This paper presents a reversible fragile data hiding scheme for tampering detection in remote sensing images
based on the histogram shifting approach. The image to be protected is divided into blocks of a reduced size and
a subset of the image bands are selected for embedding. Instead of using the histogram of each separate band,
the shifting process is applied to the histogram of the maximum component (or infinity norm) of the vectors
obtained with the selected bands. The proposed approach is reversible and thus, the original image can be fully
recovered once it has been authenticated. The method is designed to detect specific forged blocks (areas) of
the protected image and is shown to succeed to detect copy and replace attacks. In addition, the experimental
results, presented for the Cuprite AVIRIS image, show that the method yields extremely high transparency, with
PSNR larger than 100 dB prior to reversing the scheme and recovering the original image.
In this paper, a semi-fragile watermarking scheme specifically developed for remote sensing images is presented.
The method can be tuned to embed the mark depending on the content and the signature to be protected. The
suggested method is based on tiling the original three-dimensional images into blocks of different sizes according
to the relevance of the area to protect (bigger blocks are used for less relevant areas). For each of these blocks,
the discrete Wavelet transform (DWT) is applied to each selected spectral band and the obtained LL DWT
sub-bands are used to build a Tree-Structured Vector Quantization tree. This tree is then modified using an
iterative algorithm until it satisfies some criterion. Once the target value is reached, the marked block is obtained
using the new LL DWT sub-band together with the other original sub-bands (LH, HL and HH) of the block.
A secret key produces a different criterion for each block in order to avoid copy-and-replace attacks. The use
of the LL DWT sub-band for each spectral band makes it possible to obtain robustness against near-lossless
compression attacks and, at the same time, relatively strong modifications are detected as tampering.
The M5 Field stabilization Unit (M5FU) for European Extremely Large Telescope (E-ELT) is a fast correcting optical
system that shall provide tip-tilt corrections for the telescope dynamic pointing errors and the effect of atmospheric tiptilt
and wind disturbances.
A M5FU scale 1 demonstrator (M5FU1D) is being built to assess the feasibility of the key elements (actuators, sensors,
mirror, mirror interfaces) and the real-time control algorithm. The strict constraints (e.g. tip-tilt control frequency range
100Hz, 3m ellipse mirror size, mirror first Eigen frequency 300Hz, maximum tip/tilt range ± 30 arcsec, maximum tiptilt
error < 40 marcsec) have been a big challenge for developing the M5FU Conceptual Design and its scale 1
The paper summarises the proposed design for the final unit and demonstrator and the measured performances
compared to the applicable specifications.
In this paper a novel semifragile watermarking scheme for images with multiple bands is presented. We propose to use the remote sensing image as a whole, using a vector quantization approach, instead of processing each band separately. This scheme uses the signature of the multispectral or hyperspectral image to embed the mark in it and detects a modification of the original image, e.g. a replacement of a part of the image into the same image or any other similar manipulation. A modification of the image means to modify the signature of each point, all the bands simultaneously, because in multispectral images it does not have sense to modify a single band of all those that compose the multispectral image. The original multispectral or hyperspectral image is segmented in three-dimensional blocks and, for each block, a tree structured vector quantizer is built, using all bands at the same time. These trees are manipulated using an iterative algorithm until the resulting image compressed by the manipulated tree satisfies all the imposed conditions by such tree, which represents the embedded mark. Each tree is partially modified accordingly to a secret key in order to avoid copy-and-replace attacks, and this key determines the internal structure of the tree and, also, the resulting distortion, in order to make the resulting image robust against near-lossless compression. The results show that the method works correctly with multispectral and hyperspectral images and detects copy-and-replace attacks from segments of the same image and basic modifications of the marked image.
This paper presents a benchmark assessment of the WAUC digital audio watermarking scheme, which relies on MPEG 1 Layer 3 compression to determine where and how the embedded mark must be introduced. The mark is embedded by modifying the magnitude of the spectrum at several frequencies which are chosen according to the difference between the original and the compressed audio content. The main advantage of the scheme is that the perceptual masking of the compressor is implicitly used and, thus, the scheme can be directly tested with different maskings by replacing the compressor. Since repeat coding of the mark is used, a majority voting scheme is applied to improve robustness. The scheme also uses a dual Hamming error correcting code for the embedded mark, which makes it possible to apply it for fingerprinting, achieving robustness against the collusion of two buyers. Several tuning parameters affect the embedding and reconstruction processes, the values of which are chosen according to the tuning guidelines obtained in previous works. In order to illustrate the robustness of the method, the WAUC scheme has been tested against several evaluation profiles, such as the attacks introduced in the Watermark Evaluation Testbed (WET) for audio.
Conference Committee Involvement (1)
Satellite Data Compression, Communications, and Processing VIII
12 August 2012 | San Diego, California, United States