A constraint-based parameterization technique for B-spline surfaces

Harmening, Corinna; Neuner, Hans

doi:10.1515/jag-2015-0003

Cited by 16 publications

(8 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are many approximation approaches for surface modeling based on 3D scattered points, including a polygonal model (e.g., a mesh by interpolation) or a regression model (e.g., a polynomial or B-spline surface) [30][31][32]. The difference of the concrete level among the gaps is typically not too significant owing to uniform casting and the concrete's fluidity.…”

Section: Algorithms For Surface Modellingmentioning

confidence: 99%

Monitoring of the Production Process of Graded Concrete Component Using Terrestrial Laser Scanning

et al. 2021

View full text Add to dashboard Cite

Accepting the ecological necessity of a drastic reduction of resource consumption and greenhouse gas emissions in the building industry, the Institute for Lightweight Structures and Conceptual Design (ILEK) at the University of Stuttgart is developing graded concrete components with integrated concrete hollow spheres. These components weigh a fraction of usual conventional components while exhibiting the same performance. Throughout the production process of a component, the positions of the hollow spheres and the level of the fresh concrete have to be monitored with high accuracy and in close to real-time, so that the quality and structural performance of the component can be guaranteed. In this contribution, effective solutions of multiple sphere detection and concrete surface modeling based on the technology of terrestrial laser scanning (TLS) during the casting process are proposed and realized by the Institute of Engineering Geodesy (IIGS). A complete monitoring concept is presented to acquire the point cloud data fast and with high-quality. The data processing method for multiple sphere segmentation based on the efficient combination of region growing and random sample consensus (RANSAC) exhibits great performance on computational efficiency and robustness. The feasibility and reliability of the proposed methods are verified and evaluated by an experiment monitoring the production of an exemplary graded concrete component. Some suggestions to improve the monitoring performance and relevant future work are given as well.

show abstract

Section: Algorithms For Surface Modellingmentioning

confidence: 99%

Monitoring of the Production Process of Graded Concrete Component Using Terrestrial Laser Scanning

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Free form surfaces like B-splines have been proven to be appropriate to model complex shapes like leaves (see for example Reference [14], Reference [33] or Reference [34]). The mathematical definition of such a B-spline surface is given by [35]:…”

Section: B-spline Based Leaf Modellingmentioning

confidence: 99%

“…Before being able to estimate the best-fitting B-spline, convenient surface parameters u and v have to be allocated to the observations. The parameterization in this paper is based on the iterative approach proposed in Reference [33]. The major strength of this parameterization approach is the definition of the surface parameter lines by means of the segments' boundary curves.…”

Section: B-spline Based Leaf Modellingmentioning

confidence: 99%

A Fully Automated Three-Stage Procedure for Spatio-Temporal Leaf Segmentation with Regard to the B-Spline-Based Phenotyping of Cucumber Plants

Harmening

Paffenholz

2020

Remote Sensing

Self Cite

View full text Add to dashboard Cite

Plant phenotyping deals with the metrological acquisition of plants in order to investigate the impact of environmental factors and a plant’s genotype on its appearance. Phenotyping methods that are used as standard in crop science are often invasive or even destructive. Due to the increase of automation within geodetic measurement systems and with the development of quasi-continuous measurement techniques, geodetic techniques are perfectly suitable for performing automated and non-invasive phenotyping and, hence, are an alternative to standard phenotyping methods. In this contribution, sequentially acquired point clouds of cucumber plants are used to determine the plants’ phenotypes in terms of their leaf areas. The focus of this contribution is on the spatio-temporal segmentation of the acquired point clouds, which automatically groups and tracks those sub point clouds that describe the same leaf. The application on example data sets reveals a successful segmentation of 93% of the leafs. Afterwards, the segmented leaves are approximated by means of B-spline surfaces, which provide the basis for the subsequent determination of the leaf areas. In order to validate the results, the determined leaf areas are compared to results obtained by means of standard methods used in crop science. The investigations reveal consistency of the results with maximal deviations in the determined leaf areas of up to 5%.

show abstract

“…Methods for determining appropriate knot vectors can be found in Schmitt and Neuner (2015) or Bureick et al (2016). Furthermore, convenient surface parameters u and v, locating the observations on the surface to be estimated, have to be a-priori allocated to the observations (Harmening and Neuner 2015).…”

Section: Introductionmentioning

confidence: 99%

A spatio-temporal deformation model for laser scanning point clouds

Harmening

Neuner

2020

J Geod

Self Cite

View full text Add to dashboard Cite

The establishment of the terrestrial laser scanner changed the analysis strategies in engineering geodesy from point-wise approaches to areal ones. During recent years, a multitude of developments regarding a laser scanner-based geometric state description were made. However, the areal deformation analysis still represents a challenge. In this paper, a spatio-temporal deformation model is developed, combining the estimation of B-spline surfaces with the stochastic modelling of deformations. The approach's main idea is to model the acquired measuring object by means of three parts, similar to a least squares collocation: a deterministic trend, representing the undistorted object, a stochastic signal, describing a locally homogeneous deformation process, and the measuring noise, accounting for uncertainties caused by the measuring process. Due to the stochastic modelling of the deformations in the form of distance-depending variograms, the challenge of defining identical points within two measuring epochs is overcome. Based on the geodetic datum defined by the initial trend surface, a pointto-surface-and a point-to-point-comparison of the acquired data sets is possible, resulting in interpretable and meaningful deformation metrics. Furthermore, following the basic ideas of a least squares collocation, the deformation model allows a time-related space-continuous description as well as a space-and time-continuous prediction of the deformation. The developed approach is validated using simulated data sets, and the respective results are analysed and compared with respect to nominal surfaces.

show abstract

A constraint-based parameterization technique for B-spline surfaces

Cited by 16 publications

References 6 publications

Monitoring of the Production Process of Graded Concrete Component Using Terrestrial Laser Scanning

Monitoring of the Production Process of Graded Concrete Component Using Terrestrial Laser Scanning

A Fully Automated Three-Stage Procedure for Spatio-Temporal Leaf Segmentation with Regard to the B-Spline-Based Phenotyping of Cucumber Plants

A spatio-temporal deformation model for laser scanning point clouds

Contact Info

Product

Resources

About