# How to remove gaussian noise?

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Abirami on 1 Nov 2014
Commented: Image Analyst on 28 Dec 2020
Hello, I'm working on image encryption. I need to see how well my encryption is so i thght of adding noise and testing it.I added gaussian noise with the following code.My problem is i dont know how to remove it before applying decryption algorithm.i get decimal values, I want to get whole numbers in the resulting matrix.
I=imread('leena.bmp');
M =0;
V=0.01;
imshow(I);
title('Original Image');
J = imnoise(I,'gaussian',M,V);
gure,imshow(J);
title('Gaussian Noise');
i'm planning to add other noises as well like poisson noise, speckle noise and salt and pepper noise. Is there any possibility that a code exists for removing all these noises separately? please help..thanks in advance
##### 2 CommentsShowHide 1 older comment
Image Analyst on 13 Aug 2020
Did you look up imnoise() in the help? M is the mean and V is the variance. From the help:
J = imnoise(I,'gaussian',m,var_gauss) adds Gaussian white noise with mean m and variance var_gauss.

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### Accepted Answer

Image Analyst on 1 Nov 2014
For Gaussian noise, the maximum likelihood de-noised answer would just be a local mean, which you can do with conv2():
denoisedImage = conv2(double(noisyImage), ones(3)/9, 'same');
If you want to do Salt and Pepper noise, then see my attached demos where I use a modified median filter.
##### 12 CommentsShowHide 11 older comments
agung pratama on 13 Aug 2020
Thanks Image Analyst, have a good day

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### More Answers (1)

lakpa tamang on 15 Dec 2019
Image Analyst.. can you explain how does the denoising works actually.. mathamatically?
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Image Analyst on 28 Dec 2020
How are you trying to run it? Is it open in the editor window? Did you click the green run triangle? Then it will run. I just ran it again to make sure everything works fine, and it does.

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