( 1)J = imnoise(I，type)；
(2)J = imnoise(I, type, parameter);
Where I is the gray matrix of the original image, and J is the gray matrix of the noisy image;
Generally, (1) is enough, (2) indicates that parameters are allowed to be modified, and (1) uses the default parameters;
There are five types, namely "Gaussian white noise", "local variable" (zero mean Gaussian white noise related to image gray value), "Poisson" (Poisson noise) and "salt &; Pepper' (salt and pepper noise) and' speckle' (speckle noise); Specifically, (2) parameter values can be set according to individual needs; For the rest of the information, if you still don't understand, please refer to the Matlab help file.
Use' salt &; Pepper' (salt and pepper noise), and set its parameter to 0.6. Examples are as follows:
l = im read(' image _ ori . jpg ')；
J = imnoise(L,' salt & pepper', 0.6);
imshow(J)； //A window pops up immediately to display the image with noise added.
imwrite(J，' image_noise.jpg '，' jpg '，' Quality '， 100)； //Store the noise image with the quality of 100%, and the default quality value is 75.
The above program is to add salt and pepper noise to the original image, but pay attention to put the image and the M file of the above program in the same subdirectory.