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Open Source Image De-Noising
GREYCstoration is an open-source tool able to de-noise, inpaint, or resize 2D color images. This is a command-line program developed by the IMAGE team of the GREYC Lab in France and is available for Unix, Mac, and Windows systems under the CeCILL license. The algorithm is based on anisotropic diffusion partial differential equations. These equations are able to smooth an image while preserving its main structures. The demo page presents interesting examples of color image de-noising and reconstruction. This is a serious free alternative to commercial products like Noise Ninja or Neat Image that perform the same kinds of operations. The tool is still a little bit hard to use (command-line based), but I hope the simple C++ API will ease the integration of the algorithm in more user-friendly interfaces. Previous versions of GREYCstoration are already available in Digikam and Krita.
Can it remove the noise commonly used in CAPTCHA images? Will this be the next weapon in the war against spammers?
Another great free tool is called Picture Cooler. It rivals or exceeds Noise Ninja for certain images. Download it here: http://denoiser.shorturl.com/
. size.matter/
But if you want images with less noise, try and buy a camera with a larger sensor. dSLR's have large sensors as do many Fuji cameras including their tiny P&S models. Most sensors on subcompact P&S cameras measure only 5.76x4.29mm (1/2.5"). Many of the smaller cameras by Fuji use a 1/1.8" sensor that measures 7.18x5.32mm.
A nice explanation of noise and sensor size is here: http://www.clarkvision.com/imagedetail/does.pixel
It seems to perform a lot better when dealing with artificially-added noises than real-life images, as if it already knows how to tackle them.
This pyramid photo has basically been 'ruined' after the denoising, I wonder if we added some synthetic noises in the background while leaving the stone face as is, would this app be able to denoise correctly?
Virtual Betting on Facebook for non-geeks.
This tool looks very cool, but today's semi-pro and pro (and even some consumer grade) cameras will store their images in a raw format which preserves 12 bits per color channel at a minimum.
GIMP can't deal with these. Tools such as ufraw can convert them to 8 bits/channel images such as JPEG but don't allow you to actually manipulate the image in its native color resolution.
Linux seriously needs a good image manipulation tool such as the GIMP with 16-bit or even 32-bit per color channel support built-in. This is particularly important for operations like sharpening.
Cinepaint will do it but it's way behind in features compared with GIMP these days.
What's the hold up with GIMP anyway? You'd think its developers would take this kind of issue seriously and would fix the engine to natively do, say, 32 bits per color channel internally.
Use 'slashdot stuff' in the subject line in any email you send me if you want to get past the spam filter.
is a pretty good algorithm. We use it for MRI images. The biggest problem is setting the parameters. Fortunately it's an embarrassingly parallel algorithm so I wrote a version that will run realtime on a video card. It's pretty cool to move the slider and watch the noise fade away, move it further and some of the edges blur, further and you start to lose the image.
"The demo images are more than a little impressive."
I disagree. They are overly smoothed and detail is destroyed. They look like the type of thing a noob makes upon discovering video filters. For example, look at the delicate features in the jellyfish or the pig's hair. This samples look more like demonstrations of soften or posterization filters. They should also use real, not artificial, noise.
by taking off my glasses!!
The lower ISO you can get the more detail you could capture given that other parameters are fixed. Have you ever shot with Velvia ISO 50 film? -- it creates stunning details. I think Fujifilm discontinued it last year or so. In film the lower the ISO the finer the grain. As far as digital is concerned think of ISO as sensitivity of the CCD. You can turn the gain up to ISO 3200 but you will amplify a lot of noise too.
... after those results, I don't want to hear any more bitching about reading yellow license plate numbers off of the reflection of a doorknob reflected in a one-pixel wide eyeball in a black and white security film shown in CSI!
I keep pressing my ear to my computer, but the pictures don't make any noise. They're actually pretty quiet.
Leave the gun, take the cannoli -- Clemenza, The Godfather
It can also take one image and repaint it in the style of another image, so you can take a black and white photo and a pencil sketch as inputs and end up with your photo rendered using parts of the pencil image which are similar in form.
