Shape Verification Research Articles

Similar object shape representation encoded in the inferolateral occipitotemporal cortex of sighted and early blind people.

We can sense an object's shape by vision or touch. Previous studies suggested that the inferolateral occipitotemporal cortex (ILOTC) implements supramodal shape representations as it responds more to seeing or touching objects than shapeless textures. However, such activation in the anterior portion of the ventral visual pathway could be due to the conceptual representation of an object or visual imagery triggered by touching an object. We addressed these possibilities by directly comparing shape and conceptual representations of objects in early blind (who lack visual experience/imagery) and sighted participants. We found that bilateral ILOTC in both groups showed stronger activation during a shape verification task than during a conceptual verification task made on the names of the same manmade objects. Moreover, the distributed activity in the ILOTC encoded shape similarity but not conceptual association among objects. Besides the ILOTC, we also found shape representation in both groups' bilateral ventral premotor cortices and intraparietal sulcus (IPS), a frontoparietal circuit relating to object grasping and haptic processing. In contrast, the conceptual verification task activated both groups' left perisylvian brain network relating to language processing and, interestingly, the cuneus in early blind participants only. The ILOTC had stronger functional connectivity to the frontoparietal circuit than to the left perisylvian network, forming a modular structure specialized in shape representation. Our results conclusively support that the ILOTC selectively implements shape representation independently of visual experience, and this unique functionality likely comes from its privileged connection to the frontoparietal haptic circuit.

Geometric Morphometric Analysis of the Human Hand Morphology Based on X-ray Imaging

Currently, in humans, the ratio of the index and ring fingers (2D:4D ratio) determines the morphological type of the hand: type 1 or radial (2D>4D), type 2 or neutral (2D=4D), type 3 or ulnar (2D<4D). However, the above differences do not allow for morphological verification of the hand shape as a whole.The aim of the study was to inspect the hand shapes depending on its morphology based on radiographical images with geometric morphometric methods.Material and methods. Geometric morphometry included an analysis of the right hand shape described by 20 landmarks located on digital radiographic images (anteriorposterior projection) in 50 males and 50 females. Each hand was classified according to whether the index finger was longer, equal to, or shorter than the ring finger by visual assessment.Results. The study revealed differences between the hand shapes in the transverse direction, namely, the hands of the ulnar type (U) were wider, while the hands of the radial type (R) were narrower. The hands of neutral shape, unlike the other two types, were more oval in shape. In average, the hand shape depended on the morphological type. The most pronounced shape transformations were due to the geometry of the metacarpal bones in the transverse direction, and due to the geometry of the II, IV and V fingers in the longitudinal direction. Intergroup differences in width were revealed between the group of hands of radial (R)-neutral (N) types and ulnar (U) type, and in length between the group of hands of radial (R)-ulnar (U) types and neutral (N) type. The allometry of the hand shape was minimal.Conclusion. The results of the study demonstrate the potentials of geometric morphometry for analysis of the human hand shapes and their variability depending on the morphological type.

Binocular fringe projection profilometry for the metrology of meter-scale optical surfaces

Demand for better quality, larger quantity, and size of astronomical telescopes from visible to radio frequencies is increasing. More rapid, efficient, and adaptable manufacturing processes are needed to support the needs of growing science and engineering communities in these fields. To aid the development and execution of these new processes, a flexible, accurate, and low-cost metrology system is needed. This paper outlines a variety of fringe projection profilometry (FPP) that has demonstrated high accuracy over large areas, making it a critical tool for manufacturing steel molds for forming primary reflectors and shape verification of the reflectors themselves used for radio astronomy.

Numerical simulation of thermal flow dynamics in oscillating laser welding of aluminum alloy

Oscillating laser beam has good welding characteristics due to excellent management of molten thermal flow, but the potential mechanism has been still unclear. In order to describe the influences of circular beam oscillation on the thermal flow dynamics accurately, a transient numerical model of oscillating laser welding of 6061 aluminum alloy was established, whose accuracy is higher than 88% according to the verification of weld shape. The results showed that the oscillating induced vortex was the domain driving force to change the melt flow, and the strengthened convective effect was the key factor to homogenize the temperature field. The convection effect increased about 10 times when the oscillation frequency (f) increased from 20 to 200 Hz, decreasing the average temperature gradient from 1518 to 1067 K/mm. With the increase of f, the melt flow gradually changed from the competition between vortex effect and convection to the dominated vortex effect. The whole pool presented as a stable vortex at a high-speed (≥0.18 m/s) when f ≥ 100 Hz, where the average velocity of molten pool was equivalent to that of the vortex. At given f, the vortex effect was weakened with the increase of oscillation radius because the proportion of oscillation-driven vortex in whole molten pool reduced. It limited the vortex effect within the front fluid region, and separated some small low-speed (≤0.06 m/s) vortexes in tail fluid region by the convection effect.

