digital image forensics
DESCRIPTION
Digital Image Forensics. CS 365 By:- - Abhijit Sarang - Pankaj Jindal. Which of them are digitally manipulated?. How can we know?. - PowerPoint PPT PresentationTRANSCRIPT
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Digital Image Forensics
CS 365
By:-- Abhijit Sarang- Pankaj Jindal
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Which of them are digitally manipulated?
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How can we know?
• We call a digital image manipulated if either it has been retouched by a photo editing software or has been produced by the software itself.
• To prevent the former, the owner of the original image may introduce a watermark or a digital signature.
• But this process may not be feasible every time.
• Most approaches for detecting digital image manipulation are blind approaches.
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Our Methodology
• In [1], the authors argue that the statistical artifacts associated with images generated from cameras is inherently different form that associated with images manipulated by a software.
• These properties can be captured by analyzing the noise present in the image.
• Further, a discrete wavelet transform of the image can also be used to obtain some other statistical features .
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Building the feature vectors• Image De-noising
• Image was filtered using a wiener adaptive filter and a median filter.
• Neighborhood model of Wavelet sub bands
• To capture the strong correlation that exists between the wavelet subband coefficient, we find the residual error by building a neighborhood prediction model.
• Discrete wavelet transform
• We find the distance of the sub-bands distribution from the corresponding Gaussian distribution.
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Results
• Image denoising
• True Positive = 37/47
• False Positive = 21/53
• Neighborhood model of Wavelet sub bands
• True Positive = 32/47
• False Positive = 11/53
• Discrete wavelet transform
• True Positive = 34/47
• False positive = 15/53
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Detecting Fake Regions
Detecting abnormal noise patterns in Image Detecting Duplicated Image Regions
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References
Digital image Forensics For Identifying Computer Generated And Digital Camera Images Sintayehu Dehnie, Taha Sencar and Nasir Memon
Exposing Digital Forgeries by Detecting Duplicated Image Regions Alin C Popescu and Hany Farid
Noise Features for Image Tampering Detection and Steganalysis Hongmei Gou, Swaminathan, A., Min Wu
How realistic is photorealistic? Siwei Lyu and Hany Farid