最新刊期
卷 9 ， 期 7 ， 2004
- 摘要：This paper presents a survey on the field of Augmented reality(AR), which combines virtual computer generated material with the surrounding physical world, registers real and virtual object with each other and runs interactively at real time. Now it has become an important research field in VR and next generation of human computer interface. This paper introduces the primary content and state of art in this field. The key technologies, including basic tracking methods, display devices and registration processes, are discussed. Many typical AR applications and developing tools are listed. It describes the characteristic of AR system, with a detail analyzing of some technology difficult problems in AR system. The corresponding solutions are also mentioned. Currently research in AR field is largely focus on the AR system frameworks. Which usually gives a unified interface that supporting heterogeneous AR display devices in different AR applications. The AR frameworks also make the design of AR applications become more convenient. Two most influential AR frameworks, Studierstube and DWARF, are introduced. This survey provides a start point for anyone interested in AR research.12214|374|0更新时间：2024-05-07
- 摘要：Deformable template matching is a kind of useful method for contour extraction and image segmentation in the fields of computer vision and image analysis. In this paper, by utilizing the gradient trajectories of a two dimensional function, a novel analytical form based two dimensional parametric deformable template with three kinds of biological tissue bone, muscle and skin is built, which has more reasonable template structure used to control the template deformation. In order to improve the operational efficiency of the new matching method, a heterogeneous discretization scheme is adopted. Then the new definitions of similarity internal energy function, smoothness internal energy function and external energy function are presented to reduce the sensitivity to initial placement of the template. Gaussian function is used to widen the capturing scope of the external force in the external energy function definition. Finally, greedy optimization fast algorithm is used to obtain globally optimal solution with more acceptable complexity of computation than dynamic programming. The experimental results on real images show that our new matching method is efficient and robust to accurate contour extraction.3335|242|0更新时间：2024-05-07
- 摘要：A new approach aimed at the registration of three-dimensional(3-D) coronarographic images is reported. The matching of 3-D vessel central lines is performed using attributed string matching techniques. Firstly, we extend the 2-D Freeman chain code to 3-D space. We then give a brief description of string matching techniques, with a special emphasis on image analysis. Some key elements involved in the algorithm such as chain encoding, cost function, normalized edit distance are proposed and discussed. In this paper, two types of substitution cost functions are introduced and used in string matching algorithm. Their performances are compared on experimental data obtained and further evaluate the results by means of subjective and objective criteria. The experimental results show that the use of the second substitution cost function can yield better matching results.2867|216|0更新时间：2024-05-07
- 摘要：The isotropic diffusion method for image denoising such as those based on the Laplace regularization can smooth out the noise in image, but it may simultaneously blur the edge or boundary of the objects. In order to overcome this problem, recently many researchers pay attention to the smooth method based on the total variation (TV) regularization because it can reserve or even enhance the information of edge when smoothing the noise. However, since equation system deduced by TV method is a strongly nonlinear system, the convergence rate is very slow when solving TV equations using relaxation method. So in this paper, we introduce the multi-grid algorithm and conjugate gradient (CG) algorithm to solve this system. By smoothing out the noise in the echocardiograpgic images, numerical results indicate that the convergence rate of CG is fast, the algorithm of multi-grid has more efficiency and the image can be recovered with satisfied result even contamination of strong noise. As a result, the multi-grid algorithm is a good alternative method for solving the TV questions.2645|211|0更新时间：2024-05-07
- 摘要：Bubbles extraction in the images of aerated water flows accurately is the precondition to analyze the characteristics of water flows by image detection. Because bubbles are colorless and transparent in the aerated water flows and the contrast of object and background is too low and at the same time there are un-even illuminations during experimentation. It is difficult to segment bubbles accurately. In order to solve the problems of miss-extraction or deformity of bubbles which caused by un-uniformity of bubbles resulted from the un-balance illumination of the image, a method based on two layer dynamic thresholding is proposed in this paper. At first, the local areas which containing bubbles are obtained dynamically by labeling in the first layer processing. Then, bubbles are extracted accurately in the second layer with fine segmentation based on the labeled bubbles' area in the first layer. Experimental results show that the proposed method is very efficient in solving the bad illumination and can highly improve the accuracy of bubble extraction.2433|208|0更新时间：2024-05-07
