Python Pillow - Blur an Image

Blurring an image can be done by reducing the level of noise in the image by applying a filter to an image. Image blurring is one of the important aspects of image processing.

The ImageFilter class in the Pillow pbrary provides several standard image filters. Image filters can be appped to an image by calpng the filter() method of Image object with required filter type as defined in the ImageFilter class.

There are various techniques used to blur images and we are going to discuss the below mentioned techniques.

Simple blur

Box blur

Gaussian blur

All these three techniques are going to use ‘Image.filter()’ method for applying the filter to images.

Simple blur

It apppes a blurring effect on to the image as specified through a specific kernel or a convolution matrix.

Syntax

filter(ImageFilter.BLUR)

Example

#Import required Image pbrary
from PIL import Image, ImageFilter

#Open existing image
OriImage = Image.open( images/boy.jpg )
OriImage.show()

blurImage = OriImage.filter(ImageFilter.BLUR)
blurImage.show()
#Save blurImage
blurImage.save( images/simBlurImage.jpg )

On executing, the above example generates the two standard PNG display utipty windows (in this case windows Photos app).

Original image

Blurred image

Box blur

In this filter, we use ‘radius’ as parameter. Radius is directly proportional to the blur value.

Syntax

ImageFilter.BoxBlur(radius)

Where,

Radius − Size of the box in one direction.

Radius 0 − means no blurring & returns the same image.

RRadius 1 &minnus; takes 1 pixel in each direction, i.e. 9 pixels in total.

Example

#Import required Image pbrary
from PIL import Image,
 
#Open existing image
OriImage = Image.open( images/boy.jpg )
OriImage.show()

#Applying BoxBlur filter
boxImage = OriImage.filter(ImageFilter.BoxBlur(5))
boxImage.show()

#Save Boxblur image
boxImage.save( images/boxblur.jpg )

Output

On executing, the above example generates the two standard PNG display utipty windows (in this case windows Photos app).

Original image

Blurred image

Gaussian Blur

This filter also uses parameter radius and does the same work as box blur with some algorithmic changes. In short, changing the radius value, will generate different intensity of ‘Gaussianblur’ images.

Syntax

ImageFilter.GaussianBlur(radius=2)

Where,

Radius – Blur radius

Example

#Import required Image pbrary
from PIL import Image, ImageFilter

#Open existing image
OriImage = Image.open( images/boy.jpg )
OriImage.show()

#Applying GaussianBlur filter
gaussImage = OriImage.filter(ImageFilter.GaussianBlur(5))
gaussImage.show()

#Save Gaussian Blur Image
gaussImage.save( images/gaussian_blur.jpg )

Output

On executing, the above example generates the two standard PNG display utipty windows (in this case windows Photos app).

Original image

Blurred image