We aim to formulate the recognition of a planes from a discrete point set as a nonlinear optimization problem, and we prove a uniqueness theorem for the solution of this problem. We deal with the supercover model in a...
详细信息
We aim to formulate the recognition of a planes from a discrete point set as a nonlinear optimization problem, and we prove a uniqueness theorem for the solution of this problem. We deal with the supercover model in a space for the expression of discrete planes. The algorithm achieves invertible data compression of digital objects, since the algorithm transforms a collection voxels to a collection of plane parameters, which classify the voxels.
Interactive 3d modeling is the process of building a 3d model of an object or a scene in real-time while the 3d (range) data is acquired. This is possible only if the computational complexity of all involved algorithm...
详细信息
Interactive 3d modeling is the process of building a 3d model of an object or a scene in real-time while the 3d (range) data is acquired. This is possible only if the computational complexity of all involved algorithms is linear with respect to the amount of data. We propose a new framework for 3d modeling where a complete modeling chain meets with this requirement. The framework is based on the use of vector fields as an implicit surface representation. Each modeling step, registration, surface reconstruction, geometric fusion, compression andvisualization is solved and explained using the vector fields without any intermediate representations. The proposed framework allows model reconstruction from any type of 3ddata, surface patches, curves, unorganized sets of points or a combination of these.
The human vision system can discriminate regions which differ up to the second order statistics only. A lot of malignant tumours have boundaries which are not visible to the human eye. We present an algorithm designed...
详细信息
The human vision system can discriminate regions which differ up to the second order statistics only. A lot of malignant tumours have boundaries which are not visible to the human eye. We present an algorithm designed to reveal "hidden" boundaries in grey level images, by computing gradients in higher order statistics of the data. We demonstrate it by applying it to the identification of possible "hidden" boundaries of gliomas as manifest themselves in MRI 3d scans.
The problem of virtual view creation has received increasing attention in recent years. Major current approaches are based on modified stereo vision systems. Recently the structure light measurement system based on di...
详细信息
The problem of virtual view creation has received increasing attention in recent years. Major current approaches are based on modified stereo vision systems. Recently the structure light measurement system based on digital light projection supported by special data coding andprocessing allow to rapid3d shape acquisition. Application of this technology to record3ddata has increased significantly the accuracy of reconstructed shape and simplifieddata manipulation process. In the paper the general concept of virtual reality system supported by data gathered by means of structure light projection is presented. The methodology of conversion of cloud of measurement points (x,y,z,R,G,B) into virtual reality environment is described. It is supported by implementation of a virtual camera concept, as the mean for interactive object visualization. The methodology of real time 3d object visualization based on its coding by means of specially formed contours and their B-spline approximation is presented. The applicability of the methodology has been shown on numerically generateddata which simulate performance of the measurement system. The total processing path was successfully tested.
A method for 3d model content-based search and retrieval based on the 3d Radon transform and a querying-by-3d-model approach, is presented. descriptors are extracted using the 3d Radon transform and applying a set of ...
详细信息
A method for 3d model content-based search and retrieval based on the 3d Radon transform and a querying-by-3d-model approach, is presented. descriptors are extracted using the 3d Radon transform and applying a set of functionals on the transform coefficients. Similarity measures are then created for the extracteddescriptors and introduced into a 3d model-matching algorithm. This results to a very fast and accurate matching method. Experiments were performed using two different databases and comparing the proposed method with others. Experimental results show that the proposed method can be used for 3d model search and retrieval in a highly efficient manner.
A method for modelling and visualizing human lungs using knowledge of lung anatomy and high resolution CT (HRCT) images is presented. The model consists of a symbolic description of lung anatomy and a 3d atlas. The 3d...
详细信息
A method for modelling and visualizing human lungs using knowledge of lung anatomy and high resolution CT (HRCT) images is presented. The model consists of a symbolic description of lung anatomy and a 3d atlas. The 3d atlas is constructed using HRCT volume data. A few anatomical landmarks are determined and are used to divide the lungs into anatomically anddiagnostically important regions. The landmarks and the lung regions enable accurate mapping of the model to patient data and enable the system to deal with image and human variability. The model can be displayed as a set of labelled axial slices and as a 3d model of the lungs. The 3dvisualization enables rotation and viewing of lung structures, lung features and lung regions from different angles.
A 3-dimensional (3d) object modeling technique with mesh simplification and refinement based resolution adjustment is proposed in this paper. Polygonal models which are widely utilized in the modeling of 3d objects ar...
详细信息
A 3-dimensional (3d) object modeling technique with mesh simplification and refinement based resolution adjustment is proposed in this paper. Polygonal models which are widely utilized in the modeling of 3d objects are taken as basis, making use of the polygonal structure and vertex coordinates for the display of 3d models. The amount of polygons and vertices of a model is proportional to the resolution as well as data quantity. In other words the resolution anddata increases with the number of polygons. In this paper, it is proposed to utilize resolution, and hence data amount, adjustable 3d modeling so that model resolution and transmitteddata amount can be regulated according to access constraints.
Hand-guided scanners allow for digitization by manually sweeping a laser beam over an object39;s surface. The result highly depends on the way the user handles the system and his ability to keep track of the parts o...
详细信息
Hand-guided scanners allow for digitization by manually sweeping a laser beam over an object's surface. The result highly depends on the way the user handles the system and his ability to keep track of the parts of the surface that are already scanned. processing andvisualizationduring data acquisition are helpful in this context. In this paper, we propose an online surface reconstruction algorithm for the visualization of the dLR scanner system data. The algorithm successively generates a triangle mesh by incrementally inserting 3d points. Point neighborhoods are used to limit the point density, to estimate the surface normal at the inserted point, and to locally retriangulate the mesh. A dynamic data structure for fast neighborhood search without restrictions to the amount of vertices or the object size and with low complexity is introduced. Finally, results with the hand-guided scanner system are presented.
A mesh conformation approach that makes use of deformable generic meshes has been applied to establishing correspondences between 3d shapes with missing data. Given a group of shapes with correspondences, we can build...
详细信息
A mesh conformation approach that makes use of deformable generic meshes has been applied to establishing correspondences between 3d shapes with missing data. Given a group of shapes with correspondences, we can build up a statistical shape model by applying principal component analysis (PCA). The conformation at first globally maps the generic mesh to the 3d shape based on manually located corresponding landmarks, and then locally deforms the generic mesh to clone the 3d shape. The local deformation is constrained by minimizing the energy of an elastic model. An algorithm was also embedded in the conformation process to fill missing surface data of the shapes. Using synthetic data, we demonstrate that the conformation preserves the configuration of the generic mesh and hence it helps to establish good correspondences for shape analysis. Case studies of the principal component analysis of shapes were presented to illustrate the successes and advantages of our approach.
We are developing a system for interactive modeling of real world scenes. The acquisition device consists of a video camera enhanced with an attached laser system. As the operator sweeps the scene, the device acquires...
详细信息
We are developing a system for interactive modeling of real world scenes. The acquisition device consists of a video camera enhanced with an attached laser system. As the operator sweeps the scene, the device acquires dense color and sparse depth frames that are registered and merged into a point-based model. The evolving model is rendered continually to provide immediate operator feedback. The interactive modeling pipeline runs at five frames per second. We model scenes in two modes based on their geometric complexity. Scenes that contain large smooth surfaces are modeled freehand; scenes that contain small uneven surfaces are modeled using a parallax-free camera bracket.
暂无评论