How to Add a Circular Overlay to a Segmented Image in Python

What will you learn?

Discover how to seamlessly incorporate a circular overlay onto a segmented image using Python. This tutorial delves into the realm of image manipulation, offering insights into enhancing images with code.

Introduction to the Problem and Solution

Working with images in Python presents an exciting array of possibilities, ranging from basic editing tasks like cropping and resizing to more complex operations such as segmentation and overlaying shapes. In this scenario, the objective is to enhance an already segmented image by adding a circular overlay. This can serve various purposes, including highlighting specific regions or enhancing visual appeal.

To accomplish this task, we will utilize Python’s robust imaging libraries, primarily Pillow (PIL Fork) for basic image handling, along with matplotlib or OpenCV for advanced manipulations like drawing shapes over images. The process involves loading the target image into memory, defining the parameters of the circle (such as diameter and position), and finally drawing the circle directly onto the image. By following these steps, you will gain practical experience with essential functions for manipulating image properties and rendering graphics on them.


from PIL import Image, ImageDraw

# Load your segmented image
image_path = 'path/to/your/image.jpg'
image =

# Define circle parameters: position(x,y) and radius
circle_position = (100, 100)
circle_radius = 50

# Create a drawing context from the image
draw = ImageDraw.Draw(image)

# Draw the circle on your image - replace 'red' with any color of choice
              circle_position[1]+circle_radius], outline='red')

# Save or display your modified image

# Copyright PHD


In this solution: – Import Image for opening files and ImageDraw for drawing functionalities from PIL. – Load the pre-segmented image using – Define the circular overlay’s position (circle_position) and size (circle_radius). – Instantiate an object (draw) that enables interaction with PIL drawing commands. – Utilize .ellipse() to draw an ellipse shape on the image based on specified coordinates and styling parameters. – Display or save the modified image showcasing the newly integrated circular highlight.

This approach exemplifies how programmatically manipulating images facilitates personalized content creation through automation scripts.

  1. How do I install Pillow?

  2. To install Pillow, use:

  3. pip install Pillow
  4. # Copyright PHD
  5. Can I change the color of my circle?

  6. Yes! Modify ‘red’ in draw.ellipse() function call to any valid CSS color name or hexadecimal code.

  7. What if I want a filled-in circle instead of just an outline?

  8. Include both ‘outline’ and ‘fill’ arguments in .ellipse(). For example: ‘fill=”blue”‘.

  9. Is there support for anti-aliased circles?

  10. While direct support via PIL alone is limited, combining it with libraries like OpenCV may yield smoother results.

  11. Can I create transparent circles?

  12. Certainly! Use RGBA mode when creating your initial Image object (mode=’RGBA’), then set transparency through alpha channel values within colors.

  13. How do I save my modified picture?

  14. Save your modified picture using .save(‘path/to/save/image.jpg’).


Enhancing visuals by overlaying elements onto existing media adds dynamic layers that significantly amplify their narrative impact. By employing concise yet potent lines of code segments like these, remarkable enhancements effortlessly breathe new life into digital creations across various landscapes´┐Żensuring engagement remains both captivating and relevant.

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