Blind detection of image manipulation @ PoliMi

Blind detection of image manipulation
Giorgio Sironi, matr. 764852 Politecnico di Milano - Como, January 12th, 2011

Problem statement http://xkcd.com/331

Possible solutions
Automated detection of tampering on non-watermarked images
Pixel-based
Format-based
Camera-based
Physics-based
Geometric-based

Pixel-based techniques
Detection of cloning, resampling , splicing

Format based techniques
Double JPEG , JPEG quantization and blocking

Camera based techniques
Chromatic aberration , sensor noise...

Physics-based
Light direction (2D or 3D)

Geometric-based
Sign manipulations
Assumptions: manual selection, [known font]

What is a photograph?
Camera executes a projective transformation ( homography ). We use projective geometry tools.

Math background
Homegeneous coordinates: O is (0,0,1)... Or (0,0,2), or (0,0,3). (10, 15) is (10, 15, 1) or (20, 30, 2)
Planar homography: 3x3 matrix (linear transformation)

How do we estimate an homography?

How do we find the keypoints?
SIFT: feature detection
RANSAC: matching of keypoints pairs

How do we judge a rectification?
Comparison between (binary) rectified image and world sample(s)

It's an arm race Computer programs support projective geometry tools; do humans?

References Main Hany Farid, A Survey of Image Forgery Detection (2009), in: IEEE Signal Processing Magazine, 2:26(16-25) Valentina Conotter, Giulia Boato and Hany Farid, Detecting Photo Manipulation on Signs and Billboards, in: International Conference on Image Processing, Hong Kong, 2010 R. Hartley and A. Zisserman, Multiple View Geometry in Computer Vision, Cambridge University Press, 2004. D.G. Lowe, “Distinctive image features from scale-invariant keypoints,” International Journal of Computer Vision, vol. 2, no. 60, pp. 91–110, 2004. Minor Prasad S. and K. R. Ramakrishnan, ON RESAMPLING DETECTION AND ITS APPLICATION TO DETECT IMAGE TAMPERING, in: IEEE International Conference on Multimedia and Expo (ICME 2006),, Jul 09-12, 2006, Toronto, Canada, pp. 1325-1328. Micah K. Johnson and Hany Farid, Exposing Digital Forgeries by Detecting Inconsistencies in Lighting (2005), in: MM&Sec '05 Proceedings of the 7th workshop on Multimedia and security Babak Mahdian and Stanislav Saic, A Bibliography on Blind Methods for Identifying Image Forgery (2010), in: Signal Processing: Image Communication, 25:6(389-399) Sevinc Bayram, Husrev T. Sencar and Nasir Memon, A Survey of Copy-Move Forgery Detection Techniques, in: IEEE Western New York Image Processing Workshop, Rochester, NY, 2008 Nitin Khanna, Aravind K. Mikkilineni, Anthony F. Martone, Gazi N. Ali, George T.-C. Chiu, Jan P. Allebach and Edward J. Delp, A Survey of Forensic Characterization Methods for Physical Devices (2006), in: Digital Investigation, 3:Supplement 1(17-28)

Thanks for your attention

http://giorgiosironi.blogspot.com	147
http://www.giorgiosironi.com	12
chrome://feedbar	1
http://feeds.feedburner.com	1
http://giorgiosironi.blogspot.in	1

Blind detection of image manipulation @ PoliMi

by Giorgio Sironi on Jan 19, 2011

Accessibility

Tags

Upload Details

Usage Rights

5 Embeds 162

Statistics

Blind detection of image manipulation @ PoliMi — Presentation Transcript