Using additive manufactured parametric models for wind tunnel test-based aerodynamic shape optimization

PurposeThe purpose of this paper is to propose a new approach of using additively manufactured parametric models in the wind tunnel test-based aerodynamic shape optimization (ASO) framework and to present its applicability test results obtained from a realistic aircraft design problem.Design/methodology/approachFor aircraft shape optimization, the following three methodologies were used. First, as a validation study, the possibility of using rapid prototyping (RP) model in the wind tunnel test was verified. Second, through the wind tunnel test-based ASO, the application and feasibility of the real fighter aircraft shape optimization were verified. A generic fighter configuration is parameterized to generate various test models using additive manufacturing. Wind tunnel tests are conducted to measure their stability criteria in high angle of attack (AOA). Finally, a computational fluid dynamics (CFD) study was performed and analysis procedures, costs and results compared to the wind tunnel test were compared and reviewed.FindingsRP technology can significantly reduce the time and cost of generating parametric wind tunnel models and can open up new possibilities for wind tunnel tests to be used in the rigorous aerodynamic design loop. There was a slight difference between the results of the RP model and the metallic model because of rigidity and surface roughness. However, the tendency of the aerodynamic characteristics was very similarly predictable. Although there are limitations to obtaining precise aerodynamic data, it is a suitable method to be applied to comparative studies on various shapes with large geo-metric changes in the early phase of design. The CFD analysis indicates that the wind tunnel-based ASO using the RP model shows the efficiency corresponding to the CFD shape optimization.Research limitations/implicationsThe RP parametric models may have various assembly error sources and rigidity problems. The proposed methodology may not be suitable for collecting the accurate aerodynamic database of a final design; rather, the methodology is more suitable to screen out many configurations having fairly large shape variation in the early stage of the design process.Practical implicationsThe wind tunnel test-based ASO can replace or supplement CFD-based ASO. In areas where CFD accuracy is low, such as high AOA flight characteristics, RP model wind tunnel-based ASO can be a research method that can secure both efficiency and accuracy advantages, providing ten times more effective in terms of cost and time. The wind tunnel test is used to obtain aerodynamic data at the final stage of shape design. It can be extended to a comparative study of several shapes in the early design phase. This procedure can be applied for both industrial level and educational aircraft design activities.Originality/valueThis study is the application to be applied as a parametric study on the whole aircraft, rather than using the RP model applying a simple partial control surface or configuration change of a part of the wing. The possibility of using the RP model was confirmed by comparing and verifying each other in a medium-sized wind tunnel using a relatively large RP model and a metallic model. It was verified that it can be applied in the shape design process, not the shape verification in the traditional design procedure, and a comparison with the CFD method was also performed. With further development and validation efforts, the new design framework may become an industrial standard for future aircraft development.

X-ray imaging and computed tomography for engineering applications

Abstract After an incremental development which took place over four decades, X-ray imaging has become an important tool for non-destructive testing and evaluation. Computed Tomography (CT) in particular beholds the power of determining the location of flaws and inclusions (e. g. in castings and composites) in three-dimensional object coordinates. Therefore, and thanks to a speed-up of the measurement, CT is now routinely considered for in-line inspection of electronics, castings and composites. When precision and not speed is important, Micro-CT (μCT) can be employed for Dimensional Measurements (DM, e. g. quality assurance and shape verification), as well as for in situ testing, and for characterizing micro-structures in metals and composites. Using appropriate image processing and analysis μCT can determine the local fibre orientation in composites, the granular morphology of battery cathodes or the inter-connectivity of certain phases in casting alloys. Today, the large variety of X-ray instruments and methods poses an application problem which requires experience and a lot of knowledge for deciding which technique applies best to the task at hand. Application-specific guidelines exist for X-ray radiography testing (RT) only, whereas standardization has been applied to CT, unfortunately leaving out high resolution sub μ CT, and nano-CT. For the latter exist an equally high number of NDT applications, however these instruments still necessitate a profound expertise. The task is to identify key industrial applications and push CT from system standardization to application specific automation.

