最新刊期
卷 14 ， 期 12 ， 2009
- 摘要：Dual-SAR interferometry shows great potential for detecting the slow ground moving targets.Firstly，according to a performance analysis and comparison of the slow ground moving target detecting algorithms based on interferometry，all the algorithms are divided to three categories.Then，on the basis of analyzing the basic detection theory of each interferometry algorithm，this paper illuminates their advantages and disadvantages.By combining with the simulated results，further analysis and comparison are conducted in terms of detection probability and false alarm probability，the stabilization，the range of detection velocity，anti-jamming.Finally，by summarizing the disadvantages of each interferometry algorithm，this paper indicates the practical use of interferometry for detecting slow ground moving targets.关键词：synthetic aperture radar;interferometry;slow ground moving targets;detection2762|279|0更新时间：2024-05-07
- 摘要：In order to eliminate the graphic aliasing more quickly and efficiently，we propose a sub-pixel level precision regional sampling anti-aliasing algorithm based on integer coordinate，putting sub-pixel information on the low bits and the integral parts on the high bits of plastic number.Calculating the cover area of each pixel with bit operation according to the difference between the sub-pixel part and the integer part.The Brightness level can reach 2n(n is the length of sub-pixel，most of the time it is 8).Compared with mid-point based regional sample algorithm，the picture generated is more precise and fast.Compared with over sampling method(most of the time use 3×3 or 4×4 sample grid)，it’s more precise，when the sample bits arise，the calculation will be the same，and doesn’t exist information losing problems when the data is conversed from high resolution to low resolution witch results aliasing.The result shows our algorithm can quickly generate high quality images better than general antialiasing algorithm.关键词：anti-aliasing;over-sampling;regional sampling;integer coordinate;sub-pixel3521|245|0更新时间：2024-05-07
- 摘要：This paper proposes a nonlocal means filter-based speckle reduction algorithm for synthetic aperture radar (SAR) images.In contrast to traditional methods，the proposed method is capable of discerning pixels of same structural features by exploiting similarity between image patches，leading to efficient reduction of structural information in despeckling.In terms of characteristics of similarity of various structural primitives，a two-stage nonlocal means filtering is used for alleviating the impact of noise on structural similarity measures，and hence improve the despeckling performance.The proposed method has been evaluated on simulated SAR images with varying levels of speckle noise and a real SAR image.Compared to the traditional Lee filter，enhanced Lee filter and the speckle reducing anisotropic diffusion (SRAD)，the proposed method substantially improves the despeckling performance especially on the preservation of structure information.关键词：synthetic aperture radar;speckle noise reduction;structure-preserving filtering;nonlocal means filtering3706|238|0更新时间：2024-05-07
- 摘要：In this paper，the image restoration problem is studied with a given blurred image and a noisy image.We propose a new algorithm combining a TV-L1 de-noising model with a total variational deblurring model.In our algorithm，we use TV-L1 model to de-noise the noisy image in the first； Then we use the TV model to deblur the blurred image by taking the de-noised result obtained in the secod step as the initial value of the next iteration； Finally，they use TV-L1 model again to de-noise the noisy image by taking the de-blurred result got in the second step as the initial value of the next iteration...，and so on.Experimental results tell us that our new algorithm not only inherits the advantage of edge preserving of the TV-L1 model and the TV model，but also overcomes its’ disadvantage of degrading the contrast of image.关键词：blurred image;noisy image;image restoration;altering restoration2829|269|0更新时间：2024-05-07
- 摘要：Inter-mode decision is one of the time-consuming units in H.264 encoder.To reduce the complexity of the block mode decision process，an inter-mode decision algorithm based on spatiotemporal correlation of macro-block was proposed.First，the property of temporal correlation in successive frames and spatial correlation in neighboring macro-block is analyzed，and statistical results for the MB mode change is summarized.According to these characteristics，original candidate modes are chosen.Second，with macro-block tracking of the main macro-block，the most correlated macro-block is found.Then the best coding mode is chosen with a threshold of rate distortion.The results of simulation test show that the proposed fast mode decision strategy can highly improve the efficiency of real time H.264 encoder while maintaining video coding quality.The method can save the encoding time up to 64% on average with －0.31dB performance degradation.关键词：H.264;Inter-mode decision;spatiotemporal correlation;sate distortion optimization;macro-block tracking2738|216|0更新时间：2024-05-07
