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correlation coefficient<br />

Was it your camera that took this image?<br />

◮ cameras are identified by measuring the similarity of the noise residual of a<br />

questionable image and all known reference noise pattern<br />

⊲ correlation coefficient or (more preferably) peak to correlation energy<br />

0.3<br />

0.2<br />

0.1<br />

0<br />

reference pattern: S70<br />

Canon S70<br />

Canon S45<br />

Epson 1240U<br />

Ixus IIs<br />

1 image index<br />

350<br />

Closed camera set problem:<br />

◮ choose the camera with the highest<br />

similarity<br />

Open camera set problem:<br />

◮ no decision if maximum similarity is<br />

below a certain threshold<br />

◮ large-scale test with more than 10 6 images from ≈ 7000 individual cameras:<br />

97.6 % correct identification at a false acceptance rate of < 3 × 10 −5 [Goljan et al., 2009]<br />

Gloe & Kirchner Digital Image Forensics slide 28

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