Wand adaptive_threshold() function – Python

0 0 1 minute read

The adaptive_threshold() function is an inbuilt function in the Python Wand ImageMagick library which is used to apply threshold for each pixel. It is present in class wand.image.

Syntax:
adaptive_threshold(width, height, offset)
Parameters: This function accepts three parameters as mentioned above and defined below:

width: This parameter is used to specify the value of width which is the size of neighboring pixels on the X-axis.

height: This parameter is used to specify the value of height which is the size of neighboring pixels on the Y-axis.

offset: This parameter is used to specify the value of offset which is normalized number between 0.0 and quantum_range.
It forces the pixels to black if values are below offset.

NOTE: quantum_range: It is the maximum value of a color channel that is supported by the ImageMagick library.
Return Value: This function returns the Wand ImageMagick object.

Original Image:

Example 1:

Python3

# Import library from Image 
from wand.image import Image
 
# Import the image
with Image(filename ='../zambiatek.png') as image:
    # Clone the image in order to process
    with image.clone() as adaptive_threshold:
        # Invoke adaptive_threshold function with width as 2, height as 
        # 3 and offset as 2
        adaptive_threshold.adaptive_threshold(2, 3, 2)
        # Save the image
        adaptive_threshold.save(filename ='adaptive_threshold1.jpg')

Output:

Example 2:

Python3

# Import libraries from the wand  
from wand.image import Image
from wand.drawing import Drawing
from wand.color import Color
 
with Drawing() as draw:
    # Set Stroke color the circle to black
    draw.stroke_color = Color('black')
    # Set Width of the circle to 2 
    draw.stroke_width = 1
    # Set the fill color to 'White (# FFFFFF)'
    draw.fill_color = Color('white')
 
    # Invoke Circle function with center at 50, 50 and radius 25
    draw.circle((200, 200), # Center point
                (100, 100)) # Perimeter point
    # Set the font style
    draw.font = '../Helvetica.ttf'
    # Set the font size 
    draw.font_size = 30
     
    with Image(width = 400, height = 400, background = Color('# 45ff33')) as pic:
        # Set the text and its location
        draw.text(int(pic.width / 3), int(pic.height / 2), 'GeeksForGeeks !')
        # Draw the picture
        draw(pic)
        # Invoke adaptive_threshold function with width as 0, Height as 1 and offset as 0.3
        pic.adaptive_threshold(4, 5, 0.7)
        # Save the image 
        pic.save(filename ='adaptive_threshold2.jpg')