Table of Content

25 June 2012, Volume 41 Issue 3

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学术论文

Solution of Exterior Orientation Parameters for High-resolution Satellite Imagery based on Quaternion Differential Equation

2012, 41(3):  0-416. 

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According to analyze the imaging mechanism of high-resolution satellite imagery, a solution of exterior orientation parameters based on quaternion differential equation is presented. In this solution the unit quaternion is used to describe the attitude of the image, and then the rigorous geometric model based on quaternion differential equation is build. In order to solve this rigorous geometric model, three independent parameters are introduced to this solution. So that, it is not should to solve the unknown quaternion directly, but these three independent parameters, and the unknown number keeps the same as the existed method in photogrammetry. In addition, Tikhonov regularization theory is also use to solve the rigorous geometric model. Experimental results indicate that this solution, which can avoid computation of trigonometric functions completely, is right, stable and adaptive, and the orientation precision can be improved when these three independent parameters are used.

An Automated Image Registration Method with High Accuracy Based on Local Homography Constraint

², ³, ⁴

2012, 41(3):  0-416. 

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This paper proposes a robust image registration algorithm which includes the following two stages: (1) initial matching. SIFT matching method and the normalized cross correlation (NCC) metric modified with adaptive scale and orientation of SIFT features are proposed to find good initial matches, and the geometric consistency check is used to identify false matches; (2) matching propagation. A robust matching propagation using adaptive NCC and local homography constraint starts from the initial correspondences established in the first phase, and the geometrical consistency check is used simultaneously to eliminate the incorrect matches. By using matching propagation, we can get control points used to image registration as many as possible. Initial local homography is estimated using least squares matching algorithm and the initial values of unknown parameters needed for it is provided by adaptive NCC method. Compared to existing point-based image registration methods, the proposed algorithm has better performance in terms of registration accuracy and robustness to geometric deformations within images.

Phase Unwrapping Algorithm with Difference Filter for Multi-band InSAR

2012, 41(3):  0-416. 

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A new phase unwrapping algorithm with difference filter for multi-band InSAR was proposed by taking zero intermediate frequency vector filtering of interferogram for reference. It differences the interferogram with shorter wavelength to the one with longer wavelength to reduce the frequencies of fringes, as can improve the effects of filtering and phase unwrapping. It unwraps the phases with shorter wavelength based on the unwrapped phases with longer wavelength. All the phases in interferograms with different bands are used in phase unwrapping, so the reliability and the precision of phase unwrapping are improved. The simulated multi-band interferograms from DEM were applied in phase unwrapping experiments. The unwrapped phases were satisfying, as validated the proposed phase unwrapping algorithm.

Calibration of Angular Systematic Errors for High Resolution Satellite Imagery

2012, 41(3):  0-416. 

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The object positioning accuracy from high resolution satellite imagery is strongly relevant to image attitude data accuracy, but the attitude data have generally systematic errors and the object location becomes unreliable. This paper proposes an angular systematic error calibration model, which is stricter than constant angular error calibration model, based on the rigorous geometric processing model of high resolution satellite remote sensing imagery. The calibration model was tested on SPOT-5 and CBERS-02B images and both have proved its correctness. After compensating the angular systematic errors of images, the direct georeferencing accuracy can reach ±2~3 pixels, which is much better than results of constant angular calibration.

A Fitting Algorithm of the Apparent Moon Center and Its’ Application on Fast Orientation

2012, 41(3):  0-416. 

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Based on observing the edge of the bright part of the apparent moon by electronic theodolite, a fitting algorithm of the apparent moon center was put forward in this paper, and formulae were deduced in detail. Experiment based on real observation testified the stability of the algorithm, which demonstrated the position of the moon center was solved precisely. Then, a novel method of fast orientation by surveying the moon was explored, with which orientation was realized successfully and both inner and outer precision of orientation could be superior to ±2.0″. The moon-observing method can overcome the shortage that classical astro-geodetic orientation can only be realized by star-observing method at night, and extend the application field of astro-geodetic surveying effectively. Since the apparent sun is a circular plane, the moon-observing method will be suitable for observing the sun. Definitely, fast orientation by observing the moon or the sun has a bright future in application.

