190 research outputs found
Localization of JPEG double compression through multi-domain convolutional neural networks
When an attacker wants to falsify an image, in most of cases she/he will
perform a JPEG recompression. Different techniques have been developed based on
diverse theoretical assumptions but very effective solutions have not been
developed yet. Recently, machine learning based approaches have been started to
appear in the field of image forensics to solve diverse tasks such as
acquisition source identification and forgery detection. In this last case, the
aim ahead would be to get a trained neural network able, given a to-be-checked
image, to reliably localize the forged areas. With this in mind, our paper
proposes a step forward in this direction by analyzing how a single or double
JPEG compression can be revealed and localized using convolutional neural
networks (CNNs). Different kinds of input to the CNN have been taken into
consideration, and various experiments have been carried out trying also to
evidence potential issues to be further investigated.Comment: Accepted to CVPRW 2017, Workshop on Media Forensic
Aligned and Non-Aligned Double JPEG Detection Using Convolutional Neural Networks
Due to the wide diffusion of JPEG coding standard, the image forensic
community has devoted significant attention to the development of double JPEG
(DJPEG) compression detectors through the years. The ability of detecting
whether an image has been compressed twice provides paramount information
toward image authenticity assessment. Given the trend recently gained by
convolutional neural networks (CNN) in many computer vision tasks, in this
paper we propose to use CNNs for aligned and non-aligned double JPEG
compression detection. In particular, we explore the capability of CNNs to
capture DJPEG artifacts directly from images. Results show that the proposed
CNN-based detectors achieve good performance even with small size images (i.e.,
64x64), outperforming state-of-the-art solutions, especially in the non-aligned
case. Besides, good results are also achieved in the commonly-recognized
challenging case in which the first quality factor is larger than the second
one.Comment: Submitted to Journal of Visual Communication and Image Representation
(first submission: March 20, 2017; second submission: August 2, 2017
D-Unet: A Dual-encoder U-Net for Image Splicing Forgery Detection and Localization
Recently, many detection methods based on convolutional neural networks
(CNNs) have been proposed for image splicing forgery detection. Most of these
detection methods focus on the local patches or local objects. In fact, image
splicing forgery detection is a global binary classification task that
distinguishes the tampered and non-tampered regions by image fingerprints.
However, some specific image contents are hardly retained by CNN-based
detection networks, but if included, would improve the detection accuracy of
the networks. To resolve these issues, we propose a novel network called
dual-encoder U-Net (D-Unet) for image splicing forgery detection, which employs
an unfixed encoder and a fixed encoder. The unfixed encoder autonomously learns
the image fingerprints that differentiate between the tampered and non-tampered
regions, whereas the fixed encoder intentionally provides the direction
information that assists the learning and detection of the network. This
dual-encoder is followed by a spatial pyramid global-feature extraction module
that expands the global insight of D-Unet for classifying the tampered and
non-tampered regions more accurately. In an experimental comparison study of
D-Unet and state-of-the-art methods, D-Unet outperformed the other methods in
image-level and pixel-level detection, without requiring pre-training or
training on a large number of forgery images. Moreover, it was stably robust to
different attacks.Comment: 13 pages, 13 figure
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