- 摘要：This paper will resolve shape identify from a new position. In course of image processing, the pixels are endowed with electric quantity. Every shape of image is indicated by electric field strength and electric potential in 3-D space around the image. In this paper, the processing is based on binary image. Firstly, edge of the image is got by edge detection techniques and then corner points by polygonal approximation. Lastly, electric field strength and electric potential are calculated for normalizing observation points. The calculated value will indicate different images. It exists infinite observation points for one image. Therefore it's important and necessary to choose appropriate observation points in practice. Because they indicate the shape information more reasonably and fit computer for judging. The algorithm derives from physics and easily be understood in physics. The paper give necessary deduction and experiments, when the images are revolved,moved and distorted ,the method also could show a better result in recognition. The key of following work is to resolve how to choose observation points, so that recognition result will be more precise and robust and can be competent for complex images.关键词：electric potential;electric field strength;polygonal approximation;normalizing;shape identify;observation point2509|208|0更新时间：2024-05-07
- 摘要：As we all know, Shape description is a central problem in pattern recognition. However, most simple algorithms for generating 2D shape descriptors, whether they are based on boundary features or regional features, can only be used in certain applications or have deficiencies in some performances. To address such problem, based on the coordinate relationship between the current boundary pixel and its two lockstep boundary pixels, a general-purpose method ( so called region histogram ) for region shape representing and describing is presented in this paper. Region histogram is the sequenced horizontal intervals along the region boundary in accordance with some classification and calculation criterion , which actually represent the region's area and its boundary length in terms of pixels. In order to quantify the recognition ability of the region histogram method and compare it with the analogous ones, a series of tests were carried out using a set of standard shapes, which have been proposed by Rosen and Gleason, comprising of a disc, a square, a rectangle and an equilateral. The results show that region histogram method is robust and effective to region shape representing and describing; even it does better with complex regions which have much more global and local contour information. Therefore, this method presents a new effective way for shape representing and describing, and can be used in pattern recognition such as robot vision applications.2505|207|0更新时间：2024-05-07
- 摘要：In this paper, 3D pulse-echo imaging with limited diffraction array beams is presented. Because only one transmission is required to construct 3D images, and the entire transducer aperture is used and both the transmission and reception beams do not diverge over a large depth of interest. The images obtained with limited diffraction array beams have a higher SNR and high frame rate compared to images obtained with conventional focused beams. Data acquired is transformed into spatial scattered data by normalizing. A new algorithm of surface construction is proposed. An assistant surface is constructed on the base of boundary that being automatically extracted from the scattered data. In the aggregate of rectangle fields of data, the assistant surface is modified to get the final surface by a piecewise bicubic Hermite interpolation. In the experiment, computer simulation of the imaging method with limited diffraction array beams has been carried out. A plane wave is used. At the same time, a single surface is reconstructed with the new reconstruction method described in this paper. However, to confirm validity a sphere and a face data acquired by laser are used to reconstruct. Results show that the algorithm has run short time, good fairness, without triangulation.3198|182|0更新时间：2024-05-07
- 摘要：In acquiring image, due to the relative motion between an imaging system and its objects, the every value of grey scale of pixels expresses several ones within area instead of itself one pixel. It, thereby, results in imaging degrading, and engenders blurring imaging. The paper analyses a real process about image blurred as a result of object motion, reveals an intrinsical cause about image-degraded owing to object motion, and establishes blurring-model by which one dimension and two dimensions uniform velocity rectilinear motion result in image blurred abide. Based on result of blurring imaging pixel motion, the writers introduce a restoring model of blurring imaging from reverse process of degrading-process and conclude a restoring technique of motion blurring imaging from it. As an instance, the paper models a blurring process for uniform velocity rectilinear motion and restores it again. The example conforms the technique is available, especially for restoring characters and texts. A special discuss on boundary pixel problem is given. An analyse about error cause in process of restoring is introduced. In the end, the method's advantage and disadvantage and how to improve on it were discussed.关键词：pixel motion;degrading cause;blurring model;restoring model;single dimension motion;two dimension motion3386|161|0更新时间：2024-05-07