Airborne Linear CCD Sensor Geometric Calibration Based on Self-Calibration

2012, 41(3):  0-416. 

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In the paper the self-calibration bundle block adjustment technique based on the additional parameters is applied to the airborne linear CCD sensor geometric calibration. Taking the ADS40 sensor for example，the integrated sensor imaging relationship is analyzed firstly, and then the GPS observations model, the IMU misalignment angle model and the self-calibration bundle block adjustment model for the calibration are set up. Upon the detailed investigation on the imaging error properties, the suitable sensor calibration parameter model is built up. Finally the ADS40 data on the test field is used for the calibration experiments. Experimental results prove that the geometric calibration method is correct and effective,which can significantly improve the measuring accuracy and the reliability.

An Improved Autofocus Algorithm for SAR Images

2012, 41(3):  0-416. 

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The current windowing method and prominent point selection of phase gradient autofocus (PGA) algorithm are not generalized, therefore this paper presents an improved algorithm for the PGA. The algorithm presents a new method to determine the Point Spread Function (PSF) support domain of the phase error, which calculates the average energy distribution of azimuth direction as the average energy outside the support domain, in order to determine the width of the window. Based on this adaptive windowing method, this paper also proposes an improved method of selecting prominent point, which can select the prominent points of big signal-to-noise ratio (SNR) and remove the prominent points of small SNR. Compared to the traditional windowing method and prominent point selection, the method of this paper can get a better focus result, which is demonstrated by the experiment.

InSAR Phase Unwrapping Using Least Squares Method with Integer Ambiguity Resolution and Edge Detection

2012, 41(3):  0-416. 

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In order to overcome the problems of poor convergence and integer ambiguity solution in phase unwrapping based on least squares method, an improved method of phase unwrapping is proposed based on unwrapping edge detection in this paper. The unwrapping edge is predicted and propelled by comparing the optimal solutions and suboptimal solution in least squares method. The integer ambiguity of unwrapped phase is detected and extracted through an attempt to use additional phase increment into wrapped phase. The feasibility and accuracy of proposed method is tested and validated by using simulated data and ERS-1/2 InSAR interferogram covering Hong Kong and Shen Zhen area. The testing results show that the proposed method can correctly extract 99.5% phase values from the simulated interferogram with strong noise. The accuracy of phase unwrapping tested on the InSAR interferogram reaches ±0.12rad.

The Method of Generating Contour Tree Based on Contour Delaunay Triangulation

2012, 41(3):  0-416. 

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Contour tree is an effective method to express the spatial relations of contour lines. The adjacent relationship and inclusion relationship of contour lines can be expressed clearly by contour tree. Contour tree facilitates the processing of contour lines. This work studies how to construct contour tree by using of Delaunay triangulation, proposes a new method of generating contour tree. It fully uses the advantages of Delaunay triangulation in Domain Analysis, determines the spatial relationship of contour lines by using Delaunay triangulation twice, then unifies these contour lines which are truncated by figure profile to achieve the purpose of generating contour tree. In this work contour lines are used as a constraint edge to build a constrained Delaunay triangulation. Contour lines with neighboring relations are found by using of Delaunay triangulation. On this basis, the truncated contour lines are ascertained, identified and unified ultimately through combining the elevation of their neighboring contour lines. Then the two contour lines with neighboring relations are found again after the contour lines reunification by using of Delaunay triangulation. By using the elevation of the two contour lines to judge whether they are brothers or father-son relationship. The contour lines are inserted into the appropriate position in tree according to the relationship. And the contour tree grows gradually. This paper also gives algorithm design of the method of generating contour tree based on Delaunay Triangulation and experimental results.

Generalized Regularization to Ill-posed Total Least Squares Problem

,WU Ji-Cang

2012, 41(3):  0-416. 

