Table of Content

25 October 2011, Volume 40 Issue 5

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学术论文

Study on data structure of line map symbol based on PostScript

2011, 40(5):  0-0. 

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This paper aims at data structure of line map symbols. Firstly, graphic composition pattern and rendering efficiency in three classic structures of line symbol which contained cell-cycle, line-type overlay and function method were analyzed. Secondly, a structure and storage method based on PostScript imaging model were proposed for uniformly describing control axis in line symbols. Thirdly, three types of strokes which contained color-stroke, cell-stroke and raster-stroke were designed. They supported the two composition model of cell-cycle and line-type overlay, and could design cartoon and artistic symbols. Fourthly, an object called decoration was brought to design complex line symbols such as scarp symbol, and a rendering style based on contour transformation was proposed to support half-line & half-area symbol design as well. Any line symbol was composed of path, stroke, decoration and contour transformation. Finally, a prototype system was developed to conduct the experiments of efficiency comparison and multi-media output. Experiments show that this structure can render line symbols efficiently by decomposing them. It supports complex line symbols design and can export map symbols to computer screen for display, web for transmission and paper for printing easily.

Boresight Misalignment Calibration of Airborne Position and Orientation System Based on Photo Nadir Point

2011, 40(5):  0-0. 

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According to the theory of vanishing point, a novel approach to calibrate the boresight misalignment of airborne position and orientation system (POS) based on photo nadir point is proposed. First, the strict mathematical relationship between the photo nadir point and the boresight misalignment of airborne POS is established and the error equations for solving the boresight misalignment are derived. Then, a set of actual images are tested. The empirical results show that the mathematical model established in this paper is correct and the boresight misalignment could be calibrated by using more than two photo nadir points. The proposed method does not need a specific calibration field and ground control points. Therefore, it has practical application value to calibrate the boresight misalignment when taking large-scale aerial photography over urban areas with POS.

Research on User Profile Extended Model for Intelligent Distribution of Spatial Information

2011, 40(5):  0-0. 

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Blind Watermarking Algorithm Based on Mapping Mechanism for Remote Sensing Image

2011, 40(5):  0-0. 

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A blind watermarking algorithm resistance against the geometric attacks for remote sensing data is presented based on mapping mechanism. First, the pseudo-random binary sequence, which is generated by the random number generator, is used as the watermarking information. Then, the mapping function of the image data and watermark information is established, and the mapping variable is expanded, which can determine the watermark embedding position. Finally, the modified pixel value bit-plane, which is based on mapping mechanism, is used as the watermark embedded rules. Watermark detecting is the inverse process of watermark embedding, and the watermark information is determined by majority rule. The presented method overcomes the limitation that the image size and the pixel relative coordinate remain the same after the traditional attacking. The watermark capacity has been effectively expanded, and the presented method has good robustness, invisibility and maintains the accuracy of features and statistical properties of image.

Structural Segmentation of 3D Buildings Based on Voxel Analysis

2011, 40(5):  0-0. 

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博士论文摘要

Precipitation Retrieved by Doppler Radar and Its Assimilation Study with the Improved Regional Climate Model RIEMS

2011, 40(5):  0-0. 

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InSAR Atmospheric Delay Correction Based on GPS Observations and NCEP data

2011, 40(5):  0-0. 

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学术论文

A Method of Edge Feature Detection from High-resolution Remote Sensing Images Based on Frequency Spectrum Zone Energy

2011, 40(5):  0-0. 

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In view of the characteristics of high-resolution remotely sensed imagery, a novel edge feature detection algorithm based on frequency spectrum zone energy was introduced in this paper. From the perspective of energy of image signal, the methods of sliding-window fourier transformation and frequency energy sectional superposition were used to decompose signal into different frequency spectrum zones. Then according to good noise suppression capacity of DC (Direct Current) central frequency spectrum zone image, contribution degree of higher-order frequency spectrum zone energy to the image edge feature was further analysed. Finally, we obtained the edge detection result through aggregating spectrum energy coefficient within each window radius of frequency spectrum range from 1 to 1.5 and quantizing image gray between 0-255. The experimental results shows that this algorithm remains good edge of image and has good capability of edge detection in a specific direction as well. The proposed method and thought has certain theoretical significance and practical reference value for image segmentation and object-oriented image recognition.

