Surface Reconstruction Process Research Articles

Breakthroughs in hard X-ray diffraction: towards a multiscale science approach in heterogeneous catalysis.

Breakthroughs in hard X-ray diffraction: towards a multiscale science approach in heterogeneous catalysis.

In situ STM studies of electrochemically polished Cd(0001) electrode in aqueous electrolyte solutions

The in situ STM studies of electrochemically polished Cd(0001) electrode in the H3PO4 aqueous solution have been performed under negative electrode potentials from −1.4 to −0.9V (versus Ag|AgCl in sat. KCl aqueous solution) in the 0.1M Na2SO4+1×10−5M H2SO4 aqueous solution. The atomic resolution parameters of Cd(0001) surface have been calculated. The in situ STM data show that there are no surface reconstruction processes and the surface structure of electrochemically polished Cd(0001) is stable within the potential region investigated.

Examining the effects of self-assembled monolayers on nanoporous gold based amperometric glucose biosensors

Nanoporous gold (NPG) based biosensors have been constructed by covalently immobilizing glucose oxidase (GOx) onto self-assembled monolayers (SAMs). With p-benzoquinone (BQ) as a mediator, diffusion behavior and amperometric biosensor performance are evaluated by electrochemical characterization. The enzyme modified electrodes are demonstrated to show a thickness-sensitive behavior. Compared with planar polycrystalline gold, the unique porous structure of NPG has also been characterized via an electrochemical surface reconstruction process. Single-crystal gold-like electrochemical behavior on NPG and a comprehensive understanding of its impacts on sensor performance have been proposed.

Processing Research Based on Multi-scale Analysis of Image Segmentation Surface Reconstruction Algorithm

In order to improve the cutting surface reconstruction algorithm, which needs a large amount of calculation, and to obtain higher quality of reconstruction surface, processing research of image segmentation surface reconstruction algorithm is proposed based on multi-scale analysis. Through the analysis of the surface reconstruction algorithm and process steps based on multi-scale graph cut, the energy function is constructed, and maps it to the 3 d figure of edge and vertex weights, so as to construct a graph cut extraction matrix and interpolation matrix. In order to further verify the performance of the algorithm, comparative analyses of the experiment tests of the triangle network was implemented through c + +. The results show that under the same conditions, this algorithm’s computation speed is faster than the narrow band graph cut algorithm, its effect of rebuilding the figure cut will be better, and can get reconstruction surface of higher quality.

Efficient boundary surface reconstruction from heterogeneous volumetric data via tri-prism decomposition

We propose a novel and efficient approach for extracting the boundary surfaces from heterogeneous volumetric data in one pass. Each homogeneous material component is surrounded by a boundary surface, which is composed of piecewise 2-manifold meshes. The key idea is to subdivide each cubical voxel into two tri-prism voxels and to construct the boundary surfaces in a dimension-ascending (DA) way, i.e., from points to lines and then to faces. The extracted boundary surfaces can fully isolate the homogeneous material components, and the information on intersections between boundary surfaces can be explicitly retrieved. The surface reconstruction process can be accomplished efficiently by adopting a case table. The proposed approach is independent of the number of material types employed. Additionally, a new case index encoding approach is proposed to encode all possible cases in a heterogeneous tri-prism voxel that can verify the proposed DA approach in an exhaustive enumeration manner. The experimental results demonstrate that our approach can accurately and efficiently generate a boundary representation of heterogeneous volumetric data.

A Technology to Multi-Resolution Surface Reconstruction

An approach is presented based on scattered data points subdivision surfaces to achieve multi-resolution surface reconstruction techniques. In the surface reconstruction process, based on gray-scale image edge detection ideological eigenvalues scattered data analysis, these features will generate texture characteristic curve values tessellation, thus forming a multi-resolution mesh model structure; After testing, the technology is not only surface reconstruction short time, while the constructed subdivision surfaces can reflect the characteristics of the original details of the data.

3D surface reconstruction of stereo endoscopic images for minimally invasive surgery

Surface to surface registration of MR and endoscopic images is the key to MR and endoscopic image fusion, which will provide the surgeon with better 3D context of the surgical site in minimally invasive procedures. However, accurate reconstruction of 3D surface from stereo endoscopic images is still a challenging task especially for the surgical site with few features. In this paper, we propose a new method to reconstruct 3D surface from stereo endoscopic images. We project a gridline light pattern onto the surgical site and then use a stereo endoscope to acquire two stereo images. The major steps in the surface reconstruction process include 1) applying an automatic method of detecting region of interest, 2) applying an image intensity correction algorithm, and 3) applying a novel automatic method to match the intersection points of the gridline pattern. We have validated our proposed technique on a liver phantom and compared our method with an existing method of similar scope. Our experiment results show that our method outperforms the existing method in terms of correct matching rate (98% vs. 47%) which is an indicator of the surface reconstruction accuracy. The proposed technique has the potential to be used in clinical practice to improve image guidance in endoscope based minimally invasive procedures. This technique may also be applied to the endoscopic procedures of other organs in the abdomen, chest cavity and pelvis such as kidneys and lungs.

