When it comes to processing images, there are a couple of ways to smooth sharp edges, remove the noise from an image and find the edges too. Physics AS requires you to know how to image process a given image and understand why people process images. I will go over the main types of image processing here: mean, median and finding the edges using the Laplace rule.
The mean is used to smooth sharp edges and soften the image.
Rule - Replace each pixel by the mean of its value and those of it's neighbours.