- 摘要：The color histogram based image retrieval method is simple and invariant for translation and rotation of the images but losing the spatial information of the color. Recentlymanymethods, such as accumulative histogram, color correlograms, local color histogram, etc, are introduced to improve the color histogrammethod. In this paper, a new content-based color image retrieval method is proposed, in which both the color content and the shape feature of the image have been taken into account. Firstly, based on the special disposal on the HSV color space, an improved accumulative histogram of the hue is calculated as the color feature. To attain the spatial information, H-, S-, and V-component of the image are firstly divided inton×nblocks which are classified into 3 status, flatness, texture and edge status. Then each gray image is translated into a matrix composed of those 3 status values. After that the status matrix is transformed into 1-dimension status sequence, the transition probability matrix of the sequence is calculated as the image’s spatial distribution information. In matching the similarity of the images, the Guassian model is used to normalize the different sub-characters distance. Experiments with different kinds of images indicate that this method is great effective in image’s retrieval.3091|214|0更新时间：2024-05-07
- 摘要：Evaluation of definition for gray scale digital image is an important aspect of digital imaging system. Thus, in order to evaluate the definition of a gray scale image accurately and effectively, we present a new approach based on EVA method which, while retaining important features of existing method, overcomes some of their limitation. With curvilinear regression analysis we can prove that the result of the new approach is high correlation with MTF measured by optical instrument, in other words, the new method is sensitive to the change of image definition. When compared with traditional method, the result of analysis can also show that the new method is better than traditional method, such as entropy, to assess gray scale digital image definition. Experiments using hundreds of many kinds of gray scale digital image and the result of this new approach is well accurate to the change of definition of digital image. Form these we can also draw a conclusion that the new approach can be well applied to many kinds of gray scale digital image accurately and effectively.5040|304|0更新时间：2024-05-07
- 摘要：Spatial overlay analysis is an important problem of spatial data analysis. Sometimes spatial data are fuzzy in Geography Information Systems and spatial database, so fuzzy overlay analysis has gained more and more attention from researchers during the recent years. Based on the interval value character of the attributes in GIS applications, the fuzzy map layers of fuzzy attribute data were described as interval valued fuzzy sets. Then an overlay analysis model of fuzzy raster map layers is proposed based on interval valued fuzzy sets. It improves the original fuzzy overlay analysis model, which based on classical fuzzy sets. With the basic operations of interval valued fuzzy sets the model can complete general fuzzy overlay and weighted fuzzy overlay. The weighted fuzzy overlay model will degenerate to general fuzzy overlay when the weights of fuzzy map layers are equal. The fuzzy overlay model can reduce the losing of attribute fuzziness through using interval value to represent the fuzziness, and the fuzzy overlay result accord with the cognitive and reasoning principle of people. The result of the instance shows that this model can well solve fuzzy overlay analysis between the map layers of interval value attributes.2912|193|0更新时间：2024-05-07
- 摘要：Wavelet analysis is chiefly due to the‘adaptive feature’and‘mathematical microtelescope feature’. The 2-D continuous wavelet transform (CWT) is a powerful new tool and has been applied to a number of problems such as astrophysics, aeromagnetic processing, seismic and gravity. It is also used in remote sensing image analysis. This paper focuses on multi-scale analysis at NOAA/AVHRRthermal data (Channels 4 when present). The approach is using an isotropic 2DMexican hatwavelet(DOG m=2), and studied each componentwithmulti-scale matched onmulti-date data againstthe distributionmap of land-cover classification, which is made up to each pixel on NOAA/AVHRR image withTM image supported, to reveal 2D signals in the temporal variation and spatial patterns. In aword, the result shows the information abouttype of land cover classification and relation, location, and shape in its in small scale as micro-scale analysis and emphasize terraqueous variance by physiognomy, the strengths and features of its trend and structure in large scale as macro-scale observer. The variance of coefficient of different land cover types and the zero-crossing variance of coefficient with scale in 2D CWT discovers the power of signal and the correlation.2167|211|0更新时间：2024-05-07
