Research On Technology Of Digital City Automatic Reconstruction Based On Image

3D digital city is a systematic engineering concerning with multi subjects. Even thoughsome progresses have been made in theoretical research, it is still very difficult with regard toreal-time display and interactive manipulation on general computers. Therefore, for thedevelopment of information technology and the construction of intelligent city, it ismeaningful both theoretically and practically to explore the three dimensional automaticreconstruction method of cities.As far as the challenges in developing digital city is concerned, from imagereconstruction point of view, building reconstruction, DEM data reconstruction and buildinglocation are elaborated in this thesis. The work and results are expressed as follows.1. Reconstruct the building with single frame photography. The main research is thereconstruction method of sigle building. Firstly, an improved wavelet-ICA filter, which canextract the independent noise feature, is proposed. ICA is employed to regularize the signalfrom the wavelet dimensionality reduction of original image and serves to identify the noisefeature. Secondly, GA-PSO is incorporated to improve the Hough transform (HT)performance. Different strategies are introduced to reduce the computational effort, whichinclude efficient limitation of the search space and a hierarchical search method. A modifiedGA-PSO HT algorithm is developed to improve the performance and quality of reconstructionfor planar building recognition techniques. Thirdly, a method dealing with texture extractionand mapping form3D building image is also proposed, in which the3D-building isreconstructed based on the planar layout. Texture images are then extracted by mergingperspective and correcting input images. A new technique is studied and presented for thepurpose of removing perspective distortion and estimating the texture image color tocompensate for the light source color. The method is free of any intermediate process in3Dmeasurement.2. Reconstruct the city with stereo photograph. The main research is the reconstructionmethod of terrain and buildings. On the first place, according to the geometric properties oflinear pushbroom images, the epipolarity model of Linear CCD pushbroom images isanalyzed. A conjugate matching method is proposed on the basis of epipolar curve. The conjugate search algorithm, the correlation region solution and match strategy are solved withthe conjugate matching method. The advantage of this method is validated with experiments.Then features of the building are extracted with proposed Fuzzy threshold method. Hopfieldneural stereo matching method is set up and used to initialize classical matching problems.The proposed Hopfield neural stereo matching method improves matching rate and decreaseambiguities simultaneously. On the third place, the shortcomings of existing task schedulingalgorithms are analyzed, and a new efficient heuristic task scheduling algorithm, namely,HCDDSL is proposed. Through HCDDSL, the result of task schedule may be optimizedeffectively, and the time span of all tasks is also reduced.3. The model recognition and locating are accomplished with the features. The mainresearch is the identification and location method for building in large scene picture. At first,the wavelet transform method is utilized to process the edge extraction. The edge feature ofthe target is extracted through proposed method. Different kinds of targets detection can berealized with multi-level wavelet properties. Secondly, a new3D target recognition algorithmis proposed based on geometrically invariant relationships. The algorithm employs a cameramodel for projective image formation and the projection parameters constraints are analyzed.Besides, two invariant relationships are utilized to complete the target recognition withview-invariant object. Finally, an energy-based estimation algorithm uniting motion and viewdisparity is proposed on the basis of two energy models, which are the joint estimation modeland the simultaneous joint estimation model. The initial disparity of the current frame iscomputed with the difference between side-to-side motion and previous frame.