A geometrical approach for surface reconstruction by means of radial basis functions with compact support

Recently in the community of computer vision related with the surface reconstruction processes of free-form objects there has been a growing trend in the use of interpolation techniques. In this area the radial basis functions interpolator can produce three-dimensional models with high levels of precision, high flexibility to reproduce complex shapes and a high tolerance to noise level. The radial basis functions used for data interpolation need to estimate a set of parameters. This work shows a approach to estimation of those parameters based on the surface geometric characteristics, these are both centers and support ratio. The approach results are shown mean by interpolation of real objects range data.

Inspection of freeform surfaces considering uncertainties in measurement, localization and surface reconstruction

Inspection of a manufactured freeform surface can be conducted by building its surface model and comparing this manufactured surface model with the ideal design surface model and its tolerance requirement. The manufactured freeform surface model is usually achieved by obtaining measurement points on the manufactured surface, transforming these measurement points from the measurement coordinate system to the design coordinate system through localization, and reconstructing the surface model using the localized measurement points. In this research, a method was developed to estimate the locations and their variances of any selected points on the reconstructed freeform surface considering different sources of uncertainties in measurement, localization and surface reconstruction processes. In this method, first locations and variances of the localized measurement points are calculated considering uncertainties of the measurement points and uncertainties introduced in the localization processes. Then locations and variances of points on the reconstructed freeform surface are obtained considering uncertainties of the localized measurement points and uncertainties introduced in the freeform surface reconstruction process. Two case studies were developed to demonstrate how these three different uncertainty sources influence the quality of the reconstructed freeform curve and freeform surface in inspection.

The Helmet Reverse Forming and Static Characteristic Analysis

In order to solve irregular product surface quality is difficult to test problems, this paper combined reverse engineering with finite element analysis related technologies, good results have been achieved. Selected the helmet as the research object, introduced the reverse engineering and finite element analysis of the basic methods and ideas. First through the 3D laser scanner for safety helmet surface point cloud data, the data conducted the pretreatment in the Imageware software, and then in UG finished surface reconstruction and materialization process, finally guided the reverse forming helmet entity into Ansys Workbench software to carry on the finite element analysis, through the generation of stress and deformation analysis nephogram to test the sample quality.

Dynamic Corneal Surface Mapping with Electronic Speckle Pattern Interferometry

In view of the fast advancement in ophthalmic technology and corneal surgery, there is a strong need for the comprehensive mapping and characterization techniques for corneal surface. Optical methods with precision non-contact approaches have been found to be very useful for such bio measurements. Along with the normal mapping approaches, elasticity of corneal surface has an important role in its characterization and needs to be appropriately measured or estimated for broader diagnostics and better prospective surgical results, as it has important role in the post-op corneal surface reconstruction process. Use of normal corneal topographic devices is insufficient for any intricate analysis since these devices operate at relatively moderate resolution. In the given experiment, Pulsed Electronic Speckle Pattern Interferometry has been utilized along with an excitation mechanism to measure the dynamic response of the sample cornea. A Pulsed ESPI device has been chosen for the study because of its micron-level resolution and other advantages in real-time deformation analysis. A bovine cornea has been used as a sample in the subject experiment. The dynamic response has been taken on a chart recorder and it is observed that it does show a marked deformation at a specific excitation frequency, which may be taken as a characteristic elasticity parameter for the surface of that corneal sample. It was seen that outside resonance conditions the bovine cornea was not that much deformed. Through this study, the resonance frequency and the corresponding corneal deformations are mapped and plotted in real time. In these experiments, data was acquired and processed by FRAMES plus computer analysis system. With some analysis of the results, this technique can help us to refine a more detailed corneal surface mathematical model and some preliminary work was done on this. Such modelling enhancements may be useful for finer ablative surgery planning. After further experimentation, this technique can possibly be developed for in-vivo experiments on animals and humans and then may prospectively be matured for future clinical usage.

