Contour Measurement Research Articles

Hand shape classification in various pronation angles using a wearable wrist contour sensor

Hand gestures are potentially useful for communications between humans and between a human and a machine. However, existing methods entail several problems for practical use. We have proposed an approach to hand shape recognition based on wrist contour measurement. Especially in this paper, two assignments are addressed. First is the development of a new sensing device in which all elements are installed in a wrist-watch-type device. Second is the development of a new hand shape classifier that can accommodate pronation angle changes. The developed sensing device enables wrist contour data collection under conditions in which the pronation angle varies. The classifier recognizes the hand shape based on statistics produced through data forming and statistics conversion processes. The most important result is that no large difference exists between classification rates that include or those that exclude the independent (preliminary) pronation estimation process using inertia measurement units. This result shows two possible insights: (1) the wrist contour has some features that depend on the hand shape but which do not depend on the pronation angle, or (2) the wrist contour potentially includes pronation angle variation information. These insights indicate the possibility that hand shape can be recognized solely from the wrist contour, even while changing the pronation angle.

Anthropometric measurements of the orbital contour and canthal distance in young Turkish

IntroductionThis study is aimed to define the mean values of the different anthropometric measurements of right and left orbits and giving the average of the basic measurements of the soft orbital tissues in young Turkish and compare the obtained measurements between women and men. Materials and methods115 students (59 female and 56 male) from Yasar Dogu School of Physical Education and Sport of Ondokuz Mayis University participated in the study. The age of participants were ranging between 18 and 30 years. 12 measurements were done, 3 for general body measurement and 9 for orbit contour region. The parameters of measurements are the intercanthal width (en-en), the biocular width (ex-ex), interpupillary distance (p-p), palpebral fissure width right-left (ex-en/r-l), height of the orbit right-left (os-oi/r-l), palpebral fissure height right-left (ps-pi/r-l). ResultsThe mean values of en-en, ex-ex, p-p, ex-en/r-l, os-oi/r-l, and ps-pi/r-l in males the mean values were, 28.68±3.61mm, 96.43±11.90mm, 61.73±3.77mm, 36.02±2.71mm/35.63±2.79mm, 35.19±4.37mm/35.13±4.49mm, 10.06±1.74mm/10.30±1.90mm, respectively. However, in females were 27.84±2.90mm, 95.08±9.85mm, 58.99±3.22mm, 35.01±2.27mm/34.66±2.28mm,35.15±3.64mm/35.79±3.70mm, 10.31±1.43mm/10.37±1.73mm, respectively. DiscussionThe results indicate that the measurements were higher in males than in females (p<0.001). The normative anthropometric data presented in this study would be useful for clinical interpretation of periocular pathology and serve as reference values when planning aesthetic and posttraumatic surgical interventions.

Development and Practicality of a Scanning Point Autofocus Instrument for High Speed Areal Surface Texture Measurement

A point autofocus instrument (PAI) is widely used for the roughness and contour measurement of various precision processing surfaces, because it is capable of measuring a large area in high precision. The only disadvantage of PAI is to require a long measurement time. Its conventional index measurement stops the scanning stage in order to obtain each coordinate value of the fixed sampling pitch. Hence, it was necessary to develop a scanning point autofocus instrument (SPAI) which can obtain coordinate values while the scanning stage is moving. As an achievement of the development, the SPAI offers 26 times faster measurement speed than that of the index measurement with equivalent accuracy. The SPAI easily measures 3D surface texture and provides quantitative evaluations of the precision processing surfaces.

Cell Contour Irregularity Feature Extraction Methods based on Linear Geometric Heat Flow Curve Evolution

When the cytological smear method is used to check cervical lesions, the irregularity of the cells contour is essential for smear image interpretation and has the vital significance for research on computer aided diagnosis of cervical lesions. Aimed at measuring the regularity of cells outlines, based on the characteristic that the normal cell smears is generally circular, oval, convex polygon, we put forward a cell contour irregularity feature extraction and measurement method based on linear geometric heat flow curve evolution, in which the curve of cells outline is dealt with linear geometric heat flow curve evolution to totally convex (i.e. no curvature zero crossing) and compared with the original contour to extract indexes which can describe irregularity features of cell contour. Experimental results show that the method proposed in this paper can better describe the irregularity of cell contour and distinguish cells of different lesions.

