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Filtering for different effects
The use of image processing to achieve pleasing effects in images dates back to
the beginning of digital images, but it has recently been the basis of a number of
interesting applications, the most well-known of which is probably Instagram.
Chapter 10
We are going to use a traditional image in image processing, the screenshot of the
Lenna image, which is shown and can be downloaded from the book's website (or
many other image-processing websites):
im = mh.imread('lenna.jpg', as_grey=True)
Adding salt and pepper noise
We can perform many further manipulations on this result if we want to. For
example, we will now add a bit of salt and pepper noise to the image to simulate
a few scanning artifacts. We generate random arrays of the same width and height
as the original image. Only 1 percent of these values will be true.
salt = np.random.random(lenna.shape) > .975
pepper = np.random.random(lenna.shape) > .975
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