- 摘要：In this paper we propose a mixture video transcoding method with limited drifting error for H.264 bit rate reduction transcoding.Casacaded pixel-domain architecture is selected to transcode an intra frame and open-loop architecture is selected to transcode the inter frame.At the same time，drift error compensation operation is implemented for the inter frame.Experimental results show that using this video transcoding architecture，the picture quality obtained from the proposed transcoder is close to that of the traditional cascade pixel-domain transcoder，while the transcoding speed is close to the open-loop architecture video transcoder.关键词：transcode;cascade architecture;open-loop architecture;drift error3035|212|0更新时间：2024-05-07
- 摘要：In order to provide the anti-counterfeiting for brand authentication，a fragile watermark algorithm is designed and implemented based on the analysis of the process of cloth manufacturing.In this algorithm，a shortest watermark coding scheme is designed to maintain the temsility balance considering the watermark damage caused by cutting.Experiments show that watermark has no noticeable effect to the appearance，and it is useful for authentication.The method is an effective technical means to authenticate for jacquard brand which greatly increases the cost and difficulties to forge products.It is also an innovation of watermarking technique which can be used in non-digital media texture.关键词：jacquard;digital watermark;fragile watermark;authentication3008|228|0更新时间：2024-05-07
- 摘要：For automatic fetal head measurements and brain abnormalities diagnoses，the detection of fetal skull automatically is needed.So，a method for fetal head skull ellipse detection in ultrasound image is proposed.The main process is as follow: firstly the K-mean algorithm is used to cluster pixels into 3 classes and the bright objects are identified； then only the bigger connected components in the bright objects are preserved and skeletonized； finally randomized Hough transform (RHT) is applied to skeletonized components for ellipse detection.The adopted preprocessing method greatly reduces the number of pixels to be examined by RHT and improves the detection speed.Furthermore，a new scoring mechanism for RHT is introduced，which takes into account the head curves performance in both image and parameter spaces and increases detection accuracy.关键词：ultrasound image;fetal head;ellipse detection;Hough transform3145|244|0更新时间：2024-05-07
- 摘要：Aimed to reduce the influence of car shadows on video detecting，this paper researched into the invariance of HSV color model which was often used in shadow detection，and pointed out that the invariance of hue and saturation before and after shadow casting is not always satisfied on the road area，and exemplified the limitations of the method caused by the singularity of the hue transform.Then an improved algorithm based on the invariance of the ratio of two different color variant values was presented which is more suitable for road environment.Experimental results show that the developed algorithm can distinguish the car and its shadow better and help to extract accurate traffic information.关键词：ITS;shadow detection;HSV;invariant color model;singularity3270|231|0更新时间：2024-05-07
- 摘要：In order to realize high-speed motion detection and camera ego-motion estimation in image processing，an insect-inspired Reichardt motion detector (Elementary Motion Detector (EMD)) and receptive fields based on insects vision system are applied.The principal characteristics and drawbacks of the Reichardt model are analyzed.According to one of its main drawbacks，a modified model is selected which performs better in motion detection than the original method.Moreover，six templates of receptive field based on flys vision system are designed for simple ego-motion estimation，such as self-translation and self-rotation of the camera.Finally，the related algorithms are implemented on a FPGA (Field Programmable Gate Array) platform.The results of several typical experiments demonstrate，that the EMDs can detect local optical flow quickly and the receptive field templates enable simple motion estimation under specific backgrounds.The developed FPGA system is sufficient to deal with a video frame rate of 350 fps at 256×256 pixels resolution，the resulting time delay of the Reichardt model implementation is only 0.25 μs.This hardware can be applied to real-time computer vision systems，such as for obstacle detection，motion estimation，UAV/MAV’s stability control and so on.关键词：computer vision;Reichardt motion detector;receptive field;motion estimation;FPGA3459|239|0更新时间：2024-05-07
