Lighting and Optical Tools for Image Forensics
Ph.D. dissertation, Dartmouth College
Abstract
We present new forensic tools that are capable of detecting traces of tampering
in digital images without the use of watermarks or specialized hardware. These
tools operate under the assumption that images contain natural properties from a
variety of sources, including the world, the lens, and the sensor. These
properties may be disturbed by digital tampering and by measuring them we can
expose the forgery. In this context, we present the following forensic tools:
(1) illuminant direction, (2) specularity, (3) lighting environment, and (4)
chromatic aberration. The common theme of these tools is that they exploit
lighting or optical properties of images. Although each tool is not applicable
to every image, they add to a growing set of image forensic tools that together
will complicate the process of making a convincing forgery.