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SIFT (Scale-Invariant Feature Transform)

Definition

A keypoint descriptor algorithm that detects interest points and computes 128-dimensional descriptors invariant to scale and rotation. In forgery detection, matching SIFT descriptors within a single image identifies regions with identical local structure that would not be present in an authentic photograph.

Related terms

Affine Transform Estimation
The recovery of the geometric transformation (rotation, scaling, shear) relating a copied region to its source, using matched keypoint pairs. Geometrically consistent...
Block-Matching
A copy-move detection strategy that divides the image into overlapping fixed-size blocks, computes a compact feature vector per block, sorts vectors, and...
Chromatic Aberration
Colour fringing at high-contrast edges caused by differential refraction of light wavelengths by a lens. The pattern is lens-specific and inconsistent across...
Copy-Move Forgery
An intra-image manipulation in which a patch copied from one location within the image is pasted over another location in the same...
Localisation Map
The output of a forgery detection algorithm that marks, at pixel or block resolution, which regions of the image are identified as...
Noiseprint
A CNN-based camera-model fingerprint extractor by Cozzolino and Verdoliva. Applied to deepfakes, it reveals inconsistency between the camera fingerprint in the genuine...
Passive Forgery Detection
Detection that operates on the image data alone, without any pre-embedded watermark or signature. Distinguished from active methods such as digital watermarking...
Splicing
An inter-image manipulation in which content from one or more external images is inserted into a target image. Splicing introduces cross-boundary inconsistencies...

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