最新刊期
卷 35 ， 期 9 ， 2007
- 摘要：Based on real extremely heterogeneous synthetic aperture radar (SAR) urban clutter data and Cramer-Von Mises distance,the goodness-of-fit tests were done via Rayleigh distribution,Weibull distribution,K distribution and G distribution,respectively.It is shown that the Rayleigh distribution and Weibull distribution may be mismatched and the K distribution may be only partly matched,but the G distribution may model the real data very well.Furthermore,for the CFAR(Constant False Alarm Rate) detection under the G distributed clutter,the curves of the signal-to-noise ratio versus shape parameter and numbers of reference cells were presented to meet the given detection performance,and the reason was also analyzed that the CFAR losses decrease with the increasing of the distribution parameter.Also,an effective CFAR threshold calculating method was proposed at last.关键词：G distribution;SAR(Synthetic Aperture Radar);validation of clutter model;CFAR(Constant False Alarm Rate) detection;extremely heterogeneous clutter2|991|7更新时间：2025-07-16
- 摘要：This work addresses the study of bandwidth management and image formation for airborne SAR imaging with 0.1m resolution.The frequency domain synthetic bandwidth method is analyzed,and a novel quasi method that applies to deramp receive mode is proposed.Some issues arising in practical implementation of the technique are discussed,that is,the filter design and the solution to overlap.Different algorithms with integrated motion compensation (ECS/ECZT/EOK) are compared with each other in terms of their focusing processing,and some expressions for allowable range and range scene extent are presented.Moreover,analysis of an approach combining the synthetic bandwidth technique and Omega-K algorithm is presented.It offers the possibility of achievement X-band airborne SAR imaging up to 0.1m resolution.Finally,we present results on simulated data aimed at validating the whole analysis and the proposed procedure.关键词：airborne SAR;high range resolution;synthetic bandwidth;image formation2|1103|2更新时间：2025-07-16
- 摘要：Stepped-frequency radar has the ability of high range resolution(HRR).It normally adopts frequency-time transformation(IDFT) processing to get the range profile of targets.Alternatively stepped-frequency radar can also use time-frequency transformation(DFT) processing, with which it is seen as a kind of pulsed-doppler(PD) radars that use stepped-frequency pulses. Through parametric design and signal processing methods of the radar system,DFT method can achieve both unambiguous velocity and high resolution ranging in a single dwell under HPRF circumstances.The range ambiguity problem in HPRF PD radars can be resolved by careful design of parameters and signal processing methods.This paper analyzes the time-frequency transformation processing of stepped-frequency radars,based on which the HPRF PD stepped-frequency radar system’s parameter design principle,solutions to the frequency-time coupling issue and range ambiguity are also given.Both theoretical analysis and simulation result prove that this radar scheme can simultaneously achieve unambiguous velocity and high resolution ranging.关键词：radar;stepped frequency;time-frequency transformation;waveform analysis;ambiguity resolution3|2060|14更新时间：2025-07-16
- 摘要：The problem of algorithm designing and performance evaluating of polarization recognition of active-decoys and radar targets is studied.Firstly,the received signal models of radar targets and active-decoys to polarimetric radar are presented.Secondly,two local identification statistical tests based on the differences of active-decoys and radar targets are derived.Thirdly,a polarization identification scheme of active-decoys is represented.Finally,statistics of two local identification tests are discussed and the performance of polarization identification algorithm is theoretically analyzed and evaluated.关键词：active-decoy;polarization;recognition;statistical distribution2|1032|6更新时间：2025-07-16
- 摘要：In order to improve the ratio of the attack success in the marine fighting,the enemy’s shipborne Radar should be countermeasure in advance for reducing the detection ability.In this paper,we first analyze the process theory of the radar signal on the jamming background,and then get the relationship between the jamming orientation and characteristic curve.After that,the equation of the multi-jamming resources based on the space energy is created.According to this model,the jamming effected area was simulated and portrayed in 3D by MFC program structure and OpenGL technique.The simulation result is consistent with the theory analysis.关键词：signal detection;jamming area;counter measure;simulation2|1008|2更新时间：2025-07-16
