Wand unsharp_mask() function – Python

Last Updated : 08 May, 2020

unsharp_mask() is similar to normal sharpen() method in python Wand, but it gives control toblend between filter and original(amount parameter), and the threshold. When the amount value is greater than 1.0 more if the sharpen filter is applied, and less if the value is under 1.0. Values for threshold over 0.0 reduce the sharpens.

Syntax :
wand.image.unsharp_mask(radius, sigma, amount, threshold)
Parameters :
Parameter Input Type Description
radius numbers.Real Size of gaussian aperture.
sigma numbers.Real the standard deviation of the Gaussian, in pixels.
amount numbers.Real The percentage of the difference between the original and the blur image that is added back into the original
threshold numbers.Real The threshold in pixels needed to apply the diffence amount.

Parameter	Input Type	Description
radius	numbers.Real	Size of gaussian aperture.
sigma	numbers.Real	the standard deviation of the Gaussian, in pixels.
amount	numbers.Real	The percentage of the difference between the original and the blur image that is added back into the original
threshold	numbers.Real	The threshold in pixels needed to apply the diffence amount.

Source Image :

Example 1:

# import Image from wand.image module
from wand.image import Image
  
# Read image using Image function
with Image(filename ="koala.jpeg") as img:
  
    # generating sharp image using unsharp_sharpen() function.
    img.unsharp_mask(radius = 10,
                     sigma = 4,
                     amount = 1,
                     threshold = 0)
    img.save(filename ="unsharpmaskkoala.jpeg")

Output:

Example 2: Increasing threshold value to 0.5 and dicreasing radius and sigma.

# import Image from wand.image module
from wand.image import Image
  
# Read image using Image function
with Image(filename ="koala.jpeg") as img:
  
    # generating sharp image using unsharp_sharpen() function.
    img.unsharp_mask(radius = 8,
                     sigma = 4,
                     amount = 1,
                     threshold = 0.5)
    img.save(filename ="unsharpmaskkoala.jpeg")

Output:

Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course. And to begin with your Machine Learning Journey, join the Machine Learning – Basic Level Course

My Personal Notes

Related Articles

Wand unsharp_mask() function – Python