How to add additive noise to an image?

1. How is noise added to an image?
2. How do you add salt and pepper noise to a picture?
3. How do you add additive white Gaussian noise to an image in Matlab?

How is noise added to an image?

Image noise is random variation of brightness or color information in images, and is usually an aspect of electronic noise. It can be produced by the image sensor and circuitry of a scanner or digital camera. Image noise can also originate in film grain and in the unavoidable shot noise of an ideal photon detector.

How do you add salt and pepper noise to a picture?

By randomizing the noise values, the pixels can change to a white, black, or gray value, thus adding the salt and pepper colors. By randomizing which pixels are changed, the noise is scattered throughout the image. The combination of these randomizations creates the "salt and pepper" effect throughout the image.

How do you add additive white Gaussian noise to an image in Matlab?

J = imnoise( I ,'gaussian', m ) adds Gaussian white noise with mean m and variance of 0.01. J = imnoise( I ,'gaussian', m , var_gauss ) adds Gaussian white noise with mean m and variance var_gauss . J = imnoise( I ,'localvar', var_local ) adds zero-mean, Gaussian white noise of local variance var_local .