- 摘要：It is very important to compress vector relief data for the study and application of the terrain environment simulation, cartographic generalization, GIS and so on. Using the theory of wavelet analysis and the characteristics of the vector relief data, in this paper, a model to compress contour data is developed. Firstly, a basic ideal is proposed to compress contour data based on wavelet transformation. Then, the boundary of wavelet transformation is processed by a developed method. And the feature points of contour data are selected according on given rules so that the compressed data can retain the characteristic of original data well. Thus, a model to compress contour data is obtained based on wavelet transformation. Finally, actual contour data are experimented using the developed compression model. The theory analysis and experiments show that the developed model not only obtains the high compression ratio for contour data but also retain the trend and the characteristics of original contour data. The developed method can be used with the widely areas such as digital terrain models, GIS, remote sensing et al.2932|490|0更新时间：2024-05-07
- 摘要：Zhengyou Zhang has proposed a Two-Stages camera calibration method by viewing a plane recently. It can calibrate camera easilywith high accuracy and is considered as a presentation of Two-Stages method. But only radial distortion is considered in his camera model, and when the tangential distortion is distinct in some lenses, such as in fish-eye lenses, the camera model will be unsuitable. Therefor his camera model is improved in this paper and an improvedTwo-stages method is proposed. Through the proposed method the initial parameters are solved by using the points near the image plane center. As the distortion is very litter nearthe image plane center, the solved initial parameters can be very close to exact ones, then, a subspace trust regionmethod based on the interior-reflective Newton method is applied to solve all the camera parameters accurately. Both computer simulation and real data have been used to test the proposed technique and very good results have been obtained. Compared with Zhang’s method, the proposed method is more accurate and it works better robustness.3059|214|0更新时间：2024-05-07
- 摘要：Guidance using path following iswidely applied in the field of autonomousmobile robots. Comparedwiththe navigation system without vision, visual navigation has obvious advantages as rich information, low cost, quietness, innocuity, etc. This paper describes a navigation system which uses the visual information provided by guide lines and color signs. In our approach, the visual navigation is composed of three main modules: image-preprocessing, path-recognition and path-tracking. First, image-pre-processing module formulates color models of all kinds of objects, and establishes each object’s support through adaptive subsampling-based binarization and mathematical morphology. Second, path-recognition module detects the guide lines through an improved Hough transform algorithm, and the detected results including guide lines and color signs integrate the path information. Finally, calling different functions according to the movement of straight-going orturning, path-trackingmodule provides required input parameters tomotor controller and steering controller. The experimental results demonstrate the effectiveness and the robustness of our approach.4262|265|0更新时间：2024-05-07
- 摘要：In the paper,a road edge identification algorithm is developed .The new idea of this method is touse natural road edge ,as well as the whites trip for road information acquisition .Then atural roade dge will notbee as ilypolluted like the white lane maker do ,soitindicates bettera daptability .Inthealgorithm ,weuseboth the pixelfeature and the framefeaturetoidentify theroadedge ,which is referred to as the global road model.Be cause several road constrainsisused toensure the roadedgede tection ,the algorith misimmune to the influence of thei magedistur bance .The algorithm of theroaded geidentifi cationin cludes two stages:initializationdetection and tracing detection .The in itialization stagedetects the roadedge from the global roadimage . The tracealgorith muses there gion of interest (ROI)to limitdete ctingarea ,which can save muchtime .Inorder to giveamea sure of there liability of the road detecting result,this paper presents a road edge identification esti mation function ,which canesti mate the reliability of the road edge .2734|257|0更新时间：2024-05-07