Patch-based Least Squares Image Matching Based on RPC Model

2011, 40(5):  0-0. 

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Since patch-based least squares image matching only applies to the production of regional DSM that based on single-center projection with frame imaging, patch-based least squares image matching based on RPC model is proposed, which extends patch-based least squares image matching from single-center projection with frame imaging to stereo-matching of multi-center projection with push-broom imaging, and the algorithm is proved by the experiment with SPOT5-HRG stereo images. The experimental results show that RPC model can be used in patch-based least squares image matching to improve its applications and value.

A wavelet SCM algorithm used to detect cloud in remote sensing cameras

2011, 40(5):  0-0. 

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The satellite’s storage device and downlink bandwidth are facing great challenges with the improvements of cameras’ resolution and swath width。However, 33%-50% of the remote sensing images are clouds, and these images are almost useless for losing the information on ground objects. This paper proposed a new multi-branches cloud discrimination algorithm to control the camera stop photo in cloud area. Firstly, the spectrum threshold method is used to distinguish between clouds and ground objects roughly. Then the texture analysis method is adopted after threshold method invalid. To reduce the false alarm rate, a new method based on wavelet SCM is used to extract texture properties, and a bi-judgement method based on ASM and entropy is proposed. The algorithm has been verified by 245 remote sensing images. The experimental results show that this algorithm can detect clouds and ground objects correctly, and the false alarm rate is lower than 5%.

Indicator-Driven and Task flow-centered Online Interactive Mapping Model

2011, 40(5):  0-0. 

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Online mapping is a very complex and interactive process. This paper expounds the various models that are used for cartographic information systems and which we are now adapting for web cartographic interaction application. In order to make mapping easier in the context of web,Indicator-Driven and Task flow-centered Online Interactive Mapping Model is put forward based on characteristics of statistical indicators and cartography visualization. Its concept and schema is discussed,and some examples are presented.

Application of Intertidal Zone Extraction Based on Remote Sensing Images Fusion Technique

2011, 40(5):  0-0. 

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A new intertidal zone extraction method based on satellite remote sensing images fusion is presented to overcome the shortcomings of the lacking of intertidal zone data and the single extraction method. The Shift-invariant Discrete Wavelet Transform(SIDWT) algorithm is used for fusing SAR and panchromatic remote sensing images which are photoed on different time of the same tidal periodicity. And in the fusion processing, a new fusion rules is presented for complementarity information enhancement, the fused approximate coefficients are obtained by weight rule based on edge extracting, maximum absolution value rule is adopted to fuse the detailed coefficients. Thus the new fused image can outstand the tide Intertidal shape, coast line and alongshore zone characteristic for visual interpretation easily. Experimental results for real images demonstrate the effectiveness of the algorithm proposed in this paper.

Baseline Estimation Algorithm of InSAR with Block Adjustment

2011, 40(5):  0-0. 

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Baseline Estimation is important for deriving accurate heights in processing of InSAR（Interferometric Synthetic Aperture Radar）. It needs large quantities of ground control points with proper placements to estimate baseline parameters for multiple InSAR data that cover large areas if adopting baseline estimation algorithm for each pair of data. What’s more, there will be great difference between heights derived from different data due to the errors of baseline estimation. A new baseline estimation algorithm with block adjustment considering phase offset was proposed to reduce the needed ground control points and the difference between heights derived from different data. The experiments of baseline estimation with block adjustment were done with multiple pairs of InSAR data obtained by airborne InSAR system researched by Institute of Electronics, Chinese Academy of Sciences. It used less ground control points, and the difference between heights in overlap areas was reduced, as validated the proposed baseline estimation algorithm.

Network Transmission Mode for Multi-resolution Image Based on P2P

2011, 40(5):  0-0. 

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In network environment, network transmission and multi-resolution display of massive image data is the key to view large-scale image graphics. Based on a traditional client / server architecture, with the increase of users, there are the problems that the load of server is too large, and transmission efficiency decreases and so on. This paper presents a P2P-based image transmission mode which uses of peer to peer network structure, refers to P2P file download technology. The mode that is based on classification methods of image block, constructs a multi-tracker overlay network based on regional interest groups, optimizes the peer joining algorithm, the neighboring nodes selection algorithm and security strategies. Simulations experimental results have shown that the neighboring nodes selection algorithm optimizes the performance of network transmission, and then develops a prototype system IMAGEP2P.

