Research On Theory And Method Of Contour Change Detection Based On Similarity Measurement

Under the condition that the basic geospatial database of our country has been built,the rapid and efficient updating of geospatial data is becoming more and more important in national defense construction,national economy as well as daily life.Therefore,the update of basic geospatial data has become the significant challenge in current field of mapping and geographic information.Contour line is an important geospatial element,and its production and update is necessary for the update of basic geospatial data.The current method of contour update has problems such as unnecessary update,inconsistency in precision,and large workload of post-processing.Therefore,realizing partial update for change region through change detection of contour lines has become an urgent need of improving the contour line update efficiency and accuracy.This paper focuses on the principle and method of local variation update of contour data based on high precision DEM data.Firstly,the contour similarity hierarchy is built based on the spatial similarity theory,and the contour change detection strategy is developed.High precision DEM used as reference data is generated from remote sensing imagery by geometric positioning.Then,the geometric and topological similarity measure method of contour lines are studied.The morphological and structural differences between original data and the reference data are separately quantified.Finally,the change detection model is built based on the relationship and mechanism of geometric and topological features.The main objective of this study is to improve the update efficiency and precision for contour data in topographic maps by the satellite remote sensing data,and the joint processing of the contour change detection based on the similarity,which could be considered as the reference for the basic geospatial data updating.The primary missions and innovations are shown as follows.1.The spatial similarity theory is firstly introduced to study the impact elements for the contour data similarity and differences combined the spatial features.The contour data variation detection model is then constructed based on the feature of similar hierarchies,and the local variation detection strategy for contour data is formulated according to the spatial similarity theory,which could be considered as the theoretical support for contour variation detection.2.Research on improving the geometric positioning accuracy and systematic error correction of remote sensing images as well as obtaining high-precision DEM data.The Errors-in-variables model is introduced to describe the observation vector of the parameter estimation equation in the rational function model and the error in the coefficient matrix.On the basis of that model and the regularized total least squares method,the calculation method of the systematic error parameter in the rational function model is derived.The correctness and rationality of the derivation method are verified by experiments,and the related DEM is generated using obtained parameters.3.The geometric similarity measure method of contour line features considering morphological features is studied.For the problem of measurement in the dense or highly variable contour area using the geometric similarity measure method based on Euclidean space distance or area,the geometric similarity measure method considering the morphological features is proposed.The feature descriptor function is used to transform the two-dimensional node sequence into a onedimensional geometric feature description sequence,and the dynamic programming method is used to solve the longest common subsequence(LCS)among the feature description sequences.Subsequently,its length quantification could be used to solve the geometrical similarity of the linear features.The experimental results show that the proposed method effectively takes into account the geometrical features of the line features and has higher accuracy and operational efficiency than the existing methods.4.The topological similarity measure method of contour groups considering the topological structure is studied.As the method of statistical mean based on topological relationship is easy to generate measurement error in complex topological relationship measurement and regional topology change evaluation,a topological similarity measurement method considering regional structure features is proposed.Based on the contour topological tree,the topological difference between the contour groups is converted into the editing distance between the contour trees.By constructing the tree editing operation mode of the terrain change,the Zhang-Shasha algorithm is introduced to quantify the tree editing distance,and the topological similarity between contour groups is then solved by the tree editing based quantification.The experimental results show that the proposed method can effectively measure the similarity of topological structure between multisource and multi-scale contour groups.5.Study on the relationship,mechanism as well as the measurement method of contour groups in the local topographic variation detection.The overall local contour variation detection model is derived combined the proposed geometric feature and topological similarity measurement method.Put forward a method for automatically distributing weight coefficient of related influence factors,such as topology,shape and length.The experimental results show that this model could be available for detecting and analyzing the topological variation,as well as assisting in contour data renewal and fusion.6.On the basis of contour change detection using similarity measurement,the local variation renewals for the original contour data is carried out,and then perform the validity test as well as the consistency processing for the obtained updating data.For the sake of meeting the demand for the topographic renewal,a contour boundary optimized expression method for solving the problem of geometric and topological inconsistency in the updating boundary area is proposed,which is available to process the overlapped or intersected contours in that area.Finally,the research results of the thesis are applied into the application experimental for the local contour change detection and updating,and the validity and the reliability of the scheme are verified.