3D-based reconstruction using growing neural gas landmark: application to rapid prototyping in shoe last manufacturing

Customizing shoe manufacturing is one of the great challenges in the footwear industry. It is a production model change where design adopts not only the main role, but also the main bottleneck. It is therefore necessary to accelerate this process by improving the accuracy of current methods. Rapid prototyping techniques are based on the reuse of manufactured footwear lasts so that they can be modified with CAD systems leading rapidly to new shoe models. In this work, we present a shoe last fast reconstruction method that fits current design and manufacturing processes. The method is based on the scanning of shoe last obtaining sections and establishing a fixed number of landmarks onto those sections to reconstruct the shoe last 3D surface. Automated landmark extraction is accomplished through the use of the self-organizing network, the growing neural gas (GNG), which is able to topographically map the low dimensionality of the network to the high dimensionality of the contour manifold without requiring a priori knowledge of the input space structure. Moreover, our GNG landmark method is tolerant to noise and eliminates outliers. Our method accelerates up to 12 times the surface reconstruction and filtering processes used by the current shoe last design software. The proposed method offers higher accuracy compared with methods with similar efficiency as voxel grid.

Prediction of surface reconstruction uncertainties for freeform surface inspection

A method is introduced to predict uncertainties of the B-spline freeform surfaces that are reconstructed from the measurement points for inspection of freeform surfaces. The uncertainties of a reconstructed B-spline surface are modeled by variances of coordinates of points on this freeform surface. Prediction of the uncertainty at any location on the reconstructed B-spline surface is carried out in two steps: (1) estimation of variances of the B-spline surface’s control points introduced by the surface reconstruction process, and (2) propagation of the variances from the control points to the points on the B-spline freeform surface. In this research, the variances of the control points of the reconstructed B-spline surface in all three directions are considered to improve the accuracy of uncertainty prediction in the regions with significant changes of geometric shapes. Both the errors and uncertainties at different locations on the reconstructed surface are considered in freeform surface inspection to compare the manufactured surface against the design surface and its tolerance. The developed method has been applied to two case studies to demonstrate its effectiveness.

In situ STM studies of Sb(111) electrodes in aqueous electrolyte solutions

The in situ STM studies of Sb(111), which was cleaved at the temperature of liquid nitrogen inside the glove box, and of Sb(111), which was electrochemically polished in the KI+HCl aqueous solution, have been performed under negative polarizations from −0.8 to −0.15V (versus Ag|AgCl in sat. KCl aqueous solution) in the 0.5M Na2SO4+0.0003M H2SO4 aqueous solution. The atomic resolution has been achieved. The in situ STM data show that there are no quick surface reconstruction processes and the surface structure of cleaved and electrochemically polished Sb(111) is stable within the potential region investigated, similarly for Bi(111) single crystal electrode, previously studied [S. Kallip, E. Lust, Electrochem. Comm. 7 (2005) 863].

Lifting of the [formula omitted] surface reconstruction of Au(1 1 1) as a sensitive probe to monitor adsorption of cyclodextrin and its complexes in halide solutions

Stabilization of the (3×22) reconstruction of Au(111) in halide solutions by adsorbed, uncharged organic molecules was investigated using cyclic voltammetry. In aqueous solutions containing either iodide, bromide, or chloride, the presence of α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), or a ferrocene inclusion complex of the latter (Fc·β-CD) was found to shift the potential of the (3×22) to (1×1) transition positive by several tens of mV. This shift is explained by the inhibition of halide adsorption due to the need to displace adsorbed cyclodextrin species. The size of the shift follows the trend in the strength of interaction between the three halides and the Au surface. Changes to the CV shapes suggest an influence of the cyclodextrins on both the thermodynamics and kinetics of the reconstruction lifting event. Differences observed in CVs recorded with the three cyclodextrin adsorbates also demonstrate the utility of the potential dependent surface reconstruction processes of Au(111) as a probe of adsorbed species. Each halide/cyclodextrin combination was further examined by perturbing the electrode surface with potential cycling and subsequently recording CVs to monitor the recovery of the surface to an equilibrium state.

Exploring the kinetics of switchable polymer surfaces with dynamic tensiometry

Switchable polymer multilayer coatings consisting of poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA) were prepared via Layer-by-Layer (LbL) assembly and post-functionalized with poly(ethylene glycol methyl ether) (PEG). This resulted in a soft polar coating that reversibly and repeatedly rearranges from hydrophobic to hydrophilic (or vice versa) when contacted with water (or air). Goniometry is used to quantify the forward surface rearrangement in the form of transient measurements of the water contact angle. By examining the time evolution of the water contact angle at various temperatures, the apparent activation energy for the forward surface rearrangement (Ea,f) can be determined. Further insight can be gained into the kinetics of this surface reconstruction process by utilizing dynamic tensiometry to measure the evolution in the contact angle of a liquid meniscus at several rates and temperatures as it advances or recedes over the multilayer films. A simple first-order thermally-activated rate process is shown to describe the forward and reverse surface reconstruction and enables the shape of the measured tensiometric force curves during repeated immersion and emersion to be predicted quantitatively. Using this model we show that the character of this switchable surface coating can appear to be hydrophobic or hydrophilic depending on a single dimensionless parameter which incorporates the characteristic time-scale for temperature-dependent surface rearrangement, the speed of immersion and the capillary length of the liquid meniscus.

