, that is.

(Source: Digital Image File Types Explained)
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.gonedigital
02/03/15 2:00 AM GMT
You surely know the pros and cons of the image formats Les, it's interesting what you said about "Internet Explorer" I use "Mozilla" myself. From now on when filtering noisy images I'll convert them to TIFF before loading them onto "Neat Image"
One last question to such a well informed techie on PNG, with "PhotoFiltre" when saving an image to file it gives the option of "Interlaced" and then gives these 6 choices:

None
Sub
Up
Average
Paeth
Automatic

I don't understand what they mean and leave "Interlaced" unticked and select "Automatic" FSViewer offers less choice but allows 0-10 levels of compression. It would be good to understand these options. I realise I've directed you off course a bit and promise to ask no more questions about file formats. Lol
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+purmusic
02/03/15 6:11 AM GMT
The Difference Between Interlaced and Non-Interlaced Images

When to interlace an image?


T(oo)L(ong);D(idn't)R(ead).. Or.. N(ot)E(nough)T(ime);D(idn't)L(ook)

From the website's perspective.. an interlaced image will start to display for the viewer as it is being loaded. A non-interlaced image will not display till fully loaded.

So.. from the user's/member's perspective.. don't worry about it. No need to use the option/functionality.


(An aside.. @gonedigitial: Sony Cyber-shot DSC-HX200V Review

From the dpreview.com review of your camera linked above.. going above 800 ISO is problematic, in terms of image quality/noise.)
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.Tootles
02/14/15 3:24 PM GMT
Nice, somewhat confusing thread. :-) Here's a link I came across that might be useful:

How to Avoid Noise in Your Digital Photography
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.gonedigital
03/15/15 11:35 PM GMT
To give you some relevant feedback Les I've started using Faststone Image Viewers noise reduction option with PNG files. At the moment I'm getting good results with only the luminance dial being used. Neat Image was still a disappointment when using converted TIFF files.

Perhaps someone will recommend a good stand alone noise reduction programme? in the meantime I may look at some web reviews.
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