This Python script removes green highlights from PDF documents by converting each page into an image, processing the image to replace green pixels with white, and then saving the cleaned images back into a new PDF. It uses the `PyMuPDF` library for PDF manipulation and `Pillow` for image processing.

pdf_green_remover.py

# /// script
# requires-python = ">=3.13"
# dependencies = [
#     "numpy>=2.2.1",
#     "pillow>=11.1.0",
#     "pymupdf>=1.25.1",
# ]
# ///

import fitz  # PyMuPDF
from PIL import Image
import io
import sys

import numpy as np

def remove_green(image):
    """Convert green pixels to white in a PIL Image using numpy"""
    # Convert image to numpy array
    img_array = np.array(image)
    
    # Separate RGB channels
    r = img_array[:, :, 0]
    g = img_array[:, :, 1]
    b = img_array[:, :, 2]
    
    # Create mask where green is dominant and above threshold
    green_mask = (g > r) & (g > b) & (g > 128)
    
    # Set green pixels to white
    img_array[green_mask] = [255, 255, 255]
    
    # Convert back to PIL Image
    return Image.fromarray(img_array)

def process_pdf(input_pdf, output_pdf):
    """Process PDF: convert pages to images, remove green, save as new PDF"""
    # Open the input PDF
    pdf_document = fitz.open(input_pdf)
    pdf_writer = fitz.open()  # For output PDF
    
    for page_num in range(len(pdf_document)):
        # Get the page
        page = pdf_document.load_page(page_num)
        
        # Convert page to image (300 DPI for good quality)
        pix = page.get_pixmap(matrix=fitz.Matrix(300/72, 300/72))
        img = Image.open(io.BytesIO(pix.tobytes()))
        
        # Remove green highlights
        cleaned_img = remove_green(img)
        
        # Convert back to PDF page
        # Save cleaned image to a temporary bytes buffer in PNG format
        img_bytes = io.BytesIO()
        cleaned_img.save(img_bytes, format='JPEG')
        img_bytes.seek(0)
        
        # Create new PDF page and insert the image
        pdf_page = pdf_writer.new_page(width=cleaned_img.width, height=cleaned_img.height)
        pdf_page.insert_image(pdf_page.rect, stream=img_bytes)
    
    # Save the output PDF
    pdf_writer.save(output_pdf)
    pdf_writer.close()
    pdf_document.close()

if __name__ == "__main__":
    if len(sys.argv) != 3:
        print("Usage: python pdf_green_remover.py input.pdf output.pdf")
        sys.exit(1)
    
    input_pdf = sys.argv[1]
    output_pdf = sys.argv[2]
    
    process_pdf(input_pdf, output_pdf)
    print(f"Processed PDF saved to {output_pdf}")