Application Study on Reverse Design Method in Tobacco Heights Department of Tractor Panel

Reverse design of the flue-cured tobacco Heights Department of tractor panel has been designed, using reverse engineering software, 3D laser scanning equipment and electron microscopy equipment, after the collected data such as pre-processing and surface reconstruction process, to get a tractor panel of tobacco Heights Department. The initial structural model, and associated structural re-design, research results show that the rapid establishment of a new product manufacturing system to improve new product quality and development efficiency has important practical significance.

Surface chemistry of bulk nanocrystalline pure iron and electrochemistry study in gas-flow physiological saline

Conventional microcrystalline pure iron (MC-Fe) becomes a new candidate as biodegradable metals, which has the insufficient physical feature and inferior biodegradation behavior. Novel bulk nanocrystalline pure iron (NC-Fe) was fabricated via equal channel angular pressing technique in the present work to overcome these problems. The contact angle test with water and glycerol droplets shows a smaller angle (though >90°) of NC-Fe than that of MC-Fe, which implies a lower surface energy of NC-Fe. The surface roughness of NC-Fe increased greatly than that of MC-Fe. A further comparative study of corrosion and electrochemistry performance between NC-Fe and its original MC-Fe was investigated in physiological saline with different dissolved oxygen concentration, aiming to in vitro simulate the corrosion process of coronary stent occurred in physiological environment. The electrochemical impedance spectra analysis and anodic polarization measurements indicated that the NC-Fe exhibited higher corrosion resistance than that of the MC-Fe; meanwhile obvious enhanced corrosion resistance with the decrement of dissolved oxygen concentration was observed. Related equivalent circuit model and surface reconstruction process were further discussed, and the degradation mechanism of the MC-Fe and NC-Fe were finally established.

SURFACE RECONSTRUCTION FROM SCATTERED POINT DATA ON OCTREE

In this paper, we propose a very efficient method which reconstructs the high resolution surface from a set of unorganized points. Our method is based on the level set method using adaptive octree. We start with the surface reconstruction model proposed in [20]. In [20], they introduced a very fast and efficient method which is different from the previous methods using the level set method. Most existing methods[21, 22] employed the time evolving process from an initial surface to point cloud. But in [20], they considered the surface reconstruction process as an elliptic problem in the narrow band including point cloud. So they could obtain very speedy method because they didn't have to limit the time evolution step by the finite speed of propagation. However, they implemented that model just on the uniform grid. So they still have the weakness that it needs so much memories because of being fulfilled only on the uniform grid. Their algorithm basically solves a large linear system of which size is the same as the number of the grid in a narrow band. Besides, it is not easy to make the width of band narrow enough since the decision of band width depends on the distribution of point data. After all, as far as it is implemented on the uniform grid, it is almost impossible to generate the surface on the high resolution because the memory requirement increases geometrically. We resolve it by adapting octree data structure[12, 11] to our problem and by introducing a new redistancing algorithm which is different from the existing one[19].

Reverse Engineering in the Design of a Plastic Part

Reverse engineering has been widely recognized as a central step in a product cycle of designing and manufacturing. However, major problems with current reverse engineering technology are the inefficient surface reconstruction process, lack of digitizing accuracy control in the data digitization process, and bottlenecks resulted from huge amounts of digitized surface points in the surface modeling process. Moreover, under this limitation, modern concurrent engineering concepts are difficult to be applied to obtain optimal product process. This paper presents a case study on the reverse designing of a plastic part. The study applies a developed reverse engineering approach to reconstruct surface--a series of advanced algorithms, including segmentation, simplification, extraction, fitting curves and reconstruction surface. Two orthogonal curves, which are fitted from the digitized points, are taken as base curves of a ruled surface patch. All surface patches are merged into a whole surface by trimming and chamfering. A CAD model is constructed based on the whole surface. The approach integrates surface digitizing and modeling processes of a plastic part into surface reconstruction process. Using the approach, accurate product CAD model can be efficiently generated and the product design cycle of plastic parts can be successfully linked.