- 摘要：To estimate the parameters in complex noise situation effectively,a new robustness algorithm for adaptive signal process is presented named adaptive recursive M-estimation (ARME).And its properties of convergence,asymptotic unbiasedness and robustness are analyzed from theory and Monte Carlo simulations.Results and simulations show that the ARME algorithm obtains the advantages of the recursive least square (RLS) in Gaussian white noise (WGN).More importantly,in the no-Gaussian noise situation such as WGN with high interference,they show that the ARME algorithm has a better convergence rate and a less estimation deviation than those of the RLS.Besides that,the ARME is more robustness compared with the RLS.关键词：adaptive processing;M-estimation;least square estimation;recursive least square;robustness;Monte Carlo2|1247|2更新时间：2025-07-16
- 摘要：In the passive locating and tracking system of single observer,an obtainment of Doppler Frequency Rate-of-Change is very important for the state estimation and location of a moving target.The Doppler Frequency Rate-of-Change is very difficult to estimate accurately because of its subtleness.Wavelet transform has the time-frequency localization characteristic and low SNR threshold.An algorithm based on wavelet transform is proposed to estimate the Doppler Frequency Rate-of-Change,the computer simulation study shows that this algorithm has low SNR threshold and obtain the parameter estimation fast and accurately.关键词：Doppler frequency rate-of-change;wavelet transform;parameter estimation2|895|3更新时间：2025-07-16
- 摘要：This paper presents a design for increasing spectral efficiency of Pilot Symbol Assisted Modulation(PSAM)-Orthogonal Frequency Division Multiplexing(OFDM) system by the use of segmented data rate transmission in the frequency-selective block fading channel model.In the proposed scheme,the transmitter divides the information-bearing tones of a block into several segments,each of which uses the data rate limited by its lower bound of the mutual information.The receiver detects current segments and uses the detected symbols as the addition pilots for next segment.With the number of the pilot symbols increases,quality of each channel estimate is improved and,consequently,the spectral efficiency of the system can be increased.It is reasonable to assume that the limit of symbol error rate is zero when each segment contains large number of symbols.Under this assumption,we derived the lower bound of the spectral efficiency.The numerical results show the spectral efficiency gain over the conventional design.关键词：spectral efficiency;channel estimate;pilot symbol assisted modulation(PSAM)2|1010|0更新时间：2025-07-16
- 摘要：The presence of non-Gaussian ambient channel noise in wireless systems can degrade the performance of existing blind MUD (MultiUser Detection) method.We investigate the problem of blind MUD in alpha stable distribution noisy communication channels by addressing the negative effects of heavy-tailed noise to the original blind MUD algorithm.This paper proposes a new MOE (Minimum Output Energy) criterion employing FLOS (fractional lower-order statistic).The associated FLOS-MOE blind MUD method,based on a stochastic gradient descent algorithm,is able to mitigate impulsive channel noise and MAI (multiple address interference).Theoretical analyses and the computer simulations indicate that the new detector is not only suitable for Gaussian noise condition,but also robust under impulse noise condition.2|859|5更新时间：2025-07-16
- 摘要：Based on summarizing MUSIC algorithm,the quantitative relationship,that the performance of MUSIC algorithm gets better while array elements spacing becomes longer,was analyzed under the condition of array elements spacing not larger than half wavelength of carrier;the possible occurrence of false peaks was discussed as array elements spacing was larger than half wavelength of carrier,and one solution to pick up true peaks was provided.At last,the conclusions in this paper are verified by simulation experiments.关键词：antenna array;DOA;MUSIC(multiple signal classification) algorithm;array elements spacing;spatial spectrum2|2946|14更新时间：2025-07-16
- 摘要：Cyclostationarity is an important statistical property of many signals,which has just been considered so far under Gaussian noise.In this paper,the degradation of the cyclic property is evaluated in the presence of stable distributed noises.A novel definition of the pth order cyclic correlation is proposed and the cyclic ambiguity function referred to as PCCA (pth order Cyclic Cross-Ambiguity) is developed.Simulation results demonstrate the efficiency of the proposed method in the joint estimation of time delay and Doppler shift understable and Gaussian noise condition.It is a more robust and significant method and its performance is super to CCA(Cyclic Cross-Ambiguity) and FLOAF(Fractional Lower Order Ambiguity Function).关键词：S α S;Doppler shift;fractional lower order moments;ambiguity function2|1064|3更新时间：2025-07-16
- 摘要：In wireless sensor networks (WSN),it is a fundamental issue to balance the two conflicting performance indexes:sensing ability and energy cost.An adaptive and distributive self-organization (SO) algorithm is proposed,in which sensor node in the WSN is mapped to emotional ant in the ant colony system.By this means,the wakeup probability of nodes can then be optimized through the collaboration among ant colonies with swarm intelligence,so as to accomplish efficacious SO of WSN.In addition,the designing method of the performance indexes and relative parameters is depicted in the form of theorem.Simulation results show that the proposed algorithm maintains superior detection ability while waking up fewer nodes to detect.关键词：Wireless sensor networks;swarm intelligence;self-organization;ant colony optimization2|941|7更新时间：2025-07-16
