Generates a PNG image dataset with transparency from a folder with the images + masks. Useful for masked training of a image generation model. Requires pillow library (pip install pillow)

mask2png.py

import os
from PIL import Image

def apply_transparency(source_folder, dest_folder, transparency_level=0.1):
    """
    Apply transparency to images based on their corresponding masks.

    Args:
        source_folder (str): Path to the folder containing images and masks.
        dest_folder (str): Path to the folder where processed images will be saved.
        transparency_level (float): The level of transparency for transparent areas (0.1 means 10% visible).
    """
    # Ensure destination folder exists
    os.makedirs(dest_folder, exist_ok=True)

    # Supported image formats
    supported_formats = {".jpg", ".jpeg", ".png", ".bmp", ".tiff", ".webp"}

    # Iterate over files in the source folder
    for file_name in os.listdir(source_folder):
        file_ext = os.path.splitext(file_name)[1].lower()
        if file_ext in supported_formats and not file_name.endswith("-masklabel.png"):
            # Build paths for the image and its mask
            image_path = os.path.join(source_folder, file_name)
            mask_name = os.path.splitext(file_name)[0] + "-masklabel.png"
            mask_path = os.path.join(source_folder, mask_name)

            if os.path.exists(mask_path):
                # Open the image and its mask
                image = Image.open(image_path).convert("RGBA")
                mask = Image.open(mask_path).convert("L")

                # Create a new image with adjusted transparency
                transparent_image = Image.new("RGBA", image.size)
                for y in range(image.size[1]):
                    for x in range(image.size[0]):
                        r, g, b, a = image.getpixel((x, y))
                        mask_value = mask.getpixel((x, y))

                        if mask_value == 0:  # Black in mask
                            alpha = int(a * transparency_level)
                            transparent_image.putpixel((x, y), (r, g, b, alpha))
                        else:  # White in mask
                            transparent_image.putpixel((x, y), (r, g, b, 255))

                # Save the processed image to the destination folder
                save_name = os.path.splitext(file_name)[0] + ".png"
                save_path = os.path.join(dest_folder, save_name)
                transparent_image.save(save_path, "PNG")
                print(f"Processed and saved: {save_path}")

if __name__ == "__main__":
    import argparse

    # Parse command-line arguments
    parser = argparse.ArgumentParser(description="Apply transparency to images based on masks.")
    parser.add_argument("source_folder", type=str, help="Path to the source folder containing images and masks.")
    parser.add_argument("dest_folder", type=str, help="Path to the destination folder where processed images will be saved.")
    parser.add_argument("--transparency_level", type=float, default=0.1, help="Level of transparency for transparent areas (default: 0.1).")

    args = parser.parse_args()

    # Run the script with the provided arguments
    apply_transparency(args.source_folder, args.dest_folder, args.transparency_level)