Salt and pepper code in matlab

I want to convert from this opencv code to matlab code.

My tried code:

% I generated random salt & pepper noise

dim = size(I);

[m, n] = size(I);

saltpepper_noise=zeros((m, n));

saltpepper_noise=rand(m,n); #creates a uniform random variable from 0 to 1

for i in range(0,m):

for j in range(0,n):

if saltpepper_noise[i,j]<=0.5:

saltpepper_noise[i,j]=0

else:

saltpepper_noise[i,j]=255

[Nathan Bblanc]

Not sure I understand your code fully, is I defined before the code begins?

in any case, a few corrections

• the asignment [m,n]=x is impossible in matlab, you can should define them seperatly:

m=size(I)(1)

n=size(I)(2)

• no need to define saltpepper_noise twice, you can just use the second line

• in a for loop, you use the syntax for i=1:m

in general, i suggest you use matlab's online documentation, it's very helpful and full of examples

Answer 1

[Image Analyst]

If you want to use conditionals and be as close as possible to that code (instead of using the built-in imnoise function), then you can do this:

% Get grayscale image
saltpepper_img = imread('cameraman.tif');
[img.rows, img.cols] = size(saltpepper_img);
% Create noise image.
saltpepper_noise = randi(255, img.rows, img.cols, 'uint8');
subplot(2, 2, 1);
imshow(saltpepper_noise);
title('Original Noise', 'FontSize', 15);

black = saltpepper_noise < 10;
subplot(2, 2, 2);
imshow(black);
title('Black Locations', 'FontSize', 15);

white = saltpepper_noise > 245;
subplot(2, 2, 3);
imshow(white);
title('White Locations', 'FontSize', 15);

% Assign black and white to gray scale image.
saltpepper_img(black) = 0;
saltpepper_img(white) = 255;
subplot(2, 2, 4);
imshow(saltpepper_img);
title('Grayscale image with noise', 'FontSize', 15);

Also see attached demos.

[Rooter Boy]

Sir, thank you very much.

[Image Analyst]

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Answer 2

[Image Analyst]

There is a salt and pepper option for imnoise(). Just use that.

[Rooter Boy]

I want to use with if conditionals.

Mat black = saltpepper_noise < 30;

Mat white = saltpepper_noise > 225;

Mat saltpepper_img = img.clone();

saltpepper_img.setTo(255,white);

saltpepper_img.setTo(0,black);

I don't know how to adapt this for my codes.