- 摘要：Geographic routing in wireless sensor networks suffers from the local minimum phenomenon. To help packets get out of local minimum phenomenon,the long-known right-hand rule is used,which needs the graphs planarizing. It will lost many links and doesn’t suit adaptive routing. Through studying the local minimum phenomenon deeply,we find out that greedy forwarding in restricting routing regions could deal with the local minimum phenomenon. Based on the observation,a new method Clockwise Rule was proposed,which does not lost any links and more suits adaptive routing. We also proposed an adaptive parallel multi-path routing algorithm (APMR) using Clockwise Rule,which can provide various routing strategies and switch these strategies at relay nodes freely. Simulations show that APMR can significantly improve the performance of wireless sensor networks.关键词：Wireless sensor networks;adaptive multi-path;local minimum phenomenon;geographic routing2|1272|2更新时间：2025-07-16
- 摘要：An audio watermarking algorithm is presented.Robustness of the algorithm is based on the steady positive-negative sign of the DC coefficient in DCT domain.The result of simulation indicates that the algorithm has achieved balance between robustness and imperceptibility.At the same time,an objective measurement associated with psychoacoustic model for measuring the distortion of watermarked audio signal is presented in this paper.The result of experiment and theory analysis indicate that the measurement of imperceptibility matching the human auditory characteristics is an appropriate objective evaluating method.关键词：audio watermarking;discrete cosine transformation;psychoacoustic model;imperceptibility2|1354|7更新时间：2025-07-16
- 摘要：Er3+ doped tungsten-tellurite glass (EDWTZn) is prepared,whose host compositions are WO3,TeO2,ZnO and Na2O.The differential thermal analysis shows that compared with the traditional glasses,the thermal stability of EDWTZn glass is higher.The results analyzed by McCumber theory also show that the peak stimulated emission cross section and the FWHM of EDWTZn glass around 1530nm are 9.52×10-21cm2 and 86nm,respectively.As for the EDWTZn optical fiber amplifier,the results of numerical simulation show that large amplified signals can be obtained with a shorter length of fiber,and about 70nm flat gain band around 1530nm can be provided.关键词：Er3+-doped tungsten-tellurite glass;emission cross section;EDFA;gain;rate equation;propagation equation2|868|0更新时间：2025-07-16
- 摘要：The techniques based on digital signal processing have been applied to analyze and identify the genes in a DNA (deoxyribonucleic acid) sequence.According to period 3bp (base pair) of gene sequences,a new FIR (finite impulse response) digital filter with narrow band-pass response was proposed to predict protein coding regions.The prediction curve of exons was obtained by processing the DNA sequence.Compared with the existing IIR (infinite impulse response) digital filter,the FIR filter can yield better results.关键词：FIR digital filter;IIR digital filter;gene prediction2|1071|4更新时间：2025-07-16
- 摘要：In order to solve the problems of face detection under rotation in image plane and facial features localization,a hierarchical approach was presented.Corner detection,AdaBoost algorithm and C-V method were integrated into the approach.First,four kinds of detectors were trained by AdaBoost algorithm for detecting faces,eyes,noses and mouths.Second,the corners were extracted from image.The corners were regarded as candidate eyes and used to construct candidate face regions as input to the face detector.Third,the eye regions,nose regions and mouth regions were detected using the feature detectors,and the feature contours and feature points were extracted from the feature regions by C-V method.The experiments on CMU rotated face test set result a 94.6% correct rate with 24 false alarms,and the position of the extracted feature points were accurate.Results show that the proposed approach is efficient.关键词：face detection;facial feature localization;corner detection;level set method;C-V method2|1152|5更新时间：2025-07-16
- 摘要：We present a timer-based distributed clustering algorithm.By adaptively adjusting the wakeup rate of the exponential distribution,a node with higher residual energy is more likely to be elected clusterhead.Moreover,the algorithm is able to ensure that clusterheads are well scattered.Simulation experiments illustrate that our algorithm is able to significantly prolong system life compared with previous ones.关键词：Wireless sensor networks;clustering;system life2|1110|8更新时间：2025-07-16
