PRNU
Definition
Photo-Response Non-Uniformity. The per-pixel variation in light sensitivity across a camera sensor, which produces a consistent, device-specific noise pattern in every photograph it takes. Used in traditional camera forensics to attribute a photograph to a specific device.
- Full form
- Photo-Response Non-Uniformity
- Cause
- Per-pixel sensor sensitivity variation
- Property
- Consistent, device-specific pattern
- Forensic use
- Attributing a photograph to a specific camera
Common questions
How is a camera's PRNU pattern extracted for comparison?+
It is estimated by averaging the noise residual across many images known to come from the camera, typically flat-field or plain-scene shots, to cancel out image content and isolate the consistent per-pixel sensitivity fingerprint left by the sensor.
Can PRNU attribution work on a heavily edited or downsized image?+
Attribution grows less reliable as an image is compressed, resized, or filtered, because those operations degrade the fine noise pattern the method depends on; strongly processed images, such as ones repeatedly re-shared on social media, often carry too little usable PRNU signal for confident attribution.
Related terms
- C2PA
- Coalition for Content Provenance and Authenticity. A cross-industry group that has published an open technical specification for embedding cryptographically signed provenance manifests...
- Content Credentials
- Adobe's brand name for C2PA-compliant provenance manifests. A Content Credentials badge on an image indicates that a signed, auditable creation history is...
- GAN Fingerprint
- A model-specific periodic pattern embedded in GAN-generated images, detectable by averaging outputs and subtracting a reference. Analogous to photo-response non-uniformity (PRNU) in...
- Invisible Watermark
- A signal embedded in an image or audio file that is imperceptible to a human viewer but detectable by an algorithm. In...
- Out-of-Distribution (OOD) Failure
- The drop in a classifier's accuracy when test samples come from a different statistical distribution than the training data. AI-generated image detectors...