Sharpen-filter using Pillow - The Python Image Processing Library

Overview:

A sharpening filter makes the transition between the various regions present in an image more obvious rather than being smooth.
As an image passes through a sharpening filter the brighter pixels are boosted as relative to its neighbors.

The class ImageFilter.SHARPEN of the Pillow library implements a spatial filter using convolution to sharpen a given image.
An image object is constructed by passing a file name of the Image to the open() method of the Pillow’s Image class.
To get a filter applied onto an image the filter() method is called on the Image object. Only the class name of the filter is passed as the parameter.
In the Python example below, the name of the filter class passed is ImageFilter.SHARPEN, an object of which is created within. ImageFilter.SHARPEN has the convolution matrix for sharpening.

(-2, -2, -2,

-2, 32, -2,

-2, -2, -2)

a 3x3 matrix.

The filter() method applies the convolution matrix to the image pixels and returns the sharpened image.

from PIL import Image
from PIL import ImageFilter

# Open an already existing image
imageObject = Image.open("./MountainsAndOcean.jpg");
imageObject.show();

# Apply sharp filter
sharpened1 = imageObject.filter(ImageFilter.SHARPEN);
sharpened2 = sharpened1.filter(ImageFilter.SHARPEN);

# Show the sharpened images
sharpened1.show();
sharpened2.show();

Before applying sharpening filter using Pillow, The Python Image Processing Library

Sharpen filter applied once on the original image using Pillow-the Python Image Processing Library

The sharpened filter applied twice using pillow