- 摘要：A new video encryption method which utilized Intra,Inter prediction mode scrambling,transform results and motion vector encryption is proposed in this paper based on the formers’ research work.Test showed that this method exhibits nice security;moreover its computational complexity is rather low,has little impact on encoding efficiency and can be realized in real time environment.A video encryption system based on the algorithm is also put up,the fast synchronize of the streaming key and multiple user access is achieved by two-level synchronization and telling mechanism.关键词：video encryption;scrambling;chaos pseudo sequence2|1927|3更新时间：2025-07-16
- 摘要：The performance of equalization in traditional OFDM system is greatly degraded in fast fading channel due to the intercarrier interference (ICI).This paper proposes an adaptive equalization algorithm for OFDM system based on fractional Fourier transform.In this method,the traditional Fourier transform is replaced by fractional Fourier transform to modulate and demodulate the symbols,and the received signals are equalized adaptively in the fractional Fourier domain.The algorithm for selecting the optimal order of fractional Fourier transform is given in this paper.Moreover,the adaptive equalization algorithm in fractional Fourier domain is derived.Theoretical analysis and numerical simulation results show that the proposed equalizer in optimal fractional Fourier domain can significantly improve the performance of OFDM system compared with Fourier domain equalizer.关键词：fractional Fourier transform;OFDM;adaptive equalization2|1155|0更新时间：2025-07-16
- 摘要：We propose a novel joint estimation algorithm for range,frequency,and two-dimensional (2-D) direction-of-arrival (DOA) of each narrowband source in the near field.The proposed method constructs four matrices using the higher-order cumulants of the properly chosen sensor outputs,and forms three new ones using the four matrices,then estimates the source parameters from the new ones’ eigenvalues and the corresponding eigenvectors.In comparison with the conventional methods,the proposed approach efficiently uses the array aperture,and pairs parameters automatically.Finally,the simulation results are presented to validate the performance of the proposed method.关键词：array signal processing;near field source;localization;two-dimensional (2-D) direction-of-arrival(DOA);higher-order cumulant2|915|2更新时间：2025-07-16
- 摘要：A preconditioner is proposed for accelerating solutions of finite element matrix equations.The preconditioner is constructed from a sequence of hierarchical vector spaces spanned by higher order hexahedral basis functions.The preconditioned GMRES algorithm with the precondtioner presented is developed and applied to solve the vector finite element-boundary integral (FE-BI) matrix equations for simulation of scattering from three-dimensional cavities.Numerical results show that the preconditioner for solving the FE-BI systems exhibits superior efficiency and reduced the CPU time significantly.关键词：preconditioner;higher order basis functions;finite element-boundary integral method;scattering2|935|1更新时间：2025-07-16
- 摘要：Validity of small perturbation method (SPM) and high-order SPM (HSPM) is studied by evaluating the emissivity of two-dimensional rough ground and sea surface.The influences of surface model,permittivity and polarization on validity of HSPM and SPM are analyzed.The valid range of root means square (RMS) and correlation length (CL) for HSPM and SPM is obtained from two-dimensional rough surface.Results show that the diversity of different models does not affect the validity of SPM almost,which,however,is not true for HSPM.As for the Gaussian rough surface,the valid range of CL obtained by HSPM is far less than that by SPM.By comparing the simulation results,method of moment results and measured data,it is seen that HSPM is valid.关键词：rough surface;emissivity;high-order small perturbation method;validity2|820|1更新时间：2025-07-16
- 摘要：The water-filling power allocation algorithm can achieve the maximal capacity of multiple-input multiple-output (MIMO) systems with no additional power and bandwidth consumption.Based on Lagrange method,the explicit expression of the water-filling power allocation algorithm for MIMO systems is derived.With the singular value decomposition (SVD) algorithm to the channel impulse response matrix,the capacity analytical equation is derived for MIMO systems with the water-filling power allocation algorithm.Employing the digital beam-forming (DBF) technique,a novel power allocation algorithm is proposed and the capacity equation for MIMO systems with this algorithm is derived.Simulation results show that although the capacity of systems with the proposed power allocation algorithm is slightly smaller than that of systems with the water-filling power allocation algorithm,its computational complexity is lower.关键词：multiple-input multiple-output(MIMO);power allocation;capacity analysis;singular value decomposition(SVD);digital beam-forming(DBF)2|1810|1更新时间：2025-07-16
