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【期刊论文】A High Capacity Steganography Scheme for JPEG2000 Baseline System
吴仁彪, Liang Zhang, Haili Wang, Renbiao Wu.
IEEE Transactions on Image Processing, 2009, Vol.18, No.8, pp.1797-1803.,-0001,():
-1年11月30日
Hiding capacity is very important for efficient covert communications. For JPEG2000 compressed images, it is necessary to enlarge the hiding capacity because the available redundancy is very limited. In addition, the bitstream truncation makes it difficult to hide information. In this paper, a high-capacity steganography scheme is proposed for the JPEG2000 baseline system, which uses bit-plane encoding procedure twice to solve the problem due to bitstream truncation. Moreover, embedding points and their intensity are determined in a well defined quantitative manner via redundancy evaluation to increase hiding capacity. The redundancy is measured by bit, which is different from conventional methods which adjust the embedding intensity by multiplying a visual masking factor. High volumetric data is embedded into bit-planes as low as possible to keep message integrality, but at the cost of an extra bit-plane encoding procedure and slightly changed compression ratio. The proposed method can be easily integrated into the JPEG2000 image coder, and the produced stego-bitstream can be decoded normally. Simulation shows that the proposed method is feasible, effective, and secure.
Covert communication,, information hiding,, JPEG2000,, steganography.,
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【期刊论文】Motion compensation for UAV SAR based on raw radar data
吴仁彪, Mengdao Xing, Xiuwei Jiang, Renbiao Wu, Feng Zhou, Zheng Bao.
IEEE Transactions on Geoscience and Sensing, 2009, Vol.47, No.8, pp.2870-2883.,-0001,():
-1年11月30日
Unmanned aerial vehicle (UAV) synthetic aperture radar (SAR) is very important for battlefield awareness. For SAR systems mounted on a UAV, the motion errors can be considerably high due to atmospheric turbulence and aircraft properties, such as its small size, which makes motion compensation (MOCO) in UAV SAR more urgent than other SAR systems. In this paper, based on 3-D motion error analysis, a novel 3-D MOCO method is proposed. The main idea is to extract necessary motion parameters, i.e., forward velocity and displacement in line-of-sight direction, fromradar raw data, based on an instantaneous Doppler rate estimate. Experimental results show that the proposed method is suitable for low- or medium-altitude UAV SAR systems equipped with a low-accuracy inertial navigation system.
Motion compensation (, MOCO), ,, radar imaging,, synthetic aperture radar (, SAR), ,, unmanned aerial vehicle (, UAV), .,
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吴仁彪, Xiayu Zheng, Stoica, P., Jian Li, Renbiao Wu.
IEEE Transactions on Signal Processing, 2008, Vol.56, No.4, pp.1589-1600.,-0001,():
-1年11月30日
We present an adaptive detection (AD) for broadband communication in the presence of co-channel interference (CCI). In the case of imperfect channel estimation, a robust AD (RAD) is proposed to maintain the good performance. We also show that both AD and RAD can be further improved by using an iterative scheme, referred to as iterative AD (IAD) and iterative RAD (IRAD), respectively. Numerical examples show that all the proposed methods outperform the conventional maximum likelihood sequence estimator (MLSE) significantly, and that they are also computationally more efficient.
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【期刊论文】Space-time adaptive monopulse processing for airborne radar in non-homogeneous environments
吴仁彪, Renbiao Wu, Zhigang Su, Lu Wang.
International Journal of Electronics and Communications, 2011, Vol.65, No.3, pp.258-264.,-0001,():
-1年11月30日
Space-Time Adaptive Processing (STAP) can be used in combination with monopulse techniques for the estimation of spatial and temporal parameters of moving targets in airborne radar. However, in non-homogeneous environment, the available amount of secondary data which have the same statistical characteristics with the clutter in the primary data is very limited. In this case, the optimum STAP is impractical. In this paper, by combining linearly constrained monopulse technique with STAP, a Reduced Dimension Spatial and Temporal Parameter Estimation (referred to as RD-STPE) method is proposed. Simulation results show that, in non-homogeneous environments, the proposed method can improve the estimation accuracy of the target parameters dramatically, and is more robust than the full dimension adaptive monopulse method with STAP.
airborne radar,, parameter estimation,, monopulse technique,, space-time adaptive processing (, STAP), ,, nonhomogeneous clutter
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吴仁彪, Hai Li, Renbiao Wu.
EURASIP Journal on Advances in Signal Processing, 2013, Vol. 2013, No. 27, pp. 1-11.,-0001,():
-1年11月30日
In this article, we propose a method to estimate the synthetic aperture radar interferometry (InSAR) interferometric phase based on the model of correlation weight joint pixel by using the joint subspace projection technique. In the method, the correlation weight joint data vector is constructed and the data vector can make the noise subspace dimension of the corresponding weight covariance matrix which is not affected by the coregistration error, thus avoiding the trouble of calculating the noise subspace dimension before estimating the InSAR interferometric phase. The method takes advantage of the coherence information of neighboring pixel pairs to auto-coregister the SAR images and employs the projection of the joint signal subspace onto the corresponding joint noise subspace to estimate the terrain interferometric phase. The method can auto-coregister the SAR images and reduce the interferometric phase noise simultaneously. Theoretical analysis and computer simulation results show that the method can provide accurate estimate of the interferometric phase (interferogram) even when the coregistration error reaches one pixel. The effectiveness of the method is verified via simulated data and real data.
SAR interferometry (, InSAR), ,, Joint subspace projection,, Interferometric phase,, Noise subspace,, Correlation weight joint data vector
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