An Adaptive Water Body Information Extraction Method Using RS TUPU Computing Model

2011, 40(5):  0-0. 

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To extract water body through remote sensing technique is a practical and effective method. Considering the advantages of the features of spatial clustered layer and non-linear spectral mapping layer, the RS TUPU computing mechanism is designed, which aims to approach the accurate regional boundary of thematic area step by step. Meanwhile, extraction parameters in the process are adjusted automatically by adaptive information computing method. Subsequently, the RS TUPU computing model is proposed, which will be applied in water body extraction case later. Before that, the existing valid methods for water body extraction are analyzed first in the paper. On this basis, an adaptive water body extraction method using RS TUPU Computing Model (WERSTP) is proposed, where ETM image is selected as experimental data source. The experimental results show that the method, which is based on the advantage of index based and spectral-classification based extraction method as well as introducing the distribution features of water space, provides an effective extraction result to make it achieve the level of accuracy and automation in water body information extraction.

Generation of Levels-of-Detail of 3D Building Models Based on Cutting Loops Decomposition

2011, 40(5):  0-0. 

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Automated generating Levels of Detail (LOD) of 3D building models is a crucial problem in Geographical Information Sciences (GIS), Virtual Reality (VR), Real-time Visualization, and Progressive Transmission (PT). This paper proposes a cutting loop decomposition approach for generating LOD of 3D building models. Firstly, the cutting loops of 3D building model are detected according to a dihedral angle operator. Secondly, the building model is decomposed into the main body and a series of feature parts through the cutting loops, which are stored as nodes in a CSG-tree. Finally, the nodes in the CSG-tree are selectively simplified according to the significance of each node. The experimental results show that the proposed approach is efficient and able to preserve the structural features of the building models.

Determination of Main Error Source on Vertical Parallax of POS Data and Research of Regression Model

2011, 40(5):  0-0. 

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Main reason of the existence of systematic error of POS data is analyzed. Error equation of POS-based relative orientation is deduced. Regression model to compensate the systematic error of POS is established. Three sets of aerial images in different scales with POS data are used for experiment. Experimental results show that the systematic error of angular elements in POS data is the main error source which causes large vertical parallax. Compared with original POS data, the POS data corrected by the regression model can significantly decrease vertical parallax. Accuracy of geo-referencing is considerably improved without block adjustment. Satisfying result of experiment verifies the correctness and feasibility of the regression model.

Building & Validation of Rigorous Geometric Model of ALOS PRISM Imagery

2011, 40(5):  0-0. 

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Based on the principle of ALOS/PRISM, a rigorous geometric model is established by imagery ancillary data. This progress can be seen as a series of coordinate system ransforming. Then we use the rigorous geometric to achieve for georeferencing of ALOS/PRISM imagerys. Experimental results show that there would be constant systematic errors existed in side watch angle. In order to eliminate the systematic error, a new matrix was introduced. It is used to rectify the look direction in ECR coordinates. Once the systematic errors are eliminated, the result is improved noticeably. Accuracy is better than 5m for the planar position and 3m for the altitude It shows that the improved rigorous geometric model is very stable and the accuracy of direct georeferencing is also very ideal. However, in different areas, the accuracy is a little different. In 003 and 004 imagery, horizontal accuary and vertical accuary are about 2m; In 005 imagery, horizontal accuary is about 5m and vertical accracy is better than 2m. The result suggest that the change of side watch angle may act on the final orientation accuary.

Translation Invariant Omnidirectional Lifting Based Remote Sensing Image Denoising

2011, 40(5):  0-0. 

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After analyzing remote sensing image structure and its main difference from noise signals, this paper utilizes directional information in image signal and proposes a translation invariant omnidirectional lifting (TI-OL) for remote sensing image noise removal. By integrating cycle spinning, Gabor wavelet filter and image rotate skills into traditional adaptive directional lifting (ADL), the proposed algorithm overcomes three drawbacks in ADL as lacking of translation invariance, inefficiency in local direction estimation and limited transform direction distribution. In this way, the proposed method can reduce Gibbs effects in the denoising result, promote the accuracy of orientation estimation and guarantee an optimal representation for textural information. Experimental results demonstrate that the proposed method can effectively remove noise while protecting the image detail information. It outperforms state-of-art denoising algorithm in terms of both objective (PSNR) and subjective (SSIM) evaluation.

