There are several ways that noise can be introduced into an image, depending on how the image is created. Noise can also be the result of damage to the film, or be introduced by the scanner itself. Electronic transmission of image data can introduce noise. The toolbox provides a number of different ways to remove or reduce noise in an image.
Different methods are better for different kinds of noise.
The examples in this section use this function. You can use linear filtering to remove certain types of noise. Certain filters, such as averaging or Gaussian filters, are appropriate for this purpose. For example, an averaging filter is useful for removing grain noise from a photograph. Because each pixel gets set to the average of the pixels in its neighborhood, local variations caused by grain are reduced.