- 摘要：Fast and accurate estimation of global motion is necessary in target tracking，video coding and etc.Considering the global motion estimation of video with both camera motion and foreground objects motion，a new global motion estimation algorithm is proposed.In the algorithm a three-level pyramid is utilized.Then outliers are effectively eliminated with the block-based methods in the calculation of each pyramid level.In order to accelerate the algorithm，4-Queen and 8-Queen patterns are also used to sample background pixels respectively on the intermediate level and the base level，and only the extracted pixels are contributed to the iterative calculation.The experimental results show that the algorithm improved the estimation speed greatly without reducing the accuracy and satisfied the real-time request.关键词：global motion estimation;subsampling pattern;iterative algorithm;motion model3131|198|0更新时间：2024-05-07
- 摘要：In order to carry on the gait recognition fast and effectively，aiming at the characteristics that gait energy image can view the information of gait and two dimension principal component analysis can reduce the dimensions quickly，a novel gait recognition based on gait energy image and two dimension principal component analysis is proposed in this paper.Firstly，the body silhouette extraction is achieved by background subtraction.Secondly，a gait cycle is obtained with the correlated signal of the ratio of width and height of human body.Gait energy image is applied on the binary image sequence to construct the feature vector.Finally，(2D)2PCA and W(2D)2PCA is used to reduce into a low dimension space.The nearest-neighbor classifier is adopted to distinguish the difference.This gait recognition method can decrease the influence of the early preprocess effectively，and our experimental results demonstrate that the method is effective and has achieved a good recognition effect on CASIA gait database including three different multi-views.关键词：gait recognition;gait energy image;two dimensional principal component analysis;(2D)2PCA;W (2D)2PCA3631|254|0更新时间：2024-05-07
- 摘要：According to the problem of vision based localization for the outdoor patrol robot，an approach of road crossing scene recognition based on scale invariant feature transform(SIFT) and color features is proposed in this paper.Firstly，the SIFT features are extracted and the color histogram in HSI space is calculated.Secondly，the K-D trees algorithm is used to match SIFT features of images in road crossing images database，and the Bhattacharyya distance match result is calculated using color histogram.Finally，the SIFT features match result and the Bhattacharyya distance match result are combined together to confirm the suitable image in database.The image pre-classified idea is also adopted to accelerate the SIFT features matching.The experiment results demonstrate that the algorithm is robust to the various illumination，dynamic disturbance and self-circumrotating，and can be used for robot location.关键词：Scale invariant feature transform (SIFT);color histogram;clustering;Bhattacharyya distance3279|218|0更新时间：2024-05-07
- 摘要：To address the License Plates (LP) extraction in complex natural environments，a novel approach to LP extraction was presented，which utilized LP’s color information，gray feature and geometry characteristics.Firstly，a color classification method was proposed based on the distance between different colors according to the Chinese car license plate color features.Secondly，LP’s background color zones were segmented by scanning lines of picture and analyzing the line segments.Finally，these Zones were translated into binary image in which LP’s background color was dark and LP’s foreground color was white，and validated by the LP’s gray features.In a certain degree，the method could adapt to LP’s type，size，number and direction and wasn’t limited to the location of car the and the background in the picture.It was tested using the natural pictures，and was approved to be effective and adaptive.关键词：license plate extraction;color classification;color features3095|464|0更新时间：2024-05-07
