This script converts an image into a pencil sketch using OpenCV.

sketchrizer.py

#!/usr/bin/env python3.11
# -*- coding: utf-8 -*-
"""
Image to Pencil Sketch Converter
================================
This script converts an image into a pencil sketch using OpenCV.
It accepts the image file path as a command-line argument, processes the image,
and saves the pencil sketch as an output file.

Usage:
    python3.11 sketch.py <image_path>

Requirements:
    - Python 3.11
    - OpenCV library (install using `pip3.11 install opencv-python` or `sudo port install py311-opencv4`)

Author: Dzogrim
Date: 2024-11-16
"""

import cv2
import sys

def image_to_pencil_sketch(image_path, output_path="sketch_image.png"):
    """
    Converts an image to a pencil sketch and saves the output.

    Parameters:
        image_path (str): Path to the input image file.
        output_path (str): Path to save the output pencil sketch image. Default is 'sketch_image.png'.

    Returns:
        None
    """
    # Read the input image
    image = cv2.imread(image_path)
    if image is None:
        print("Error: Unable to read the image. Please check the file path.")
        sys.exit(1)

    # Convert the image to grayscale
    gray_image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

    # Invert the grayscale image
    inverted = 255 - gray_image

    # Apply Gaussian blur to the inverted image
    blur = cv2.GaussianBlur(inverted, (21, 21), 0)

    # Invert the blurred image
    inverted_blur = 255 - blur

    # Combine the grayscale and inverted blurred images to create a sketch
    sketch = cv2.divide(gray_image, inverted_blur, scale=256.0)

    # Save the pencil sketch image to the specified output path
    cv2.imwrite(output_path, sketch)
    print(f"Pencil sketch saved to: {output_path}")

    # Display the pencil sketch
    cv2.imshow("Pencil Sketch", sketch)
    cv2.waitKey(0)
    cv2.destroyAllWindows()

if __name__ == "__main__":
    # Ensure the script is called with the correct number of arguments
    if len(sys.argv) != 2:
        print("Usage: python sketch.py <image_path>")
        sys.exit(1)

    # Extract the image path from the command-line arguments
    image_path = sys.argv[1]

    # Call the function to process the image
    image_to_pencil_sketch(image_path)