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Combating the Use of AI in Image Manipulation

Building smarter tools to expose smarter fakes.

  • Media forensics
  • Deepfakes

Artificial Intelligence has transformed how we create and edit images, for better and for worse. While tools like DALL-E and Stable Diffusion enable creative expression, they also blur the line between real and fake.

Goal

This research takes on the challenge of AI manipulated images by developing:

  • A large-scale dataset of AI-manipulated images

  • A deep learning detection model that identifies and localizes AI-based edits

Our Contributions

  1. The NCL-IMD.v1 Dataset

We built a dataset of 14,000+ AI-manipulated images, each paired with ground truth masks that show exactly where alterations occurred.

Created using Blended Latent Diffusion, a state-of-the-art text-guided inpainting model.

Includes a wide range of image contexts, mask sizes, and manipulation types.

Publicly available: MediaTrust Dataset

  1. A New Detection Model

We proposed a CNN-based Autoencoder architecture designed specifically to detect manipulations made by diffusion models — where existing models (like MM-Fusion) fail.

Outperforms MM-Fusion on AI-generated images.

F1 score improved from 0.27 → 0.50, with high accuracy (≈96%).

How We Built the Dataset

The data generation process was fully automated:

  • Mask Generator – creates random, human-like selection areas on images.

  • Prompt Generator – uses CLIP + GPT4All (Mistral Instruct) to generate text prompts describing modifications.

  • Image Manipulation – applies Blended Latent Diffusion to generate localized edits.

  • Balancing & Splitting – ensures diverse, balanced data across train/validation/test sets.

Total output: 13,614 high-resolution manipulated images Each image has an associated binary mask indicating the edited regions.

Model Development

Existing detectors (like TruFor and MM-Fusion) perform well on traditional photo edits but struggle with AI-generated content — especially diffusion-based manipulations.

We designed a VGG19-based Autoencoder optimized for anomaly detection in image space.

Removed weaker modalities (e.g., Noiseprint++)

Trained on the NCL-IMD.v1 dataset

Used Mean Squared Error (MSE) loss for stable convergence

The result was a faster, more reliable, and explainable model for identifying AI edits.

Results

Model F1 Accuracy Precision Recall MM-Fusion (default) 0.28 0.85 0.33 0.71 MM-Fusion (retrained) 0.23 0.65 0.16 0.56 CNN-Autoencoder (ours) 0.50 0.96 0.53 0.55

Our Autoencoder model more than doubled the detection performance on diffusion-generated images compared to existing approaches.

Why It Matters

TODO

Key Takeaways

Diffusion-based image edits are fundamentally harder to detect than GAN-based ones.

Prompt quality affects realism — weak text inputs can cause unrealistic or stylistic artifacts.

A data-centric approach (building large, balanced datasets) is crucial for progress in forensic AI research.

Looking Ahead

Improve realism of generated manipulations using next-gen diffusion models.

Refine prompt generation for context-aware edits.

Combine visual and semantic features for hybrid detection.

Develop open benchmarks for evaluating AI manipulation detection globally.