Remove green background from image using Python

Guide on how to use Python to remove green background (chroma key) from an image using the OpenCV library. This Python code helps in removing green backgrounds to replace it with another background or make it transparent.

import cv2
import numpy as np

def remove_blue_background(image_path, output_path):
    # Read the image from file
    image = cv2.imread(image_path)

    # Convert the image from BGR to HSV
    hsv = cv2.cvtColor(image, cv2.COLOR_BGR2HSV)

    # Define the range for blue color (green screen)
    lower_blue = np.array([35, 100, 100])
    upper_blue = np.array([85, 255, 255])

    # Create a mask to detect the blue areas
    mask = cv2.inRange(hsv, lower_blue, upper_blue)

    # Apply the mask to the image to remove blue background
    result = cv2.bitwise_and(image, image, mask=~mask)

    # Save the resulting image
    cv2.imwrite(output_path, result)

# Example usage
remove_blue_background('input_image.jpg', 'output_image.png')

Detailed explanation:

1. Read the image from file:

   • cv2.imread(image_path): Reads the image from the file path.

2. Convert image to HSV:

   • cv2.cvtColor(image, cv2.COLOR_BGR2HSV): Converts color space from BGR (OpenCV default) to HSV for easier color processing.

3. Define blue color range:

   • lower_blue and upper_blue set the range for blue color in HSV color space. Adjust these values to fit the green screen you are using.

4. Create mask and remove green background:

   • cv2.inRange(hsv, lower_blue, upper_blue): Creates a mask to detect blue color in the image.
   • cv2.bitwise_and(image, image, mask=~mask): Removes the blue areas from the image using the mask.

5. Save the resulting image:

   • cv2.imwrite(output_path, result): Saves the processed image to the output file path.

Python Version:

This code uses the OpenCV library and can run on Python 3.6 and above. Ensure that the OpenCV library is installed, which can be done using pip install opencv-python.