Compression Artifact Analysis
JPEG Forensics
Analyzes JPEG compression artifacts to estimate quality levels and detect re-compression patterns that indicate image manipulation or AI generation.
Frequently Asked Questions
How is JPEG quality estimated?
By analyzing DCT coefficients in 8x8 blocks and comparing quantization patterns. Different JPEG quality settings produce distinctive coefficient distributions.
What are blocking artifacts?
JPEG compresses in 8x8 pixel blocks. Heavy compression creates visible block boundaries. AI output often lacks these natural JPEG artifacts or has unusual patterns.
Can you detect double compression?
Yes, re-saving a JPEG creates distinctive dual patterns in DCT histograms. This helps identify manipulated images that were saved multiple times.
Why do AI images have different compression patterns?
AI generates images at the pixel level without camera-like compression. When saved as JPEG, the compression patterns differ from camera-originated images.
Does PNG format bypass this detection?
PNG uses lossless compression, so this specific method doesn't apply. However, other detection methods work on PNG files effectively.
What is quantization noise analysis?
JPEG quantization introduces specific noise patterns. Camera sensors add their own noise on top. AI images lack this layered noise characteristic.
How does multiple re-saves affect detection?
Each re-save adds compression artifacts. Real photos typically show 1-2 compression generations; AI shared on social media may show many more.
What JPEG quality range is most informative?
Quality 70-90% provides the best balance. Higher quality has fewer artifacts to analyze; lower quality obscures original characteristics with heavy compression.
Is this effective against all AI models?
Yes, regardless of the AI model used, the output format determines compression patterns. All AI images show non-camera-like compression when saved as JPEG.
Why is the weight only 7%?
Compression patterns can be altered by format conversion and social media processing. This makes them less reliable than content-based methods, hence the lower weight.
Méthodes associées
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Analyse PRNU
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Analyse Fréquentielle
L'analyse du domaine fréquentiel examine la distribution des composantes haute et basse fréquence d'une image. Les images générées par IA manquent généralement du bruit naturel haute fréquence présent dans les vraies photographies.
Analyse de gradient
Analyzes edge patterns and texture characteristics using Sobel, Canny, and Laplacian operators. AI images often have unnaturally smooth or uniform gradients.
Motif de bruit
Les vraies photographies contiennent des motifs de bruit uniques des capteurs de caméra qui varient à travers l'image. Les images générées par IA ont une distribution de bruit anormalement uniforme.
Analyse des métadonnées
Les métadonnées d'image contiennent des indices précieux sur son origine. Nous analysons les données EXIF, les signatures logicielles et autres informations intégrées pour identifier les outils de génération IA.
Empreinte GAN
Détecte les artefacts spécifiques aux GAN comme les motifs en damier et le banding couleur.
Analyse de texture
Analyse Local Binary Pattern pour les anomalies de texture dans les images IA.
Détection Anatomique
Les générateurs d'images IA créent souvent des erreurs anatomiques que les humains reconnaissent immédiatement comme fausses. Nous utilisons la vision par ordinateur pour détecter ces erreurs révélatrices.
Vérification C2PA
C2PA (Coalition for Content Provenance and Authenticity) est un standard industriel pour suivre l'origine et l'historique du contenu numérique via des signatures cryptographiques.
Semantic Inconsistency Detection
Detects logical inconsistencies like incorrect shadows, impossible perspectives, distorted reflections, and violations of physical laws that AI often produces.
Human Biometric Analysis
Uses MediaPipe to analyze human anatomy for incorrect finger counts, asymmetric eyes, unnatural skin texture, and other anatomical anomalies common in AI-generated faces.
Lighting Physics Validation
Validates light source consistency, shadow direction physics, specular highlight accuracy, and color temperature uniformity across the image.
Edge Sharpness Analysis
Analyzes sharpness distribution across the image and validates depth-of-field consistency. AI often produces unnaturally uniform sharpness.
Statistical Pattern Analysis
Analyzes statistical properties including Shannon entropy, histogram patterns, and Benford's Law compliance to detect synthetic image characteristics.
Chromatic Aberration Analysis
Detects the absence of chromatic aberration (color fringing) that real camera lenses produce. AI images lack these optical artifacts.
Micro-Texture Analysis
Analyzes microscopic texture patterns for repetition, uniformity, and unnatural randomness that AI generators often exhibit.
Color Palette Analysis
Analyzes color distribution including saturation levels, color diversity, and white balance consistency. AI images often have oversaturated colors.
Vérifier Votre Image
Toutes les méthodes sont combinées en utilisant un score pondéré pour produire un verdict final avec niveau de confiance.
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