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matlabimage-processingnoise

Adding Impulse Noise in Image manually

How can salt & pepper noise be added to an image separately depending on the PROBABILITY of salt and pepper. imnoise would take ONE value for the noise density as a whole and that value is the measure for both salt (white dots) and pepper (black dots). I want to know if we have just to add white (salt) and then black (pepper) noise separately with two different probabilities. What equation would have to be used?

Solution 
  • clc;
close all;
originalImage = imread('Cameraman.tif');
[rows cols] = size(originalImage);
totalPixels = int32(rows * cols);
subplot(1, 2, 1);
imshow(originalImage);
percentage = str2double(cell2mat(inputdlg('Enter the percent noise: ', 'Enter answer', 1, {'2'}))) / 100.;
numberOfNoisePixels = int32(percentage * double(rows) * double(cols));
locations = randi(totalPixels, [numberOfNoisePixels, 1]);
noisyImage = originalImage;
noisyImage(locations) = 255;
subplot(1, 2, 2);
imshow(noisyImage, []);

    Source

    https://groups.google.com/forum/#!topic/comp.soft-sys.matlab/YcF2xZwnq1o

    That does Salt Noise, Pepper noise would be 

    noisyImage(locations) = 0;

    instead of 

    noisyImage(locations) = 255;