The Simplification model of Linear Objects Based On Ant Colony Optimization Algorithm

2011, 40(5):  0-0. 

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In map generalization, it’s important to simplify linear objects. As a patch against other optimization algorithms, ant colony optimization algorithm in solving combinatorial optimization problems has some advantages, such as faster convergence and is more closed to problem-solving habits of the human. The simplification of linear objects can be looked upon as an optimization problem about partial selection. According to the purpose for simplifying linear objects, the standards on map production and the basic principles of ant colony optimization algorithm, the simplification of linear objects is explained as a kind of combinatorial optimization problem, and the constraints that should be satisfied in the simplifying process are described by mathematical formulae at first in this paper. Then a model of automated simplification using ant colony optimization algorithm is put forward in detail and the key steps are given. In order to improve operational efficiency of the algorithm, long-term taboo list and the local search strategy are introduced. Finally, the algorithm is tested and compared with Douglas algorithm, the results demonstrate that the proposed model to the automatic generalization of linear objects is feasible and effective, and the objective function values obtained from ACO algorithm are better within the same geometric tolerance. Using the proposed algorithm the basic geometric characteristics of linear objects are maintained, and a higher compression ratio is achieved while taking into account length deviation and vector deviation.

Dense Matching for Wide Base-line Stereo Images Based on SIFT

2011, 40(5):  0-0. 

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A novel multi-stage quasi-dense matching algorithm for wide base-line stereo images is introduced based on SIFT and dual constraints of epipolar geometry and homographic mapping. The proposed algorithm includes following three stages: (1) the optimal SIFT features with good spatial distribution and large information content are first selected, and matched by using the least squares matching method, then the fundamental and homographic matrix can be estimated by using these initial sparse correspondences with higher precision; (2) For the other SIFT features, affine transformation parameters between matching windows are iterative optimized by using the slope angle of correspondent epipolar lines and scale information of SIFT features, and affine invariant feature descriptors are extracted from the corrected matching windows, then correspondences can be determined by Euclid distance and dual constraint information; (3) Considering the lower repeatability rate of feature detection for wide base-line stereo images, for the unmatched points extracted from left and right images of stereo pairs, matching can be carried out by adopting two-way search strategy from left to right image or from right to left image based on the rapid SSD similarity cost function and affine rectified dual constraints region, and the least squares curve surface fitting weighted by Gaussian-distance algorithm is adopted to improve the precision of matching results. Test results using practical wide base-line image pairs indicate the effectiveness of the proposed algorithm and can provide reliable dense or quasi-dense matching points for subsequent 3D reconstruction.

Terrain Viewshed Analysis Method Based on Distance Field Mapping

2011, 40(5):  0-0. 

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Terrain viewshed analysis is an important content of terrain analysis, and a new method based on distance field mapping is given to solve the problems the existing methods have, such as complexity in computation and bad applicability. First, the terrain was rendered with perspective projection from the view point, and the distance between the view point and the visible points on terrain surface was saved into a distance map as output; then, the terrain was rendered again with orthogonal projection from top view, and the visibility of the fragment was obtained by comparing the distance from the fragment to the view point and the distance field mapping value. At last, a displaced sampling method was given to reduce the aliasing artifacts. Results show: the method can efficiently yield visibility results of high accuracy; in addition, it is applicable for different terrain models even with objects on them, because the algorithm is independent of geometry.

A Globally Convergent Algorithm of Space Resection Based on Quaternion

2011, 40(5):  0-0. 

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The traditional solution of space resection in photogrammetry is expanding the collinear equation according to Taylor formula to obtain the linear equations, and then the linear equation is solved iteratively by the least square principle. The precision of the solution is greatly related to the initial value of exterior orientation elements. In order to solve this problem in theory, a globally convergent algorithm of space resection based on quaternion is presented by combining good application of quaternion in photogrammetry. Firstly the unit quaternion is used to describe the attitude of the image in this algorithm, and absolute orientation equation and orthogonal projection formula are used to replace the collinear equation. Then the iterative solution of nonlinear equation is used to solve this problem. So that, the linearization of collinear equation is needless. Lastly the globally convergent property of this algorithm is proved in theory. Experimental results indicate that this algorithm, which is a real space resection solution independent of initial values, is right, stable and adaptive, and have no requirement for initial values of exterior orientation elements.