- 摘要：An adaptive multi-dimensional discrete cosine transform (multi-D DCT) algorithm are proposed in order to obtain high compression for still color image under high signal-to-noise ratio. In this algorithm, the original image is splitted into non-over-lapped 8х8 blocks. Then the statistic characteristic of each block is calculated and assess the abundance of inner information in each block based on averages and variances. To the block of which the inner information is abundant, correlations between adjacent pixels of each block and YUV channels of color space are exploited through 3-dimensional discrete cosine transform(3-DDCT);To the block ofwhich the inner information is not, correlations among adjacent pixels of each block ,YUV channels of color space and adjacent blocks are exploited through 4-dimensional discrete cosine transform(4-D DCT). The transform coefficients are coded by quantization further. Experimental results have proved that the proposed algorithm can achieve higher compression ratio and ThePSNR(average Peak Signal-Noise-Ratio) of reconstructed image is higher than by JPEG.2933|139|0更新时间：2024-05-07
- 摘要：Transmitting video streaming over Internet is a challenging problem because the bandwidth of network varies all the time. Scalable coding seems to be an effective solution to resolve the bandwidth varying on the streaming video application over Internet. Though traditional scalable video coding schemes get scalability, the scalability is coarse and need much more memory expense. To obtain fine granularity scalability, the MPEG-4 video coding standard adopts FGS coding scheme. It permits bitstreams after being coded be truncated and transmitted arbitrarily with the available bandwidth. However, the fine granularity scalability of the FGS is obtained at sacrifice of coding efficiency. The reason that causes the FGS coding scheme's coding efficiency is, there exists much temporal redundancy on the enhancememt layer. In this paper, two MC FGS structure based on using motion compensation on the enhancement layer are developed to get higher coding efficiency. Both of them exploit the temporal redundancy of the enhancement layer. After comparing both structures, one is recommended by this paper. The experimental results prove that the performance of scheme presented by this paper is better than that of MPEG-4 FGS.关键词：video streaming;FGS;coding efficiency;motion compensation;MPEG-42378|196|0更新时间：2024-05-07
- 摘要：At very low bit rates,the video coder based on matching pursuits proposed by Neff and Zahor can avoid producing visual-sensible block artifacts and has been proved to have better coding performance, compared with H.263 standards. But, the computation complexity of its realization is much too higher than traditional coders, because it needs to search optimal matching atoms in a redundant dictionary,and the searching burden strongly affects the efficiency of the coder. In order to advance the efficiency of traditional coders, The author first analyzes the atoms searching scheme based on energy priority, then develops a improved full searching scheme and a weighted searching scheme based on energy priority, Both novel time-frequency atoms searching algorithms improve the optimal time-frequency atoms searching scheme. At the same time, we compare and experiment the coding performance and computation efficiency of our algorithms.2693|207|0更新时间：2024-05-07
- 摘要：Constraint-based parametric description and inferring is one of the host spot in the research of computer-aided design, the solution to under constraint graph is a basic question in parametric design, this paper presents a series of solving methods for sketch drawing based on the priority of under constraint. This article gives general methods for under constraint graph and its basic features firstly, a new method for the solution to under constraint graph in sketch drawing is put forward, in which required apparent constraints are replaced by concealed constraints. The directed process of constraint graph is completed by picking concealed constraints of adjacent entities in sketch of few or no dimensions. In this paper, the priority of concealed constraint is given by the different constraint types and constructing orders, and some more priority concealed constraints are forced into obvious ones by the need number of constraint for every node in constraint solution process.2562|206|0更新时间：2024-05-07
- 摘要：Recently, research onVisual Speech attractsmore and more attention. It has become a very active research field of the Human-Machine Interface. The chief information relative to speech is lip motion, face, and even the whole head, which is called “Talking Head”. To synthesis a lifelike three-dimension (3D) talking head model, a novel method is proposed in this paper, which is based on an individual independent 3D-model and photos of human face. At first, the features of face shape and the position of facial organs are extracted from a front-face and a side-face phototo revise the 3D-model and make it adaptthe real person. Then, the textures of the skin and hair are picked from the photos and pasted on the revised 3D-model to make it looks like the person. This method integrates the techniques of 3D-model based modeling and photo lib based modeling, and has both of their advantages: the model has strong flexibility of synthesizing lip motions and expressions, can be rotated freely, can be synthesized in real-time, and can achieve a highly natural, lifelike 3D talking head visual effect. Then, the model is applied in a visualText-to-Speech (TTS) talking head synthesis system, and gets a satisfying result.2729|208|0更新时间：2024-05-07
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