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Image is Noisy or not ?

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Tahira Batool
Tahira Batool on 17 Nov 2016
Edited: Changoleon on 17 Nov 2016
Hey Everyone ! I'm working on a project which includes to examine either the provided/selected image is noisy or not ?Is the given image is aesthetically acceptable or not.what should be the steps to follow to judge that ?
Any helpful response will be highly appreciated . Thanks in advance

Answers (2)

Changoleon
Changoleon on 17 Nov 2016
Edited: Walter Roberson on 17 Nov 2016
Hi. this question is very qualitative. What kind of noise does your images has?
Let's assume your image has "salt & pepper" noise ( please see the attached image - the attached picture has salt and pepper noise and also some other sources of noise)
In order to judge if an image has salt and pepper noise, you could count the number of pixels in that image which have the intensity values of 0 and 255. And if the numbers is higher than a specific threshold then you could say that your image has salt and pepper noise or not. For instance
a = double(imread('actin_noise.bmp')); %( download the attached image )
b = sum(sum(a==255)); %this counts the number of white pixels (salt noise)
c = sum(sum(a==0)); %this counts the number of black pixels (pepper noise)
threshold = 2000; % this number needs to be determined by you
if b||c > threshold
fprintf ('Your image has Salt & Pepper noise /d')
end
  2 Comments
Changoleon
Changoleon on 17 Nov 2016
Once you click on it, the white page will appear. Then you can right click and click on save as to download the image

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Image Analyst
Image Analyst on 17 Nov 2016
  2 Comments
Image Analyst
Image Analyst on 17 Nov 2016
You can read this paper for a comprehensive overview of noise and filtering methods: https://users.soe.ucsc.edu/~milanfar/publications/journal/ModernTour.pdf
The Image Processing Toolbox also has functions std2(), immse(), and psnr().

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