Non-Local Means Filter

Non-Local Means Filter for image denoising

Description

Implementation of the Non-Local Means Filter proposed by Buades et al. for robust image denoising.

typical usage:

fima=nlmeans(ima,5,2,sigma);

being sigma the noise standard deviation

• MATLAB release: MATLAB 7.0.1 (R14SP1)

[selma]

thanks for helping us

[Prabhakar]

Suggest me how to give external image by applying this code

[sadaiyandi]

max(a,b)
what is the return type its array or int value i am getting trouble when i am implementing in java

[Zhang Xuande]

cool!!

[YoonOh Tak]

Is this line right?

fima=NLmeansfilter(ima,5,2,sigma);

I think it has to change like below

fima=NLmeansfilter(rima,5,2,sigma);

[priyanka reddy]

i have the same doubt what crisitna asked. can you help me. can u send me the modified codings

[Royi Avital]

Hello.
You mention to have the "Original" version which is slower yet easier to understand,
Where can I find it?
Thanks.

[Tai Fei]

Hi, Jose, I have 2 questions on the kernel.
1). Is it gaussian kernel which is mentioned in the paper of Buades. As far as i know, the one in your code is not gaussian.
2). why you take these two steps ?
average = average + wmax*input2(i1,j1);
sweight = sweight + wmax;

I cannot find any ground in the original paper, but it does make my algorithm oscillate less. could you give me some idea, why you make them ?

[Victor Lee]

Hi Jose, you've mention of the bug earlier on but I can't seem to find it. Is it rectified and updated?

[Abhishek Bansal]

how to calculate sigma, h and f? I am confused. I am a student, need urgent help. u can also email me at [e-mail]

[Haoheng Zheng]

Good, but few notation...

[Vijay]

Performance of the algorithm will depend on the sigma estimation in noisy image. How to estimate good sigma?

[cristina]

I must define input,f,t,h...I'm not sure that I know how!
Can you help me please?I'm a beginer in matlab...thank you!

[cristina]

I have a little error here [m n]=size(input); in NLmeansfilter.m:

> NLmeansfilter
??? Input argument 'input' is undefined.

Error in ==> C:\Documents and Settings\Iulia\Desktop\matlab\NLmeansfilter.m
On line 19 ==> [m n]=size(input);

I need help...Thanks!

[Jose Manjon]

You are right Bi Yiming.

Sorry about that.

Jose

[Bi Yiming]

i think it should be
fima=NLmeansfilter(rima,5,2,sigma);
not fima=NLmeansfilter(ima,5,2,sigma);
in demo.m

[Kevin Verghese]

d = sum(sum(kernel.*(W1-W2).*(W1-W2)));
This line throws an error.
"Error using ==> times
Integers can only be combined with integers of the same class, or scalar doubles."
How do we rectify that?

[Jose Manjon]

You have to use sigma, not 10*sigma

being signa the image noise standard deviation

Jose

[Roger Ting]

How to set the sigma for the algorithm.I chose 10*noisesigma, the result is very bad.

[Reza Farrahi Moghaddam]

Good Work,

Only, please change the word "radio" to "size" (in the definitions of "t" and "f")

Thanks

[victor diaz]

 

[Jose Manjon]

The original code was not optimized to easily understand the filter caracteristics. Now, I have already vectorized it to speed up the filter. New version is much faster but if you plan to use it rutinarily I suggest you to mex it.

[Peter L]

It is really slow. You need to vectorize it.

[Jose Manjon]

There is a small bug in the code, please
chage:

k=max(abs(i),abs(j));

for

k=max([abs(i),abs(j),1]);

enjoy the filter

Jose Manjon

[James Chan]

cool