README.md

---
license: agpl-3.0
tags:
  - object-detection
  - yolo
  - yolo11
  - watermark-detection
  - image-processing
  - ultralytics
pipeline_tag: object-detection
---

# BMD Watermark Detector — `bmd_watermark_n.pt`

A lightweight **YOLO11-nano** model fine-tuned for detecting watermarks in images. Trained from scratch on a custom dataset of real-world watermarked images, designed to power the smart-crop watermark removal pipeline in [DatasetStudio](https://github.com/BitcrushedHeart/DatasetStudio).

The `n` suffix denotes the **nano** variant — optimised for fast batch inference on large image datasets without sacrificing meaningful detection accuracy.

---

## Model Details

| Property | Value |
|---|---|
| **Architecture** | YOLO11n (nano) |
| **Task** | Object Detection |
| **Input** | RGB images (any resolution — resized to 640×640 internally) |
| **Output** | Bounding boxes (xyxy) + confidence scores |
| **Classes** | `0: watermark` |
| **License** | [AGPL-3.0](https://www.gnu.org/licenses/agpl-3.0.html) |

---

## Intended Use

This model is intended to **detect the location of watermarks** in images so that a downstream cropping step can remove them cleanly. It is well-suited for:

- Batch processing large image datasets to remove corner/edge watermarks
- Automated dataset cleaning pipelines
- Identifying watermark position (top-left, bottom-right corner, etc.)

> [!WARNING]
> This model is intended for **legitimate dataset cleaning** use cases (e.g. removing watermarks from your own content). Do not use it to strip copyright protections from images you do not have the rights to modify.

---

## Usage

### Requirements

```bash
pip install ultralytics pillow
```

### Basic Inference

```python
from ultralytics import YOLO

model = YOLO("bmd_watermark_n.pt")

results = model("your_image.jpg", conf=0.25)
for r in results:
    for box in r.boxes:
        print(f"Watermark detected at {box.xyxy[0].tolist()} (conf: {float(box.conf[0]):.2f})")
```

### Batch Inference

```python
from ultralytics import YOLO

model = YOLO("bmd_watermark_n.pt")

image_paths = ["img1.jpg", "img2.jpg", "img3.png"]
results = model(image_paths, conf=0.25, verbose=False)

for path, r in zip(image_paths, results):
    if len(r.boxes) > 0:
        print(f"{path}: watermark found")
    else:
        print(f"{path}: clean")
```

### Smart Crop (remove watermark by cropping)

```python
from ultralytics import YOLO
from PIL import Image

def crop_out_watermark(img_path, model, conf=0.25, padding=0.1):
    results = model(img_path, conf=conf, verbose=False)
    r = results[0]
    img_w, img_h = r.orig_shape[1], r.orig_shape[0]

    if len(r.boxes) == 0:
        return Image.open(img_path)  # No watermark, return as-is

    # Find largest detected box
    best_box = max(r.boxes, key=lambda b: (b.xyxy[0][2]-b.xyxy[0][0]) * (b.xyxy[0][3]-b.xyxy[0][1]))
    x1, y1, x2, y2 = best_box.xyxy[0].tolist()

    # Add padding
    pw = (x2 - x1) * padding
    ph = (y2 - y1) * padding
    x1, y1, x2, y2 = max(0,x1-pw), max(0,y1-ph), min(img_w,x2+pw), min(img_h,y2+ph)

    # Crop to the largest region not containing the watermark
    candidates = [
        (0, 0, img_w, int(y1)),        # above
        (0, int(y2), img_w, img_h),    # below
        (0, 0, int(x1), img_h),        # left
        (int(x2), 0, img_w, img_h),    # right
    ]
    best = max(candidates, key=lambda c: (c[2]-c[0]) * (c[3]-c[1]))

    img = Image.open(img_path)
    return img.crop(best)

model = YOLO("bmd_watermark_n.pt")
clean = crop_out_watermark("watermarked.jpg", model)
clean.save("clean.jpg")
```

---

## Training

- **Base architecture:** YOLO11n (Ultralytics)
- **Training data:** Custom dataset of watermarked images with manual bounding box annotations
- **Annotation format:** YOLO format (normalised `class x_center y_center width height`)
- **Hardware:** GPU-accelerated training
- **Recommended confidence threshold:** `0.25` for single-image preview, `0.5` for batch processing

---

## Limitations

- Optimised for **corner and edge watermarks** (bottom-right, bottom-left, top-right, top-left). Centered full-image watermarks (overlays) are out of scope.
- Performance may degrade on very small watermarks (< ~3% of image area) or heavily blended semi-transparent watermarks.
- The nano variant trades some accuracy for speed. For higher accuracy at the cost of inference time, consider training an `s` or `m` size variant.

---

## License

This model is released under the **[AGPL-3.0 License](https://www.gnu.org/licenses/agpl-3.0.html)**, consistent with the Ultralytics YOLO11 framework used for training.

If you use this model in a commercial product or networked service, you must either comply with AGPL-3.0 (open-source your application) or obtain a separate commercial license from Ultralytics for the underlying framework.