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Journal of Geodesy and Geoinformation Science 2020年第3期3卷 115-127页

作者： Jiguang DAI Yue GU Guang JIN Lei ZHU School of Geomatics Liaoning Technical UniversityFuxin 123000China Liaoning Aulutong Tech.LTD Shenyang 110006China Huludao Hongyue Group Company Huludao 125003China

Aiming at the problem that high-resolution optical remote sensing image,lines are prone to fracture,and a line segment optimization algorithm is proposed in this paper.Firstly,the line segment is regarded as a way to express the contour of the ground object,and the laws of line segment fracture from two aspects of geometric features and texture features are analyzed;Secondly,the line segment optimization algorithm is proposed.It takes the results of detecting line segments as the processing primitives,determines the initial optimized line segment according to the length of the line segment,establishes the tracking rectangular region and geometric constraint model for the fractured line segments,builds a dynamic optimization model,and gives a complete line optimization process.Through the analysis of experimental results of multiple actual scenes and different types of remote sensing images,it is shown that this algorithm can not only solve the problem of line segment fracture caused by terrain occlusion,edge blurring,and edge serration,but also comparing with other methods,the proposed algorithm has great advantages in optimizing line length and restraining over extraction problem.

关键词： optimization line segment constraint

An efficient algorithm to clip a 2D-polygon against a rectangular clip window

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Applied Mathematics(A Journal of Chinese Universities) 2022年第1期37卷 147-158页

作者： Sushil Chandra Dimri Umesh Kumar Tiwari Mangey Ram Department of Computer Science and Engineering Graphic Era(Deemed to be University)DehradunUttarakhandIndia

Polygon clipping is of great importance in computer graphics.One of the popular algorithms to clip a polygon is Cohan–Sutherland Hodgeman algorithm which is based on line clipping.Cohan–Sutherland Hodgeman algorithm clips the polygon against the given rectangular clip window with the help of line clipping method.Cohan–Sutherland algorithm requires traversing the polygon in anti clockwise direction(positive orientation).In this work we propose an efficient polygon clipping algorithm against a rectangular clip window.Proposed algorithm uses parametric representation of polygon edges.Using the concept of point clipping,we can find required intersection points of edges of polygon with clip window boundaries.Well suited numerical illustrations are used to explain the proposed polygon clipping method.The proposed algorithm is computationally less expensive and comprehensive.

关键词： point clipping polygon clipping clip window line segment computational complexity

Positional Error Model of line segments with Modeling and Measuring Errors Using Brownian Bridge

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Journal of Geodesy and Geoinformation Science 2023年第2期6卷 1-10页

作者： Xiaohua TONG Lejingyi ZHOU Yanmin JIN College of Surveying and Geo-informatics Tongji UniversityShanghai 200092China Shanghai Key Laboratory for Planetary Mapping and Remote Sensing for Deep Space Exploration Shanghai 200092China

Spatial linear features are often represented as a series of line segments joined by measured endpoints in surveying and geographic information science.There are not only the measuring errors of the endpoints but also the modeling errors between the line segments and the actual geographical features.This paper presents a Brownian bridge error model for line segments combining both the modeling and measuring errors.First,the Brownian bridge is used to establish the position distribution of the actual geographic feature represented by the line segment.Second,an error propagation model with the constraints of the measuring error distribution of the endpoints is proposed.Third,a comprehensive error band of the line segment is constructed,wherein both the modeling and measuring errors are contained.The proposed error model can be used to evaluate line segments’overall accuracy and trustability influenced by modeling and measuring errors,and provides a comprehensive quality indicator for the geospatial data.

关键词： spatial data line segment modeling error measuring error Brownian bridge

Optimal line Feature Generation from Low-level line segments under RANSAC Framework

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Optimal Line Feature Generation from Low-level Line Segments...

A novel feature matching algorithm against moving background for indoor video surveillance

第26届中国控制与决策会议

作者： Li Haifeng Chen Rong College of Computer Science and Technology Civil Aviation University of China

ISBN: (纸本)9781479937066

The low-level line segment features have low accuracy as they are more easily affected by the noise and differeent line segment detectors. Furthermore, the line segment is not a good feature for matching across multiple views when we need to finish the 3D reconstruction. However, the line feature is more robust for the noise. In this paper, a kind of line feature, ideal line, is defined and optimally estimated by clustering the line segments under RANSAC framework. The physical experiments are carried out to verify the proposed estimation method.

关键词： Ideal line line segment Maximum Likelihood Estimation RANSAC

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A novel feature matching algorithm against moving background...

IMPROVED HEURISTICS FOR THE MINIMUM WEIGHT TRIANGULATION PROBLEM

第36届中国控制会议

作者： Qi Hui Ma Ya-jie Hu Yi Guoqing Liu College of Information and Engineering Wuhan University of Science and Technology

ISBN: (纸本)9781538629185

In the indoor video surveillance system where the camera moves with the carrying equipment,the background and the target have different motion characteristics.Extracting and matching the background feature is the key to segment the background and foreground.For this reason,the background feature detection is of great significance.Aiming at the disadvantages of single feature based feature detection methods,a novel detection algorithm which combines both the features of corners and line segments is proposed.In the algorithm,the improved Harris algorithm and the Hough transform are used to roughly feature the corners and line segments respectively.Then,the distances from each selected corner to the line segments are calculated.In terms of the distances,the precise feature detection results are obtained.Finally,the NCC algorithm and RANSAC algorithm are used to bring the set of matching corners into the least square model to calculate the optimal parameter solution of affine transformation.Experimental results show that this algorithm has better performance in accuracy,real-time and robustness.

关键词： Video surveillance Motion background Feature matching Corner line segment

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Acta Mathematicae Applicatae Sinica 1995年第4期11卷 359-368页

作者：徐寅峰周电 Xi\'an Jiaotong University the University of North Carolina at Charlotte

Given a planar point set S, a triangulation of S is a maximal set of non-intersecting line segments connecting the points. The minimnm weight triangulation problem is to find a triangulation of S such that the sum of the lengths of the line segments in it is the smallest. No polynomial time algorithm is known to produce the optimal or even a constant approximation of the optimal solution, and it is also unknown whether the problem is NP-hard. In this paper,we propose two improved heuristics, which triangulate a set of n points in a plane in O(n3) time and never do worse than the minimum spanning tree triangulation algorithm given by Lingas and the greedy spanning tree triangulation algorithm given by Heath and Pemmaraju. These two algorithms both produce an optimal triangulation if the points are the vertices of a convex polygon, and also do the same in some special cases.

关键词： line segment Point setS Polynomial Time Time Algorithm Minimum Span Tree