- 摘要：Small satellite radar dissatisfies the minimum antenna area constraint.Unambiguous SAR imaging of a wide ground area with high azimuth resolution is a contradiction.Under the generalized sampling theorems,nonuniform samples of multiple receiving channels uniquely determine the unambiguous wide bandwidth-limitd signal.A fine resolution unambiguous SAR image can acquired with interpolation.Compared with the array signal processing algorithm for the same purpose,the interpolation algorithm operates more easy and efficiently with high performance.关键词：small satellite;SAR;solve ambiguity;nonuniform sampling2|1005|3更新时间：2025-07-16
- 摘要：We have investigated the problems about multiple criteria decision-making.Using the grey system theory,technique for order preference by similarity to ideal solution,and the vector projection synthetically,a new algorithm of multiple criteria decision-making based on similarity to ideal grey relational projection was put forward.The principle of the algorithm and some basic concepts were introduced.The decision-making model in which the adjacency degree both between the plan and the positive ideal plan and between the plan and the negative ideal plan is taken into account synchronously was set up.And the general steps of decision-making using the algorithm were summarized.Then the method for decision-making sensitivity analysis which bases on the distinguishing degree of the plans was presented.At last,the feasibility and effectiveness of the proposed decision-making algorithm and the sensitivity analysis method were proved by an example.The algorithm which has the high sensitivity level offers a new thought way and more reliable basis for multiple criteria decision-making.关键词：multiple criteria decision-making;ideal solution;grey relational projection;algorithm;sensitivity analysis2|1163|20更新时间：2025-07-16
- 摘要：Exploiting the real-valued property of modulated signals,such as MASK,BPSK,and AM,and employing the received signals of all the array elements and their conjugate datas,virtual spatial smoothing algotithm is proposed by designing virtual subarrays for the highly correlated or coherent case.Virtual subarrays with M identical sensors avoid the reduction of the array effective aperture,and make this approach estimate M-1 coherent signals at most.Finally simulation results show that comparing with forward-backward spatial smoothing algorithm,this algorithm with small snapshots has a better performance and a low computational complexity to some extent.关键词：multipath propagation;spatial smoothing;direction of arrival;array signal processing2|1067|9更新时间：2025-07-16
- 摘要：A forward and backward prediction model with higher accuracy based on radial basis functions(RBF) neural networks was proposed and used to model sea bottom reverberation.The one-step prediction error of the prediction models was used as the statistics for weak echoes detection.The results for envelopes of single-frequency reverberation in lake-trails show that,the defined prediction error of the forward and backward prediction model for that is about 10 lower than that of the forward prediction model,and the prediction error of both prediction models can be used as statistics for the detection of weak echoes in reverberation.关键词：reverberation;RBF neural network;signal detection2|1001|3更新时间：2025-07-16
- 摘要：Using the spatial and spectral correlation within the hyperspectral images,a lossless compression algorithm is presented.Band grouping is used to divide images into different groups.Different hybrid integer transform based on spatial/spectral correlation is taken for each group and to achieve progressive bit-stream,coefficients are reorganized to obtain the same structure as wavelet transformation.Transformation coefficients are then coded by bit-plane-based 3D-SPIHT coding algorithm.Experimental results show that the proposed method can remove the spatial and spectral redundancy more efficiently than JPEG-LS,JPEG2000 and the algorithms based on integer 3D-DCT or 3D-DWT.With band grouping and progressive bit-stream,the proposed method can achieve better error resilient performance.关键词：hyperspectral image;lossless compression;integer transform;coefficient reorganization;3D-SPIHT2|1096|5更新时间：2025-07-16
- 摘要：This paper presents a new acoustic echo canceller combined with the linear predictive speech coders,which includes an adaptive FIR (Finite Impulse Response) filter employing the variable step-size de-correlation NLMS (Normalized Least Mean Square) algorithm and a double-talk detector based on the variance of echo-path mismatch.The simulation results conducted by Matlab demonstrate that the proposed algorithms have better echo cancellation performances compared with the echo cancellation algorithms proposed by Gordy.It detects more correctly in both double-talk and echo-path change,converges faster and achieves an average 15dB higher ERLE and 10dB lower misalignment during convergence.关键词：acoustic echo cancellation (AEC);double-talk detection (DTD);de-correlation;linear predictive4|1634|4更新时间：2025-07-16
