Applications in engineering manufacture, such as dimensional inspection, often require triangulat... more Applications in engineering manufacture, such as dimensional inspection, often require triangulation of large sets of measured 3D data. The CAD models of relevant complex parts are usually defined using trimmed NURBS (non-uniform rational B-spline). With such situations in mind, the paper proposes a new triangulation procedure which achieves high efficiency and robustness by utilising the CAD model as an available
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 1997
Accurate dimensional inspection and error analysis of free-form surfaces requires accurate regist... more Accurate dimensional inspection and error analysis of free-form surfaces requires accurate registration of the component in hand. Registration of surfaces defined as non-uniform rational B-splines (NURBS) has been realized through an implementation of the iterative closest point method (ICP). The paper presents performance analysis of the ICP registration method using Monte Carlo simulation. A large number of simulations were performed on an example of a precision engineering component, an aero-engine turbine blade, which was judged to possess a useful combination of geometric characteristics such that the results of the analysis had generic significance. Data sets were obtained through CAD (computer aided design)-based inspection. Confidence intervals for estimated transformation parameters, maximum error between a measured point and the nominal surface (which is extremely important for inspection) mean error and several other performance criteria are presented. The influence of sh...
Proceedings of 3rd IEEE International Conference on Image Processing, 1996
Registration of a rigid body is an essential step in many machine vision tasks. This paper presen... more Registration of a rigid body is an essential step in many machine vision tasks. This paper presents performance analysis of the iterative closest point method implemented for dimensional inspection of free form surfaces where the set of measured points is registered to a NURBS model. The results were obtained through Monte Carlo simulation. A large number of experiments were performed
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 2001
Probe radius compensation is necessary in metrology applications that employ contact probes, but ... more Probe radius compensation is necessary in metrology applications that employ contact probes, but it can be a significant source of systematic measurement errors when dealing with free-form part geometry. The paper presents implementation and performance analysis of a proposed new compensation technique based on the nominal computer aided design (CAD) model, which is assumed to be defined using non-uniform rational B-splines (NURBS). Errors associated with the conventional compensation approach are assessed on the basis of experiments using a modern coordinate measuring machine (CMM), providing clear motivation for this work. The proposed method consists of a number of steps, including measurement, generation of offset nominal surfaces, registration, surface fitting, data smoothing and calculation of compensating offsets. Critical steps include registration and NURBS surface fitting and their implementation is presented. Simulation studies are used to analyse the registration accurac...
The International Journal of Advanced Manufacturing Technology, 2000
... can be seen that no direct connection between global applications and the LIM is allowed. ...... more ... can be seen that no direct connection between global applications and the LIM is allowed. ... So all these distributed data can arrive at the GIM for the application before being ... all distributed applications with IDL interfaces regardless of their platforms and program-ming languages ...
The paper presents an implementation of free-form surface registration in relation to inspection ... more The paper presents an implementation of free-form surface registration in relation to inspection of engineering components, defined as NURBS. Registration is principally performed through the Iterative Closest Point (ICP) method. The time-critical step in ICP was found to be the determination of the closest points on NURBS to a given point in space. Significant speed improvements were achieved through the
Applications in engineering manufacture, such as dimensional inspection, often require triangulat... more Applications in engineering manufacture, such as dimensional inspection, often require triangulation of large sets of measured 3D data. The CAD models of relevant complex parts are usually defined using trimmed NURBS (non-uniform rational B-spline). With such situations in mind, the paper proposes a new triangulation procedure which achieves high efficiency and robustness by utilising the CAD model as an available
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 1997
Accurate dimensional inspection and error analysis of free-form surfaces requires accurate regist... more Accurate dimensional inspection and error analysis of free-form surfaces requires accurate registration of the component in hand. Registration of surfaces defined as non-uniform rational B-splines (NURBS) has been realized through an implementation of the iterative closest point method (ICP). The paper presents performance analysis of the ICP registration method using Monte Carlo simulation. A large number of simulations were performed on an example of a precision engineering component, an aero-engine turbine blade, which was judged to possess a useful combination of geometric characteristics such that the results of the analysis had generic significance. Data sets were obtained through CAD (computer aided design)-based inspection. Confidence intervals for estimated transformation parameters, maximum error between a measured point and the nominal surface (which is extremely important for inspection) mean error and several other performance criteria are presented. The influence of sh...
Proceedings of 3rd IEEE International Conference on Image Processing, 1996
Registration of a rigid body is an essential step in many machine vision tasks. This paper presen... more Registration of a rigid body is an essential step in many machine vision tasks. This paper presents performance analysis of the iterative closest point method implemented for dimensional inspection of free form surfaces where the set of measured points is registered to a NURBS model. The results were obtained through Monte Carlo simulation. A large number of experiments were performed
Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 2001
Probe radius compensation is necessary in metrology applications that employ contact probes, but ... more Probe radius compensation is necessary in metrology applications that employ contact probes, but it can be a significant source of systematic measurement errors when dealing with free-form part geometry. The paper presents implementation and performance analysis of a proposed new compensation technique based on the nominal computer aided design (CAD) model, which is assumed to be defined using non-uniform rational B-splines (NURBS). Errors associated with the conventional compensation approach are assessed on the basis of experiments using a modern coordinate measuring machine (CMM), providing clear motivation for this work. The proposed method consists of a number of steps, including measurement, generation of offset nominal surfaces, registration, surface fitting, data smoothing and calculation of compensating offsets. Critical steps include registration and NURBS surface fitting and their implementation is presented. Simulation studies are used to analyse the registration accurac...
The International Journal of Advanced Manufacturing Technology, 2000
... can be seen that no direct connection between global applications and the LIM is allowed. ...... more ... can be seen that no direct connection between global applications and the LIM is allowed. ... So all these distributed data can arrive at the GIM for the application before being ... all distributed applications with IDL interfaces regardless of their platforms and program-ming languages ...
The paper presents an implementation of free-form surface registration in relation to inspection ... more The paper presents an implementation of free-form surface registration in relation to inspection of engineering components, defined as NURBS. Registration is principally performed through the Iterative Closest Point (ICP) method. The time-critical step in ICP was found to be the determination of the closest points on NURBS to a given point in space. Significant speed improvements were achieved through the
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