- 摘要：Watershed transform is the main tool of mathematical morphology used for image segmentation which can produce one-pixel wide and close edge.This method applied directly to gradient image causes severe over-segmentation.In this paper，the author presents a multi-scale watershed transform based on morphological scale-space by the analysis to the reasons of over-segmentation produced by watershed and the possible under-segmentation due to watershed-plus-marker.The method proposed here could be divided into three steps: (1)The alternate sequential filters(ASF) based on reconstruction are used to reduce some difference inside objects； (2)The closing by reconstruction be applied to gradient image in order to remove some local minima that does not correspond to the maximum and the minimum of the original image； (3)The processed gradient image is segmented using the watershed transform.关键词：reconstruction;alternate sequential filters;watershed transform3277|267|0更新时间：2024-05-07
- 摘要：A new image segmentation algorithm using level set method was presented，which is based on the gradient vector field flux fitting energy.Combing with the penalizing energy term of signed distance function and minimizing the energy functional，we obtain the variational formulation which has four main advantages over the traditional active contour models.First，the difficulty of segmentation with weak edge can be addressed.Second，the level set function allows for flexible initialization and needs no re-initialization during evolution.Third，the level set function can be easily implemented by simple finite difference scheme and is computationally more efficient.Fourth，the interior contour of object can be automatically detected with only one initial contour.The proposed algorithm has been applied to both synthetic and real images with promising results and the results of segmenting weak edge objects and images with intensity inhomogeneity are better than using either geodesic active contour (CAC) model or C-V active contour model，respectively.3331|188|0更新时间：2024-05-07
- 摘要：In this paper we proposed a MFA based RSOTP subspace learning method.By employing stable discriminant vector in initialization and using an alternative orthogonal selection and throwing off weight matrix，this approach enhances the robustness of the learning process and strengthens the classification ability，and achieves better recognition performance on both large and small face datasets than conventional techniques.关键词：tensor projection;subspace learning;face recognition3068|205|0更新时间：2024-05-07
- 摘要：Density-guided tree-structured kernel is proposed for the situation that the learning algorithm is not fit well for instances consisting of unordered feature sets with unequal cardinality.The feature set is automatically decomposed into a tree，and two feature sets are embedded into this tree to form two multi-resolution histograms，and then the histogram intersection，weighted by the density of feature points in common nodes from two multi-resolution histograms，is computed.The partial correspondences between feature sets can be determined automatically through this kernel，its computation is linear with the number of features，and it is positive-define.This kernel is embedded into kernel based discriminative classifier for image object classification，and compared with vocabulary-guided pyramid match kernel.The experiments show that the density-guided tree-structured kernel can obtain the better classification performance.关键词：feature sets;tree structure;partial matching;support vector machine2788|211|0更新时间：2024-05-07
- 摘要：As for low resolution of remote sensing images，a novel fuzzy reasoning fusion algorithm by nonsubsampled contourlet transform was proposed.Firstly，the multi-spectral image is converted from RGB space to IHS space through IHS transform.Next，with nonsubsampled contourlet transform and weighted average fusion rules based on fuzzy reasoning，the component intensity and panchromatic image are merged into a grayscale image.Finally，the stretched grayscale fused image replaces the original component intensity，and then the final fused image is achieved by inverse IHS transform.The experimental results show that the proposed method not only can obtain better effect on restraining spectral information distortion and enhancing space definition than other multi-resolution analysis methods，but also avoid some of the well-known problems in common fusion processes such as blurring effects and high sensitivity to noise.关键词：remote sensing image fusion;nonsubsampled Contourlet transform(NSCT);IHS transform;fuzzy reasoning2777|257|0更新时间：2024-05-07
