Kinematical Methods for the Classification, Reconstruction, and Inspection of Surfaces

Introduction This contribution discusses recent progress in our investigation of reconstruction of geometric objects from point clouds such as laser scanner data. We rst focus on a class of simple surfaces, which includes surfaces of revolution, cylindrical surfaces, and helical surfaces. The basic idea behind the reconstruction process is to nd a motion which generates this surface. The algorithm works by tting a velocity vector eld to a given point cloud. This procedure is of a line-geometric nature and can be formulated as an approximation problem in line space. It basically amounts to solving a general eigenvalue problem. By locally applying this method we can reconstruct other types of surfaces as well | composite surfaces, and pipe or pro le surfaces. The second part of this addresses a geometric positioning problem, namely the optimal matching of a cloud of points (obtained by discrete measurements) to a CAD model. We further discuss related problems in Computer Vision a

Industrial geometry: Recent advances and applications in CAD

Industrial Geometry aims at unifying existing and developing new methods and algorithms for a variety of application areas with a strong geometric component. These include CAD, CAM, Geometric Modeling, Robotics, Computer Vision and Image Processing, Computer Graphics and Scientific Visualization. The methods are mainly taken from classical geometry, computational geometry, CAGD and various branches of applied and industrial mathematics. In this paper, Industrial Geometry is illustrated via the fruitful interplay of the areas indicated above in the context of novel solutions of CAD related, geometric optimization problems: approximation with general NURBS curves and surfaces, approximation with special surfaces for applications in architecture and manufacturing, and registration problems for industrial inspection and 3D model generation from measurement data.link_to_subscribed_fulltex

Industrial geometry: Recent advances and applications in CAD

Industrial Geometry aims at unifying existing and developing new methods and algorithms for a variety of application areas with a strong geometric component. These include CAD, CAM, Geometric Modelling, Robotics, Computer Vision and Image Processing, Computer Graphics and Scientific Visualization. In this paper, Industrial Geometry is illustrated via the fruitful interplay of the areas indicated above in the context of novel solutions of CAD related, geometric optimization problems involving distance functions: approximation with general B-spline curves and surfaces or with subdivision surfaces, approximation with special surfaces for applications in architecture or manufacturing, approximate conversion from implicit to parametric (NURBS) representation, and registration problems for industrial inspection and 3D model generation from measurement data. Moreover, we describe a 'feature sensitive' metric on surfaces, whose definition relies on the concept of an image manifold, introduced into Computer Vision and Image Processing by Kimmel, Malladi and Sochen. This metric is sensitive to features such as smoothed edges, which are characterized by a significant deviation of the two principal curvatures. We illustrate its applications at hand of feature sensitive curve design on surfaces and local neighborhood definition and region growing as an aid in the segmentation process for reverse engineering of geometric objects. © 2004 Elsevier Ltd. All rights reserved.link_to_subscribed_fulltex

The intracellular Ig fold: a robust protein scaffold for the engineering of molecular recognition

Item does not contain fulltextProtein scaffolds that support molecular recognition have multiple applications in biotechnology. Thus, protein frames with robust structural cores but adaptable surface loops are in continued demand. Recently, notable progress has been made in the characterization of Ig domains of intracellular origin--in particular, modular components of the titin myofilament. These Ig belong to the I(intermediate)-type, are remarkably stable, highly soluble and undemanding to produce in the cytoplasm of Escherichia coli. Using the Z1 domain from titin as representative, we show that the I-Ig fold tolerates the drastic diversification of its CD loop, constituting an effective peptide display system. We examine the stability of CD-loop-grafted Z1-peptide chimeras using differential scanning fluorimetry, Fourier transform infrared spectroscopy and nuclear magnetic resonance and demonstrate that the introduction of bioreactive affinity binders in this position does not compromise the structural integrity of the domain. Further, the binding efficiency of the exogenous peptide sequences in Z1 is analyzed using pull-down assays and isothermal titration calorimetry. We show that an internally grafted, affinity FLAG tag is functional within the context of the fold, interacting with the anti-FLAG M2 antibody in solution and in affinity gel. Together, these data reveal the potential of the intracellular Ig scaffold for targeted functionalization

On Surface Approximation using Developable Surfaces

We introduce a method for approximating a given surface by a developable surface. It will be either a G¹ surface consisting of pieces of cones or cylinders of revolution or a G r NURBS developable surface. Our algorithm will also deal properly with the problems of reverse engineering and produce robust approximation of given scattered data. The presented technique can be applied in computer aided manufacturing, e.g. in shipbuilding

On surface approximation using developable surfaces

We introduce a method for approximating a given surface by a developable surface. It will be either a G¹ surface consisting of pieces of cones or cylinders of revolution or a G r NURBS developable surface. Our algorithm will also deal properly with the problems of reverse engineering and produce robust approximation of given scattered data. The presented technique can be applied in computer aided manufacturing, e.g. in shipbuilding