The recent needs of analysis and visualization of variable in time real 3d objects in many applications require development of new approach towards combining rapid3d shape acquisition and the methodology of data proc...
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The recent needs of analysis and visualization of variable in time real 3d objects in many applications require development of new approach towards combining rapid3d shape acquisition and the methodology of dataprocessing in order to perform visualization and analysis of real 3ddynamic objects. In this paper the general concept of visualization system of data gathered by means of optical 4d (x,y,z,t) shape measurement system is presented. The concept of a virtual camera, as the mean for interactive object visualization is introduced. The experimental results for processing of simulated and real variable in time 3d object are presented anddiscussed. The directions of future works focused on full implementation of the concept are introduced.
The usage of geometrical 3d-models enables humans to plan anddesign different aspects of indoor environments. This article describes the next-best-view planner for an autonomous 3d modelling robot using a 3d laser sc...
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ISBN:
(纸本)9781424421831
The usage of geometrical 3d-models enables humans to plan anddesign different aspects of indoor environments. This article describes the next-best-view planner for an autonomous 3d modelling robot using a 3d laser scanner. Besides the human user, the constructed3d-model can also be used by other autonomous robots for navigation and localization tasks. The process of building a 3d-model without any geometical pre-knowledge leads to a planning scheme which uses the 3ddata. This article copes with that problem by using and attributed 2d grid combined with an intelligent action planning scheme for indoor environments.
Membrane distillation (Md) [I] is a relatively new process that is being investigated world-wide as a low cost, energy saving alternative to conventional separation processes such as distillation and reverse osmosis (...
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ISBN:
(纸本)9780819466044
Membrane distillation (Md) [I] is a relatively new process that is being investigated world-wide as a low cost, energy saving alternative to conventional separation processes such as distillation and reverse osmosis (RO). This process offers some advantages compared to other more popular separation processes, such as working at room conditions (pressure and temperature);low-grade, waste and/or alternative energy sources such as solar and geothermal energy may be used;a very high level of rejection with inorganic solutions;small equipment can be employed, etc. The driving force in Md processes is the vapor pressure difference across the membrane. A temperature difference is imposed across the membrane, which results in a vapor pressure difference. The principal problem in this kind of system is the accurate measurement of the recipient volume change, especially at very low flows. A cathetometer, with up to 0,05 min resolution, is the instrument used to take these measurements, but the necessary human intervention makes this instrument not suitable for automated systems. In order to overcome this lack, a high resolution system is proposed, that makes automatic measurements of the volume of both recipients, cold and hot, at a rate of up to 10 times per second.
due to the increasing demand for high-quality ceramic crowns and bridges, the CAd/CAM-based production of dental restorations has been a subject of intensive research during the last fifteen years. A prerequisite for ...
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ISBN:
(纸本)0819457213
due to the increasing demand for high-quality ceramic crowns and bridges, the CAd/CAM-based production of dental restorations has been a subject of intensive research during the last fifteen years. A prerequisite for the efficient processing of the 3d measurement of prepared teeth with a minimal amount of user interaction is the automatic determination of the preparation line, which defines the sealing margin between the restoration and the prepared tooth. Current dental CAd/CAM systems mostly require the interactive definition of the preparation line by the user, at least by means of giving a number of start points. Previous approaches to the automatic extraction of the preparation line rely on single contour detection algorithms. In contrast, we use a combination of different contour detection algorithms to find several independent potential preparation lines from a height profile of the measureddata. The different algorithms (gradient-based, contour-based, and region-based) show their strengths and weaknesses in different clinical situations. A classifier consisting of three stages (range check, decision tree, support vector machine), which is trained by human experts with real-worlddata, finally decides which is the correct preparation line. In a test with 101 clinical preparations, a success rate of 92.0% has been achieved. Thus the combination of different contour detection algorithms yields a reliable method for the automatic extraction of the preparation line, which enables the setup of a turn-key dental CAd/CAM process chain with a minimal amount of interactive screen work.
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