Another trick it can pull is creating tileable textures from any image. Sometimes the results are a little surprising if you start off with a picture of people at a party but they are totally seamless.
It comes as a GIMP plugin and is easy to use if you are used to the GIMP.
Anything I post is strictly my own thoughts and doesn't necessarily have anything to do with the opinions of IBM.
TFS: "GREYCstoration is an open-source tool"
"A witty saying proves nothing." - Voltaire
If you're experiencing a lot of noise at ISO400, it's time for a new camera.
Also, in response to your later post, what many DSLRs do for long exposures (usually taken at night and with high ISO and experience a lot of noise in the black areas) is to take another exposure immediately after the first one, but with the shutter closed. Then, the camera knows where the sensor noise is and can subtract it from the actual picture.
So if you take an 8 sec. exposure and your camera freezes up for the following 8 sec, you'll know why.
"Avoid employing unlucky people - throw half of the pile of CVs in the bin without reading them." -- David Brent
In fact, there already exists software for that purpose: ALE. And it is open-source too!
They should also use real, not artificial, noise.
Check out very impressive clean up of a PDA camera. That's good. Ordinary smoothing filters blur important details, like those in the watch or the baby's ear. How nice that it is already in Digikam, one of the easiest to use photo managers out there.
Friends don't help friends install M$ junk.
Sure, he's a noob. That DT-MRI of gray matter paths in your brain based on diffusion tensors is purely the stuff of rank amateurs!
Being a research scientist doesn't necessarily qualify someone as having a photographer's eye. Nobody's saying the guy couldn't research circles around any of us. What the parent poster said is his de-noise filter is way too aggressive and obscures image detail. That appears to be true, at least judging by the settings he's using for his demo shots.
Sufficiently advanced noise is indistinguishable from the stuff that comes out of a cheap imaging device
Not really true, because the noise that comes out of any imaging device (cheap or otherwise) is not random. It fits a particular profile that's unique to that model of device, or even that particular unit. Advanced photo filtering algorithms (including those used in the in-camera processors that convert raw image data to jpg image files) use that individual profile to filter noise. They're not trying to figure out what's noise and what isn't on the fly, which is at best an imperfect science, and that's being charitable. They have a good idea before they even look at an image what the noise is going to look like, so they do a better job of removing it without sacrificing detail.
The more advanced filters like NeatImage are also almost infinitely configurable in what noise they go after and where, and how aggressive they are. Now, this guy's algorithm seems to be pretty configurable as well, so maybe he just didn't use very good settings himself on most of his image demos, and the algorithm is actually capable of better results. He does seem like he's a better scientist than image-maker so that's entirely possible.
It would be interesting to see what could be done with this if it was given an intuitive GUI and put in the hands of some real photographers. (Yes, even real photographers have to shoot at ISO 800 and above occasionally, and would benefit from noise reduction that actually works without sacrificing detail.)
I too have a fridge full of film (Velvia, Astia, Provia), however I accept that I'm a dinosaur and proud of it! Modern digital SLRs perform better than 35mm film in practically every respect and challenge medium format in quality. Only with large format is that not true - and large format is something of a niche! Soon of course even this will bow to the digital revolution.
I suspect she's like me, stuck in the past and quite happy to stay there for the time being! There's still something magical about transparency film. The colour reproduction is very special, with a gamut wider than you can sense in either prints or monitors. Although the gamut of modern digital sensors is just as good, there's no way of actually sensing it, as the display devices aren't up to snuff! Wide gamuts make an enormous difference to an image. The colors you see in nature are far more diverse than those that can be reproduced in print or on a computer screen. It's only by actually seeing these things first hand that one can appreciate the difference, prints look strangely grey an lifeless in comparison.
Ah, transparency film!
I'll stop evangelising now - I'm probably preaching to the converted anyway!
Be nice to people on the way up. You will meet them again on your way down!