Image output by computer is done row by row,the shortcoming of which is that we cannot know the topological relations between points at the image boundary.To obtain the closed boundary of the target from an image and ...Image output by computer is done row by row,the shortcoming of which is that we cannot know the topological relations between points at the image boundary.To obtain the closed boundary of the target from an image and turn points' row permutation of boundary into sequence permutation,an algorithm based on 4-connection relation of pixel points is proposed and the analysis of its correctness and complexity is given.Compared with classical operators and existing method,the single pixel boundary extracted from gray images by this algorithm is more complete and more distinct.Moreover,it has a lower time complexity and can eliminate the noise inside and outside the target area.The obtained sequence permutation of points is also conducive to follow-up image processing.展开更多
In order to extract the boundary of rural habitation, based on geographic name data and basic geographic information data, an extraction method that use polygon aggregation is raised, it can extract the boundary of th...In order to extract the boundary of rural habitation, based on geographic name data and basic geographic information data, an extraction method that use polygon aggregation is raised, it can extract the boundary of three levels of rural habitation consists of town, administrative village and nature village. The method first extracts the boundary of nature village by aggregating the resident polygon, then extracts the boundary of administrative village by aggregating the boundary of nature village, and last extracts the boundary of town by aggregating the boundary of administrative village. The related methods of extracting the boundary of those three levels rural habitation has been given in detail during the experiment with basic geographic information data and geographic name data. Experimental results show the method can be a reference for boundary extraction of rural habitation.展开更多
Height extraction for buildings is a fundamental step of 3D scene reconstruction in many virtual reality applications.In this paper,we propose an automatic method to extract the height of buildings in high resolution ...Height extraction for buildings is a fundamental step of 3D scene reconstruction in many virtual reality applications.In this paper,we propose an automatic method to extract the height of buildings in high resolution satellite imagery based on the length of shadow.Taking into account the limitation of traditional algorithms,we make use of the boundary information of a building to facilitate detecting and matching the shadow regions with higher accuracy.Then,we introduce a shadow-cast model to correct the shadow location in our system.The experimental result shows that when extracting the height of buildings from complex urban regions,our method has better accuracy.展开更多
With the development of advanced imaging technology, digital images are widely used. This paper proposes an automatic quadrilateral mesh generation algorithm for multi-colour imaged structures. It takes an original ar...With the development of advanced imaging technology, digital images are widely used. This paper proposes an automatic quadrilateral mesh generation algorithm for multi-colour imaged structures. It takes an original arbitrary digital image as an input for automatic quadrilateral mesh generation, this includes removing the noise, extracting and smoothing the boundary geometries between different colours, and automatic all-quad mesh generation with the above boundaries as constraints. An application example is provided to demonstrate the usefulness and effectiveness of the proposed approach.展开更多
Automation of rubber tree clone classification has inspired research into new methods of leaf feature extraction.In current practice,rubber clone inspectors has been using several leaf features to identify clone types...Automation of rubber tree clone classification has inspired research into new methods of leaf feature extraction.In current practice,rubber clone inspectors has been using several leaf features to identify clone types.One of the unique features of rubber tree leaf is palmate leaflets.This characteristic generates different leaflet positions,where the leaves are overlapping or separated.In this research,we propose keypoint extraction and line detection methods to extract shape and axil(angle between petioles)features of leaflet positions.The results of keypoint extraction methods,namely,SIFT,Harris,and FAST,were compared and discussed for shape feature extraction.Next,Hough transformation and boundary-tracing methods were compared to identify the suitable axil detection method.The evaluation result demonstrates the proper keypoint extraction method for shape context and the clear advantages of Hough Transformation in accuracy of angle detection.展开更多
基金Sponsored by the National Natural Science Foundation of China (60773044 )PLA General Armament Department Key Foundation(9140A26010308BQ0178)
文摘Image output by computer is done row by row,the shortcoming of which is that we cannot know the topological relations between points at the image boundary.To obtain the closed boundary of the target from an image and turn points' row permutation of boundary into sequence permutation,an algorithm based on 4-connection relation of pixel points is proposed and the analysis of its correctness and complexity is given.Compared with classical operators and existing method,the single pixel boundary extracted from gray images by this algorithm is more complete and more distinct.Moreover,it has a lower time complexity and can eliminate the noise inside and outside the target area.The obtained sequence permutation of points is also conducive to follow-up image processing.
文摘In order to extract the boundary of rural habitation, based on geographic name data and basic geographic information data, an extraction method that use polygon aggregation is raised, it can extract the boundary of three levels of rural habitation consists of town, administrative village and nature village. The method first extracts the boundary of nature village by aggregating the resident polygon, then extracts the boundary of administrative village by aggregating the boundary of nature village, and last extracts the boundary of town by aggregating the boundary of administrative village. The related methods of extracting the boundary of those three levels rural habitation has been given in detail during the experiment with basic geographic information data and geographic name data. Experimental results show the method can be a reference for boundary extraction of rural habitation.
基金Supported by National Natural Science Foundation of China(61232014,61421062,61472010)the National Key Technology R&D Program of China(2015BAK01B06)
文摘Height extraction for buildings is a fundamental step of 3D scene reconstruction in many virtual reality applications.In this paper,we propose an automatic method to extract the height of buildings in high resolution satellite imagery based on the length of shadow.Taking into account the limitation of traditional algorithms,we make use of the boundary information of a building to facilitate detecting and matching the shadow regions with higher accuracy.Then,we introduce a shadow-cast model to correct the shadow location in our system.The experimental result shows that when extracting the height of buildings from complex urban regions,our method has better accuracy.
基金supported by the Australian Research Council (ARC DP066620, LP0560932, and LX0989423)
文摘With the development of advanced imaging technology, digital images are widely used. This paper proposes an automatic quadrilateral mesh generation algorithm for multi-colour imaged structures. It takes an original arbitrary digital image as an input for automatic quadrilateral mesh generation, this includes removing the noise, extracting and smoothing the boundary geometries between different colours, and automatic all-quad mesh generation with the above boundaries as constraints. An application example is provided to demonstrate the usefulness and effectiveness of the proposed approach.
文摘Automation of rubber tree clone classification has inspired research into new methods of leaf feature extraction.In current practice,rubber clone inspectors has been using several leaf features to identify clone types.One of the unique features of rubber tree leaf is palmate leaflets.This characteristic generates different leaflet positions,where the leaves are overlapping or separated.In this research,we propose keypoint extraction and line detection methods to extract shape and axil(angle between petioles)features of leaflet positions.The results of keypoint extraction methods,namely,SIFT,Harris,and FAST,were compared and discussed for shape feature extraction.Next,Hough transformation and boundary-tracing methods were compared to identify the suitable axil detection method.The evaluation result demonstrates the proper keypoint extraction method for shape context and the clear advantages of Hough Transformation in accuracy of angle detection.