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By formulating a more reasonable Error—In—Variables (EIV) model, total least squares method has been wildly used in recent years. Based on ill-posed least squares theory, coefficient matrixes are always ill-conditioned, and which will cause the results oscillate. The regularization is a well-known tool for solving these problems. In fact, total least squares method is a deregularizing procedure, so the ill-posed problems will be more serious. That means errors in the data are more likely to affect the total least squares solution than the least squares solution. In this paper, we propose using generalized regularization to solve ill-posed problems in total least squares, so as to improve stability of the results. Finally, numerical experiments are carried out to demonstrate the performance and efficiency of the generalized regularization method which have significant advantages in solving ill-posed problems.

The Modified Algorithm of Image Edge Features Detection Based on 2-D Discrete Hilbert Transform

2012, 41(3):  0-416. 

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A novel algorithm is proposed based on 2-D Discrete Hilbert Transform. It has been verified that Hilbert transform can be used to detect the edge features from images. The magnitude of signal is not changed, and the phase is shifted in frequency domain after transforming by Hilbert transform. Namely, when the signal is negative, the phaseshift is +90°; when it is positive, the phaseshifit is -90°. There are peaks and valley on features of signal after Hilbert transform. Thus, this paper proposes the 2-D discrete Hilbert transform to detect image edges. Because of the directionality of the 2-D discrete Hilbert transform in edge detection, we calculate the quadratic sum of two orthogonal 2-D discrete Hilbert transforms to complete the edge detection. Furthermore, Gaussian function is introduced into the 2-D discrete Hilbert transform to reduce the influence from noises, and PSNR (Peak Signal to Noise Ratio) is used to determine the optimal parameter σ. An evaluation between the propose algorithm and the others is realized to verify the result of edge detection. Remotely sensed imageries are chosen as test data in edge features detection. The results of detection show that the proposed algorithm is effective in edge features detection.

A Dimensionality Reduction Method for hyperspectral imagery based on Local Discriminative Tangent Space Alignment

2012, 41(3):  0-416. 

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Nonlinearity in Hyperspectral Imagery is an inignorable property. Many manifold learning methods can exploit this feature to reduce the data’s dimension by preserving local topological structures and finally effectively improve the land-cover types classification accuracy. However, most of them can not model both the intra-class geometry and interclass discrimination information simultaneously. In this paper, a Local Discriminative Tangent Space Alignment (LDTSA) based dimension reduction method is proposed. It applies the idea of part optimization and whole alignment and considers encoding the geometric and discriminative information in a local patch. Extensive experiments demonstrate the effectiveness of LDTSA compared with representative dimensionality reduction algorithms. 1) LDTSA avoids the small-sample-size problem; 2) LDTSA preserves the discriminative ability; 3) LDTSA preserves the distribution nonlinearity of observations.

Automatic Viaduct Detection with LiDAR and RS Image

²,Xianfeng Huang³,

2012, 41(3):  0-416. 

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An automatic method for viaduct detection with LiDAR data and remote sensing image is presented in this paper, according to spatial characters of urban complex viaduct. The flowchart and key technologies of the method are discussed in detail. The feasibility and performance of the suggested techniques are verified through experimental results with real data.

The Algorithm of Single-epoch Integer Ambiguity Resolution between Long-range Network RTK Base Stations

2012, 41(3):  0-416. 

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The algorithm of integer ambiguity resolution between long-range base stations at single-epoch is proposed in this paper. The wide-lane ambiguities are determined by linear relationship between carrier phase ambiguities. In order to reduce the residuals of non-divergent error in carrier phase ambiguities resolution, a new idea of reselecting base satellite by elevation is used. Then candidates of double frequency carrier phase ambiguities can be selected by fixed double difference wide-lane ambiguities. The double difference carrier phase ambiguities are searched and fixed through the computation of non-divergent error’s residual. This algorithm was tested, and the advantages of this method are rapid, stable, and this algorithm avoids the effect of cycle clips. The double difference integer ambiguity between long-range base stations can be fixed at single-epoch.

A Method for Constructing an Adaptive Grid Digital Depth Model Based on Mean Vertical Uncertainty of Area

2012, 41(3):  0-416. 

