High-frequency detail
Definition
Fine textures, sharp edges, and small text that JPEG compresses poorly. These regions inherently show high ELA values in authentic, unmodified images and must be distinguished from manipulation signals.
Related terms
- Compression equilibrium
- The state of an image region after sufficient JPEG compression cycles at a given quality: further compression at the same quality produces...
- ELA amplification factor
- The multiplier applied to the per-pixel difference before display. A higher factor reveals subtle differences but also amplifies noise, making regions look...
- ELA (Error Level Analysis)
- A passive image forensics technique that re-saves the input image at a chosen JPEG quality and amplifies the per-pixel absolute difference to...
- False positive (ELA)
- An ELA anomaly in a region that was not manipulated, typically caused by high-frequency texture, JPEG artefacts in the original, or camera...
- Saturation
- In ELA context, the condition where a region's error level has reached near-zero, indicating it has already been compressed to near-equilibrium. A...
Explained in
- Error Level Analysis (ELA)Fine textures, sharp edges, and small text that JPEG compresses poorly. These regions inherently show high ELA values in authentic, unmodified images and must...