- 摘要：For time division polarization measurement,the problem of discrimination and suppression of active-decoys jamming in Polarimetric Synthetic Aperture Radar(PolSAR) is studied.Firstly,the signal models of real targets and active-decoys for PolSAR are presented.Then,their differences in polarization domain are analyzed.Based on their difference of polarization characteristics,a novel method for discrimination and suppression of active-decoys jamming in Doppler domain is proposed.Finally,the scheme of the PolSAR image formation which can remove active-decoys jamming is proposed.Its validity is proved by the simulated experimental results.关键词：PolSAR(Polarimetric Synthetic Aperture Radar);time division polarization measurement;active-decoys;radar image;phase compensation;Doppler domain4|1004|5更新时间：2025-07-16
- 摘要：A scheme of signals with chaotic frequency modulation on the basis of direct digital synthesis technology (DDS) is presented,and the ambiguity characteristic of the signals is analyzed.Based on stochastic process theory,the stochastic characteristic of limited word length chaotic sequences is studied and proper condition of word length for application is obtained.With DDS and chaotic sequence duplicate correlation method,signals of chaotic frequency are generated.The ambiguity characteristic of the signals are researched by the statistic average of wideband ambiguity function,and the anti-interference performance is analyzed.关键词：chaos;DDS(Direct Digital Synthesis);frequency modulation;ambiguity function2|1080|1更新时间：2025-07-16
- 摘要：In direct sequence spread spectrum systems,due to dynamic factors such as the relative motion between the transmitter and the receiver and the instability of clock,there is code-frequency offset between the received and the local PN codes.In this paper,assuming first-order dynamic,namely,constant code-frequency offset,the formulas for the correlation function of PN code are derived for the first time by the method of integrating the normal PN code correlation function with an integration time interval of arbitrary length and then verified by simulation.Accordingly the characteristics of PN code correlation function under first-order dynamic are studied,including spread of main-lobe,shift and loss of peak.The conclusions drawn in this paper can guide the design of code synchronization in high dynamic receiver.关键词：spread spectrum communication;PN code;correlation function;first-order dynamic;code-frequency offset2|1110|9更新时间：2025-07-16
- 摘要：Developing spaceborne SAR-GMTI system is concern by many countries,in view of engineering realize,we presented a spaceborne SAR-GMTI processing system model which use one aperture for transmitter and two receiver,computer simulation results show that the system can suppress clutter effective and enhance signal-to-clutter ratios (SCRs) sharply,so the radar system can easily estimating parameters and detecting ground slowly moving targets even they were embed in clutter.Follow the paper’s method,after processing a part of the actual measured data recorded from an airborne battlefield reconnaissance radar designed by ECRIEE,which take the first airborne SAR-GMTI tested in China,we get a continuous true track of ground slowly moving targets.关键词：spaceborne SAR-GMTI;true imaging track of ground slowly moving targets;clutter suppression;CFAR process2|1042|8更新时间：2025-07-16
- 摘要：A new second generation watermarking method based on DWT was presented in the paper.Based on the model of CBWM,this algorithm applies the visual masking of HVS to the code of watermark.and introduces concept of wavelet block.At first,the algorithm extracts the most important image characteristic value from the coefficients of wavelet transformation as watermark information.And then,it embeds the watermark to decomposing layer of image by modulating.When extracting watermark,the characteristic value is acted as position reference point of watermark.Experiment results show that the watermarking algorithm is robust against common geometry attacks and special anti-interference resistance to rotation.关键词：digital watermarking;DWT;the second generation watermark;HVS;wavelet block;geometry attacks2|1061|3更新时间：2025-07-16
- 摘要：A digital image watermark embedding and extracting algorithm is presented based on the multiscale ridgelet transform (RT) which can efficiently represent image with linear singularities.The RT transform also has directional sensitivity so that among the transformed coefficients the most significant ones represent the most energetic directions of straight edges in an image.To get straight edges the digital image with curvilinear edges or texture is partitioned into small pieces.Then the pieces are treated by RT and the most energetic directions of pieces whose energy are greater than some threshold are selected.And eventually the watermarks are embedded in the the middle ridgelet subband of the selected directions.Different noises with different SNR are added to the watermarked image in the experiments and the results prove robustness and transparency.关键词：image processing;digital watermarking;ridgelet transform;signal extraction2|735|4更新时间：2025-07-16
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