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A method for constructing an adaptive grid digital depth model based on mean vertical uncertainty of area is proposed. Depth uncertainty and its propagation mechanism is used for estimating the mean uncertainty of depths in the modeled area, levels of grid partition are determined automatically and depths are organized effectively; constraint conditions at common nodes of adjacent areas are added for making the depth model continuous. Experimental results demonstrate: (1) in the area where the depth change trend is not consistent, the method based on mean vertical uncertainty of area has the higher quality than the method with equal spacing and the method considering depth complexity; (2) The method based on mean vertical uncertainty of area is able to determine the grid spacing automatically and make the model quality meet the design requirements while the regular grid method is not; The method based on mean vertical uncertainty of area is more adaptive than the method considering depth complexity. (3) The method based on mean vertical uncertainty of area is more automatic and efficient than the method considering depth complexity.

EMD-ICA with Reference Signal Method and Its Application in GPS Multipath

2012, 41(3):  0-416. 

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Multipath error is a main influence of high-precision GPS dynamic deformation monitoring as it is difficult to be mitigated by difference observation in most of applications. If the local environment of the antenna is unchanged from one day to another, the multipath error will nearly be the same. So establishing the error correction model with repeatability characteristics is a valid method to mitigate multipath error. However, the repetition of multipath error reduces along with time passing. What is more, as the frequency range of multipath error is wide, it may mix with the low- Frequency of vibration signals. The traditional methods usually process in frequency domain, so that it can’t deal with such error. Therefore, a method called EMD-ICA with reference signal is proposed. It combines Empirical Mode Decomposition (EMD) with independent component analysis (ICA). The test shows the effectiveness of this method.

Annotation Scheme for Spatial Relations in Chinese Text

2012, 41(3):  0-416. 

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Natural language describes the nature of people’s internal representation of space. The primary means for exchanging spatial information is natural language. The interpretation of geospatial expressions in natural language and the comparison of the semantics of spatial terms in different languages are special arguments for bridging semantic gap between natural language and computational models in geographical information systems (GIS). The understanding of spatial relations described in natural language has been addressed as one of the most fundamental issues of GIS. It can be divided into two steps, i.e. recognition of their linguistic structure and interpretation of spatial semantics. Corpus annotation is a task to identify specific spans of text which exhibit linguistic structures linguistic structures (e.g. words, phrases etc.) and to create metadata describing them to allow computer direct access to the structures. Annotation schemes made to a corpus are a necessary resource for the development of text processing tools and eventually automatic information extraction system, providing both reference and training material for method development and benchmark data sets. Base on the analysis of linguistic characteristics, this paper proposes an annotation scheme for markup linguistic expressions of spatial relations in Chinese text, and explores detailed annotation specification. Furthermore, GATE（General Architecture for Text Engineering）is introduced as the annotation platform. An annotated corpus based on " Encyclopedia of China Geography " (2,130,000 bytes of Chinese text ) is established by means of cross-validation, in order to solve the problem of inconsistency in the decision of types of spatial relations in text. Finally, performance of the proposed annotation scheme and the annotated corpus is evaluated and analyzed, and some related problems are discussed for further improvement. In conclusion, this study provides a benchmark dataset for interpretation of spatial relations in Chinese text. It can help people more in-depth understand the mechanism of geospatial cognition and spatial language, and then improve the intelligence of GIS spatial query, spatial reasoning, and geographical information retrieval.

Gravity Anomaly Calculation Based on Volume Integral in Spherical Cap and Comparison with the Tesseroid-Taylor Series Expansion Approach

2012, 41(3):  0-416. 

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The gravity or gravity anomaly calculating methods must be developed from the rectangular Cartesion coordinate system to the spherical coordinate system when utilizing gravity data to study the regional and global geologic problems. The method of surface integral approximation for gravity anomaly forward in spherical cap is improved so that both calculation accuracy and computing speed are enhanced. By means of the model testing, the calculation accuracy and stability of the methods of gravity anomaly calculation in spherical cap and the Tesseroid-Taylor series expansion are analyzed, and the conclusions are drew that the Tesseroid-Taylor series expansion approach is affected by the expansion order, surface area, thickness, depth and surface position of the Tesseroid, and the height of the calculating point, while the method of surface integral approximation in spherical cap by the thickness and depth of the Tesseroid, and the height of the calculating point and the accuracy of model reconstruction, but the method proposed in this paper only by the model reconstruction. the Tesseroid-Taylor series expansion approach, which does not require coordinate rotation and model reconstruction, is fit for 3-D density imaging by gravity data, but the calculating method in the spherical cap, which has high accuracy and stability, is suite to local, regional and global gravity or gravity anomaly forward modelling.

