create_test_images.py

import cv2
import numpy as np
from skimage import io


def add_debris(img, n_debris=40, seed=None):
    rng = np.random.default_rng(seed)
    h, w = img.shape[:2]
    out = img.copy()
    mask = np.zeros((h, w), dtype=np.uint8)

    for _ in range(n_debris):
        cx = rng.integers(10, w - 10)
        cy = rng.integers(10, h - 10)
        radius = int(rng.choice(np.concatenate([
            rng.integers(20, 40,   size=6),  # small specks
            rng.integers(40, 60,  size=3),  # medium
            rng.integers(100, 120, size=1),  # occasional big chunk
        ])))

        # irregular blob via random polygon
        n_pts  = rng.integers(6, 14)
        angles = np.linspace(0, 2 * np.pi, n_pts, endpoint=False)
        angles += rng.uniform(-0.2, 0.2, n_pts)
        radii  = radius * rng.uniform(0.5, 1.4, n_pts)
        pts = np.stack([
            cx + radii * np.cos(angles),
            cy + radii * np.sin(angles)
        ], axis=1).astype(np.int32)

        cv2.fillPoly(out, [pts], color=(10, 10, 10))
        cv2.fillPoly(mask, [pts], color=255)

    return out, mask
img = io.imread("data/original.tiff")[:, :, :3]

for i in range(10):
    dirty, mask = add_debris(img, n_debris=60)
    io.imsave(f"data/test/dirty{i}.tiff", dirty)