Shape Verification Neural Network to Detection Personal Signature

This paper was concerned to study the standard features of the personal signature image. Independent features such as the area, height ,width, maximum vertical, maximum horizontal , and fractal dimension were taken to isomorphic of the original image . for more efficiently of this work the degree of complexity of image was studied and introduced as extra property of signature. Proposed algorithm was introduced for calculating the features of signature image. Many test image were taken for test this algorithm The executive appears that this algorithm is very sensitive and accurate when we have different and similar signature images. In this paper a method of verifying signatures using a technique of neural network is presented. static of various and dynamic of signature features are added in this model. Our proposal algorithm enhanced via neural network and Elman network. In our modified our method, many parameters of detection of digital images were added. These image parameters named as Width, Area, Maximum Vertical Projection, and Fractal Dimension. Fractal dimension is considered as the degree of complexity of the shape. Fractal dimension calculated the condensation of complexity of pure points of the shape without its boundaries. The dimension of the signature is varying between 1.0025 to 1.0584. Originally the signature is belonging to R2-Space (with dimension 2). The signature is considered as one of to the fractal shape. The fractal dimension is calculated by the Theorem of Boxes Squares Counting. The fractal signature dimension added an accuracy to our method for detection many signature shapes by the number of similarities in certain properties.

Verification in staged tile self-assembly

We prove the unique assembly and unique shape verification problems, benchmark measures of self-assembly model power, are $\mathrm{coNP}^{\mathrm{NP}}$-hard and contained in $\mathrm{PSPACE}$ (and in $\mathrm{\Pi}^\mathrm{P}_{2s}$ for staged systems with $s$ stages). En route, we prove that unique shape verification problem in the 2HAM is $\mathrm{coNP}^{\mathrm{NP}}$-complete.

A New Shape Matching-Based Verification Approach for QPFs

In this paper, a novel systematic method on the evaluation of quantitative precipitation forecast (QPF) errors from the perspective of rain-area shape verification is proposed. The method aims to improve the accuracy and efficiency of conventional station-based verifications (i.e., standard skill scores), which are insensitive to the biases of station location and rain-area shape and tend to ignore the continuity of precipitation in time and space. The method develops and combines the shape verification indexes, which include the overlap ratio of a forecasted rain-area (Ratio f ), the overlap ratio of the ground rain-area (Ratio t ), the Jaccard similarity coefficient between the shape of the QPF area, the shape of the ground rain-area (Jaccardshape), the critical success index (CSI) for the rain-area shape (CSIshape), the probability of detection (POD) for the rain-area shape (PODshape), and the false alarm ratio (FAR) for the rain-area shape (FARshape). This definition of QPF verification is applied to a rain event from 2016/08/02 00:30 to 2016/08/02 03:24 in the Guangdong Province. The decomposition of QPF errors into station-based errors and shape error components provides powerful insight into the effects of overall forecasting performance. The experimental results of this investigation show that the proposed method provides an opportunity to assess QPFs objectively and further promote advanced forecasting technologies from this perspective.

レーザかんな加工の最適初期き裂形状の検証

レーザかんな加工の最適初期き裂形状の検証

形状記憶合金の応力-歪曲線の測定とヒートエンジンに求められる要求性能の検証

形状記憶合金の応力-歪曲線の測定とヒートエンジンに求められる要求性能の検証

Shape Verification of Fused Deposition Modelling 3D Prints

In this article, the shape of fused deposition modelling (FDM) 3D printed testing objects is verified with 3D scanning technique. Leapfrog’s Creatr is used as a manufacturing device. The whole process of a materialization is explained – from preparation of a model to preparation of a printer. The study is meant to evaluate dimensional errors of printed parts and to give some advices on how to minimize them.

Development of Looper Shape Meter and Verification Test Results in Hot Rolling

The harder and thinner strips, such as high strength steel and so on, have been needed to be rolled. When the rolled strip becomes thinner and harder, the unstable state rolling and tail end pinching might occur and so the strip shape measurement during rolling is strongly required under the condition that tension is applied to the strip. Visual-type shape meter, which has been already used, could not measure the strip shape when tension is applied to the strip. Looper Shape Meter, hereinafter referred as LSM, has been developed which could measure the strip shape under the tension. LSM is installed between mill stands and consists of 7 segment rolls along the width direction and a segment roll has two torque meters. LSM could accurately measure the tension distribution along the width direction without hysteresis and is protected with purge air and internal cooling system against severe environment in hot rolling. In order to verify the performance of LSM, the verification test was carried out in laboratory and production line. As a result, enough durability and good results of measured strip shape are obtained. LSM is easily replaced with existing conventional looper and it is expected that LSM contributes to the stable rolling and improve the productivity of rolling.

