A determination if an image is an original, a reproduction, or even perhaps an artificial manipulation or creation, is a difficult and detailed task. A detailed analysis of the numerous components that comprise the images and sounds must be examined in detail.
Digital files often contain a separate information files known as the file’s metadata. The details contained in the metadata must be examined and cross-referenced for consistency and validity.
The metadata often contains information of when, where, what equipment was employed, and even who captured the image. If the metadata is consistent with all other values comprising the digital image, it can act as a verification stamp for the recording.
But metadata can be easily manipulated to create a believable counterfeit. A detailed examination of the various values in the metadata will align numerous factors in order to resolve or reject the validity of the digital recording.
Other methodologies for authentication include PRNU (Photo Response Non-Uniformity) and PCE (Peak- to-Correlation Energy. These analyses compare an image from a known camera image device to groups of images contained in the video under analysis. These techniques produce tables where patterns are compared from the original to the test image indicating where the authenticity of video recordings is at a variance and therefore suspect.