- 摘要：A rectification approach for catadioptric omnidirectional image pair via the rectification of corresponding unwarping cylindrical image is proposed.The acquisition and unwarping process of omnidirectional image is discussed firstly.Then，according to imaging principle of cylindrical panoramic image，corresponding epipolar geometry and solving is analyzed.Meanwhile this paper develops an criteria for resampling-effect assessment depending on the degree of pixel information exploitation that rectified images based on the reference images.And it shows that，under this criterion，rectification for cylindrical image by resampling reference images along epilines has obvious advantage in terms of pixel-maintain-rate and effective-pixel-rate compared to other approaches.To reduce resolution degradation and image deformation resulted from proposed rectification algorithm，issue of how to sampling reference images maximum as much as possible according to the epipolar geometry is mainly studied and solved.Lastly results of our approach applied to both synthetic and real scenes are given at the end of this paper.关键词：catadioptric omni-directional image;cylindrical panoramic image;epiline-sampling;image rectification;epipolar geometry3204|245|0更新时间：2024-05-07
- 摘要：Demons algorithm is an intensity-based fully automatic deformable image registration method.Its result is liable to be affected by the inconsistency of the intensity between the images，and its iterative convergence process is relatively slow.In this paper，a novel pretreatment approach of intensity normalization based on polynomial least squares fitting has been implemented to match the intensity between the images，and an accelerating algorithm for adaptively adjusting the deformation force of the floating image during the iterative process has been designed to speed up the process of convergence.This improved algorithm，the original algorithm and other improved algorithms have been applied to mammogram registration，and the results of the comparison show that the new method can obtain more accurate results with faster speed.The registered image which enhances genuine alterations in breast tissue would benefit the early detection of breast cancer.关键词：non-rigid registration;intensity normalization;medical image;mammogram;demons algorithm3038|185|0更新时间：2024-05-07
- 摘要：This paper presents a Multi-scale feature extraction algorithm，which computes the maximum of the features in moving windows using fast algorithm reduces the search redundancy and obtains the matching features using the nearest neighbor matching algorithm .The experimental results show that this algorithm is faster than the SIFT and MOPS，and has more stability than Harris algorithm.The algorithm can be used in image registration and target tracking.关键词：feature extraction;feature matching;multi-scale transform;multi-scale oriented patches（MOPS）;scale-invariant feature transform(SIFT);Harris corner4219|255|0更新时间：2024-05-07
- 摘要：Contour filling is based on the topology relationship between contours，which remains a difficult research question.In order to fill contours fast and conveniently，a new automatic filling algorithm between contours based on triangulation irregular net was proposed.From the relationship between unclosed counters generated by the irregular triangulation net and the custom border，the closed counters were built，and then the filling color between contours was determined through determining the relationship of the closed counters，so the contour filling chart was mapped.This algorithm is easy to implement and the computing speed can meet the business needs.关键词：triangulation net;contour;filling3446|228|0更新时间：2024-05-07
- 摘要：Topology analysis of spatial data model is a very important step in geological modeling.To construct coherent geological blocks，we should analyze the topology of all elements in the surface model.When the scale of surface model is very large，this global analysis must be limited by memory capacity.In order to improve the speed of computation，this paper presents an algorithm of constructing geological blocks which is based on the simplified surface pieces.This algorithm simplifies the data of surface model as much as possible and only preserves crucial data which have relation with the intersection lines.Such simplified surface model has global topology information and can be read wholly into memory.Experimental results show that，this algorithm can effectively speed up the process of topology analysis，and can be applied to geological model with large-scale data.关键词：triangle mesh;coherent blocks;surface piece;geological modeling3488|161|0更新时间：2024-05-07
- 摘要：To model smooth surfaces representing tree branches by using implicit surfaces to improve the diversity of computer generated tree branch surfaces，and to bring realistic description of its local details，a method is proposed to model 3D tree surfaces.This method combines implicit surfaces based on skeletons and convolution surfaces based on line segment primitive with polynomial density distribution.The BlobTree provides several techniques to control the combination of primitives.Better blending is used to remove the blending bulges.It is showed that smooth blends can be obtained without noticeable bulging.PCM (precise contact modeling) is used to model local details on the face of trunk and branch of the tree.The appearance of the generated tree model is improved by using color filling，while the used colors are selected from the real tree branch image according to a probability distribution.Experimental results demonstrate that the proposed method can reconstruct various smooth 3D tree branches with local detail features such as branch bark ridges and tree bulges.关键词：implicit surfaces;convolution surfaces;modeling 3D tree;surfaces modeling;realistic rendering3282|270|0更新时间：2024-05-07