Design, Analysis and Additive Manufacturing of Porous Structures for Biocompatible Micro-Scale Scaffolds

Advancements in the fields of biocompatible materials, manufacturing processes, computational methods and medicine have led to the emergence of a new field: micro-scale scaffolds for bone replacement and regeneration. Yet most such scaffolds produced today are characterized by very basic geometry, and their microstructure differs greatly from that of the actual tissue they are intended to replace. In this paper, we propose a novel approach for generating micro-scale scaffolds based on processing actual micro-CT images and then reconstructing a highly accurate geometrical model. This model is manufactured by means of a state-of-the-art 3D additive manufacturing process from biocompatible materials. At the micro-scale level, these scaffolds are very similar to the original tissue, thus interfacing better with the surrounding tissue and facilitating more efficient rehabilitation for the patient. Moreover, the approach facilitates the design and manufacture of patient-specific scaffolds which can copy patients’ exact structural and mechanical characteristics, taking into account their physical condition and medical history. By means of multi-resolution volumetric modeling methods, scaffold porosity can also be adapted according to specific mechanical requirements. The process of designing and manufacturing micro-scale scaffolds involves five major stages: (a) building a volumetric multi-resolution model from micro-CT images; (b) generation of surface geometric model in STL format; (c) additive manufacturing of the scaffold; (d) scaffold shape verification relative to the geometric design; and (e) verification of mechanical properties through finite element analysis. In this research, all the proposed stages of the approach were tested. The input included micro-CT scans of porous ceramic structure, which is quite similar to commercial porous scaffolds. The results show that the proposed method is feasible for design and manufacture of micro-scale scaffolds.

Shape verification using dual-wavelength holographic interferometry

In automotive industry there is an interest of controlling the shape of a large number of identical components on-line in the manufacturing process. We propose a method to do this by capturing a digital hologram of the object and then using information from its computer aided design (CAD) model to calculate the shape and determine the agreement between the manufactured object and the CAD-model. The holographic recording of the object is done using dual wavelengths with a synthetic wavelength of approximately 400 μm. The optical measurement results in a wrapped phase map with the phase values in the interval [ − π, π]. Each phase interval represents a depth distance on the object of about 0.2 mm. The phase unwrapping is done iteratively using information from the CAD-model. This implies that it is possible to measure large discontinuities on the surface of the measured object. The method also gives a point-to-point correspondence between the measurement and the CAD-model which is vital for tolerance control.

An image‐guided technique for planning and verification of supine craniospinal irradiation

We present a technique for planning and verification of craniospinal treatment with the patient in the supine position. Treatment delivery and verification is streamlined through the use of modern imaging techniques. Treatments use two lateral brain fields abutted to a single or pair of posterior spine fields. Treatment delivery is simplified by aligning all isocenters in the anterior‐posterior and lateral directions. Patient positioning is accomplished via on‐board kV imaging. Verification of field shape and junctions is accomplished with BB placement and MV portal imaging. Daily treatment is simplified by using only longitundinal couch shifts, which are recorded in the patient chart and RV database. The technique is simple to implement in a clinic that is already using a similar beam arrangement with the patient prone. It requires no additional devices to be fabricated (for immobilization or QA), and it takes advantage of all the existing elements of a modern linac.PACS number: 87.55.‐x

Shape verification aimed for manufacturing process control

We describe a method to verify the shape of manufactured objects by using their design model. A non-contact measuring method that consists of a stereo-camera system and a single projected fringe pattern is used. The method acquires one image from each camera. Additional shape information from the design model is also used. This surface-measurement method gives an accuracy of about 45 μ m . Deviations from the design model within ±1.6 mm can be correctly detected. The measured surface representation is matched to the design model using the ICP-method. Fast performance has been considered adapting the method for on-line use.

Simple verification of the parabolic shape of a rotating liquid and a boat on itssurface

This article describes a simple and inexpensive way to create and to verify the parabolicsurface of a rotating liquid. The liquid is water. The second part of the article deals withthe problem of a boat on the surface of a rotating liquid.

Automated verification of shape, size and bag properties via user-defined predicates in separation logic

Despite their popularity and importance, pointer-based programs remain a major challenge for program verification. In recent years, separation logic has emerged as a contender for formal reasoning of pointer-based programs. Recent works have focused on specialized provers that are mostly based on fixed sets of predicates. In this paper, we propose an automated verification system for ensuring the safety of pointer-based programs, where specifications handled are concise, precise and expressive. Our approach uses user-definable predicates to allow programmers to describe a wide range of data structures with their associated shape, size and bag (multi-set) properties. To support automatic verification, we design a new entailment checking procedure that can handle well-founded predicates (that may be recursively defined) using unfold/fold reasoning. We have proven the soundness and termination of our verification system and built a prototype system to demonstrate the viability of our approach.

基于手部尺寸特征的手形认证方法

基于手部尺寸特征的手形认证方法