Image and Video Forensics through Content AnalysisSpeaker: James F. O'Brien – Berkeley, CA, United States
Topic(s): Security and Privacy
Advances in computational photography, computer vision, and computer graphics allow for the creation of visually compelling photographic forgeries. Forged images have appeared in tabloid magazines, main-stream media outlets, political attacks, scientific journals, and the hoaxes that land in our email in-boxes. These doctored photographs are appearing with growing frequency and sophistication, and even experts cannot rely on visual inspection to distinguish authentic images from forgeries.
Techniques in image forensics operate on the assumption that photo-tampering will disturb some statistical or geometric property of an image. In a well-executed forgery these disturbances will either be perceptibly insignificant, or they may be noticeable but subjectively plausible. Methods for forensic analysis provide a means to detect and quantify specific types of tampering. To the extent that these perturbations can be quantified and detected, they can be used to objectively invalidate a photo.
This talk will focus on forensic methods based on geometric content analysis. These methods work by finding inconsistencies in the geometric relationships among objects depicted in a photograph. The geometric relationships in the 2D image correspond to the projection of the relations that exist in the 3D scene. If a scene is known to contain a given relationship but the projected relation does not hold in the photograph, then one may conclude that the photograph is not a true projective image of the scene. The goal is to build a set of hard constraints that must be satisfied or else the image must be fake.
About this LectureNumber of Slides: 90
Duration: 60 minutes
Languages Available: English
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