- 摘要：Aiming at some defect in pixel domain and the MPEG compressed domain for shot boundary detection，making full use of new characteristics of the H.264/AVC video coding standard，in this paper，we present a shot boundary detection method based on the H.264/AVC compressed domain.Firstly，the frame should be decomposed into 4×4 blocks，and then the difference information between the corresponding blocks in the intra-prediction mode or the inter-prediction mode is counted up.At last，the shot boundary detection is accomplished for different types of video by using adaptive threshold decision.Experimental results show that the proposed method achieves satisfactory performance of recall and precision.关键词：H.264/AVC;shot boundary detection;prediction mode;adaptive threshold2922|201|0更新时间：2024-05-07
- 摘要：To assess images applied with JPEG double compressed，the DCT statistic of the JPEG image will be changed，which is the focus in this paper.The distributions of DCT coefficients are varied with the double compression quantization tables: q1，q2.The difference of the distributions is analyzed in this paper.The different detection methods are proposed based on different q1，q2，which are effective proved by the experiments in this paper.关键词：JPEG double compressed;periodic mode;histogram3033|201|0更新时间：2024-05-07
- 摘要：Feature extraction and classification is very important in the iris recognition.The low frequency sub-image of the wavelet transform contains the primary information of the iris，and the Log-Gabor filter can effectively extract the iris texture information.The combination of these two approaches is an effective way to extract the iris texture.This paper firstly decomposes the normalized iris image by the wavelet transformation to obtain the sub-images，and then uses a Log-Gabor filter to extract the features of the low frequency sub-image and generates the iris code.Finally support vector machines (SVM) is used to classify.The experiments results show the SVM can achieve good effect on the iris classification.The recognition rate is up to 99.6% and the equal error rate is reduced to 0.3%.Compared with the hamming distance，the SVM has the better performance.关键词：iris recognition;wavelet transform;Log-Gabor filter;SVM2824|321|0更新时间：2024-05-07
- 摘要：This paper regards the three components of color image as a pure quaternion and presents the algorithms for color image zooming via spherical linear quaternion interpolation and algebraic trigonometric blending quaternion interpolation spline based on the research of the intrinsic correlation of color components and the nonlinear mechanism of image itself.Illustration shows that，using the new quaternion interpolation method，the clarity，brightness and more rich details on the edges of color image have greater improvements than the cases of traditional method by bicubic spline interpolation.关键词：quaternion;color image interpolation;spherical linear interpolation;algebraic trigonometric blending spline interpolation3476|231|0更新时间：2024-05-07
- 摘要：A novel multiple face tracking algorithm is proposed in this paper.Multiple Mean Shift trackers are first built to enable multiple face tracking.To overcome the weakness of Mean Shift tracking，which is prone to converge to the local maximum target if tracked objects are adjacent or partially occluded，a greedy tracking method is used to pursue the targets one by one，during which a Kalman filter is first employed to locate the initial position，and then the tracked object is removed from the scene to guarantee no other Mean Shift tracker iterates the same target.An accessory window featured with local texture distribution is introduced to correspond to candidate widows and targets.Experimental results have indicated the proposed algorithm can track multiple faces robustly in real time.关键词：Face tracking;multiple target tracking;mean shift;greedy algorithm3331|225|0更新时间：2024-05-07
- 摘要：According to the framework of procedure recovery in feature-based data exchange，this paper discusses the key issues of feature extraction and reconstruction，including the extraction of first-order feature information，extraction of second-order feature information and the reconstruction of feature model.The proposed methods have been tested in experiments.The result shows that the approach has efficiently improved the former methods.关键词：feature model;data exchange;collaborative design2998|225|0更新时间：2024-05-07