Bayesian Methods for Outliers Detection in Autoregressive Model Based on Different Types of Classification Variables

2012, 41(3):  0-416. 

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Abstract: In this paper, a Bayesian procedure for outliers detection in time series is considered. The main idea of this method is introducing different types of classification variables into autoregressive model. Then outliers can be detected by comparing the posterior probabilities of these classification variables with a threshold. Besides, a new method about computing the posterior probability of each classification variable and obtaining the estimators of outliers is designed by Gibbs sampling. Moreover, a large number of experiments and applications are made for the proof that the new procedure is able to detect additive and innovational outliers occurring in time series at the same time or not.

Estimation of the resolution of Earth’s gravity field for GRACE Follow-On using the spectrum method

2012, 41(3):  0-416. 

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In this paper, the spatial resolution of the earth’s gravity field for the future Grace Follow-On is discussed by analyzing the spatial disturbance gravity spectrum and the accumulative geoid error spectrum. The radial disturbance gravity with the height 200 and 250 kilometers was computed, using the EGM96 gravitational field model. Analyzing the radial gravity disturbance spectrum characteristics, a new earth’s gravity field model of 281 and 242 degree can be recovered at the two orbit heights. The accumulative geoid error spectrum model is given, and the accumulative geoid error spectrum at the height of 200 and 250 kilometers is computed. Analyzing the accumulative geoid error, we can conclude that the earth’s gravity field can be recovered to a degree of 286 and 228.

Application of Modern Signal Processing Methods to Sky wave Delay Estimation of Loran C Signal

2012, 41(3):  0-416. 

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For insuring accuracy and validity of the Loran C signal sky wave delay estimation in low SNR, correlation coefficient time domain method based on optimization envelope is presented. First, the paper analyses the characteristic of standard Loran C signal envelope, and uses differential and Quadratic differential of Loran C envelope signal respectively in order to form the steep rise-time of envelope signal. Second, receiving signal envelope and reference signal envelope are matched by correlation coefficient time domain method, then the matching peak results correspond the arriving time of ground wave and sky wave signals respectively. Hence, sky wave delay estimation time is got. At last, through the simulation analysis and the measured signal test, it is proved that the method meets digital receiver’s needs, and has the characteristics of higher the anti-jamming ability，estimation accuracy and automatic identification function. At the same time，the estimation result serves as auxiliary basis that judges the precision rate of phase track and cycle identification.

测绘快报

China’s First Civilian Three-line-array Stereo Mapping Satellite: ZY-3

2012, 41(3):  0-416. 

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Abstract: May 18th, 2012 is the 10th anniversary of Academician Wang Zhizhuo’s death. As early as 1965, Academician Wang Zhizhuo had forecasted that the future artificial satellite would provide mapping personnel with images to compile and edit topographic maps in his article “The modern development of aerial javascript：void(0);photogrammetry ”.On January 9th, 2012, China launched its first civilian three-line-array stereo mapping satellite, ZY-3. This article has simply introduced the platform and load of ZY-3 as well as the preliminary results of ground process, image products and on-orbit testing, which is published to commemorate Academician Wang Zhizhuo.

Technologies Connotation and Developing Characteristics of Open Geospatial Information Platform

2012, 41(3):  0-416. 

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Based on the background of developments of surveying, mapping and geoinformation, Aimed at the demands of data fusion, real-time sharing, in-depth processing and personalization, this paper analyzes significant features of geo-spatial service in digital city，focuses on theory, method and key techniques of open environment of cloud computing, multi-path data updating, full-scale urban geocoding , multi-source spatial data integration, adaptive geo-processing and adaptive web mapping. As the basis for it, the Open Geospatial information platform is developed, and successfully implicated in digital Shenzhen.