- 摘要：It is a challenging work to design a robust audio watermarking scheme against desynchronization attacks.In this paper，a feature-based digital audio watermarking scheme robust against desynchronization attacks is proposed.Firstly，the steady feature points are extracted from the host audio according to the local energy distribution.Then，the candidate audio segments for embedding watermark are defined by using the feature points.Finally，the digital watermark is embedded into a host audio by modulating the statistics average value of audio samples.In digital watermark detection，the feature points are selected by the same technique as the embedding，and the digital watermark is extracted from the watermarked audio after the feature points.Experimental results show that the proposed scheme is inaudible and robust against common signals processing such as MP3 compression，low-pass filtering，noise addition，and equalization etc，and is robust against desynchronization attacks such as random cropping，amplitude variation，time-scale modification，and jittering etc.关键词：audio watermarking;desynchronization attack;feature point;local energy2826|211|0更新时间：2024-05-07
- 摘要：The information source has been a bottleneck problem which troubles the vehicle digitalization process for a long time.With the rapid growth and wide range of adoption of Radio Frequency Identification (RFID for short) technology，a new viable solution is provided to solve the problem.With the adoption of RFID technology，the information security problems can be solved.This paper discussed the characteristics and peculiarity of RFID technology as vehicle digital standard info-source (VDSI for short)，and proposed a VDSI database encrypting engine.关键词：RFID;VDSI system;information security;database encrypting engine3349|263|0更新时间：2024-05-07
- 摘要：With the rapid development of smart surveillance technology，more and more surveillance systems in public environments by humans have turned to be assisted by intelligent video surveillance system.To resolve the problem of background modeling initialization and updating in outdoor surveillance videos，an adaptive background modeling method is proposed.An intelligent surveillance system for transportation is also developed.Experimental results demonstrate the effectiveness and efficiency of the system.关键词：video surveillance;adaptive background modeling;transportation surveillance;intelligent vehicle suiveillance3423|219|0更新时间：2024-05-07
- 摘要：A novel video watermarking scheme based on motion vectors and DCT coefficients is proposed in this paper.In the field of video watermarking scheme based on compressed domain，the scheme based motion vectors and the scheme based on DCT coefficients have become a hot research topic，but there are both advantages and disadvantages in each scheme.So a hybrid video watermarking scheme based on motion vectors and DCT coefficients is proposed.The watermark is embedded in motion vectors and DCT coefficients of the video sequence.And the two kinds of watermark can be corrected for each other.Experiments indicate that after embedding the watermark，both the objective video quality and the subjective video quality are the same as that of original video sequence and the increasing of bitrates is controlled in 1%.关键词：hybrid video watermark;H.264;digital watermarking;motion vectors;DCT2830|251|0更新时间：2024-05-07
- 摘要：This paper proposed a novel robust oblivious watermarking scheme in the spatial domain suitable for 3D mesh object，which combines the principal component analysis (PCA) method with construction of cone bins.Firstly，PCA is used to calculate the eigenvectors of covariance matrix of vertex coordinates.Then the object is rotated and translated so that its center of mass and the three eigenvectors that coincide with the origin and the three axes of the Cartesian coordinate system.Subsequently，many cone bins are constructed，each bin center according to two angle parameters of spherical coordinate produced by pseudorandom number generators and the vertices are classified into the appropriate cone bins.Each cone bin is divided into a number of sub-bins in order to embed the watermark bit，and the size of sub-bin can make tradeoff between invisible and robustness.Experiment results show the remarkable ability of the proposed mechanism to resist against various attacks such as adding noise，clipping，similarity transform and vertex re-ordering.关键词：watermarking;3D model;PCA;robustness2970|203|0更新时间：2024-05-07
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