Adaptive Surface Visualization of Vessels with Animated Blood Flow

AbstractThe investigation of hemodynamic information for the assessment of cardiovascular diseases (CVDs) gained importance in recent years. Improved flow measuring modalities and computational fluid dynamics (CFD) simulations yield in reliable blood flow information. For a visual exploration of the flow information, domain experts are used to investigate the flow information combined with its enclosed vessel anatomy. Since the flow is spatially embedded in the surrounding vessel surface, occlusion problems have to be resolved. A visual reduction of the vessel surface that still provides important anatomical features is required. We accomplish this by applying an adaptive surface visualization inspired by the suggestive contour measure. Furthermore, an illustration is employed to highlight the animated pathlines and to emphasize nearby surface regions. Our approach combines several visualization techniques to improve the perception of surface shape and depth. Thereby, we ensure appropriate visibility of the embedded flow information, which can be depicted with established or advanced flow visualization techniques. We apply our approach to cerebral aneurysms and aortas with simulated and measured blood flow. An informal user feedback with nine domain experts, we confirm the advantages of our approach compared with existing methods, e.g. semi‐transparent surface rendering. Additionally, we assessed the applicability and usefulness of the pathline animation with highlighting nearby surface regions.

Repeatability of the Contour Method for Residual Stress Measurement

This paper describes the results of a residual stress measurement repeatability study using the contour method. The test specimen is an aluminum bar (cut from plate), with cross sectional dimensions of 50.8 mm × 76.2 mm (2 in × 3 in) with a length of 609.6 mm (24 in). There are two bars, one bar with high residual stresses and one bar with low residual stresses. The high residual stress configuration (±150 MPa) is in a quenched and over-aged condition (Al 7050-T74) and the low residual stress configuration (±20 MPa) is stress relieved by stretching (Al 7050-T7451). Five contour measurements were performed on each aluminum bar at the mid-length of successively smaller pieces. Typical contour method procedures are employed with careful clamping of the specimen, wire electric discharge machining (EDM) for the cut, laser surface profiling of the cut faces, surface profile fitting, and linear elastic stress analysis. The measurement results provide repeatability data for the contour method, and the difference in repeatability when measuring high or low magnitude stresses. The results show similar repeatability standard deviation for both samples, being less than 10 MPa over most of the cross section and somewhat larger, around 20 MPa, near the cross section edges. A comparison with published repeatability data for other residual stress measurement techniques (x-ray diffraction, incremental hole drilling, and slitting) shows that the contour method has a level of repeatability that is similar to, or better than, other techniques.

Nanometer-precision contour-measurement technique for the diagnostics of multilayer nanostructures

A new technique of contour measurements with nanometer precision for the diagnostics of multilayer structures and other samples applied in optical and silicon technologies, and metal processing is proposed. This paper describes the development of two main technical solutions to achieve and verify nanometer resolution of the contour measuring instrument—single-crystal-silicon guide and test plates. The use of a crystal as a linear guide gives the possibility to achieve long-term stability of its bearing surface within a few nanometers. A test sample of a multilayer structure is developed and its parameters are controlled by means of transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge spectroscopy (XANES). The results of measuring test samples with a step height of 100 and 200 nm by means of the contour measurement technique are presented.

Full Scale Calibration of a Combined Tactile Contour and Roughness Measurement Device

In current production metrology contour and roughness of work pieces has to be controlled in demanding small tolerances. It is important that the results not only have to be accurate, but also the measurement has to be performed effective and fast. It would be convenient to have the possibility measuring first a continuous surface profile and than performing different evaluations on adjacent segments. We describe a measurement system which is based on a tactile probe with a diamond tip. The position of each axis is measured by high resolution and high accuracy digital scales. The instrument is calibrated and traced back by only using one precision sphere covering approximately the whole measuring range of 24 mm. It is shown that with only that macroscopic calibration and adjustment the accuracy for roughness measurement in all arbitrary vertical positions is reached in the nm-range. The calibration and adjustment process is described and we show the verification of the accuracy by measuring several surface specimens. The results are compared to a Physikalisch-Technische Bundesanstalt (PTB) calibration certificates for those surface roughness standards.

Hybrid measurement to achieve satisfactory precision in perioperative cardiac output monitoring.

Advanced haemodynamic monitoring employing minimally invasive cardiac output measurement may lead to significant improvements in patient outcomes in major surgery. However, the precision (scatter) of measurement of available generic technologies has been shown to be unsatisfactory with percentage error of agreement with bolus thermodilution (% error) of 40% to 50%. Simultaneous measurement and averaging by two or more technologies may reduce random measurement scatter and improve precision. This concept, called the hybrid method, was tested by comparing accuracy and precision of measurement relative to bolus thermodilution using combinations of three component methods. Thirty patients scheduled for either elective cardiac surgery or liver transplantation were studied. Agreement with simultaneous bolus thermodilution of hybrid combinations of continuous thermodilution (QtCCO) or Vigeleo™/FloTrac™ pulse contour measurement (QtFT) with pulmonary Capnotracking (QtCO2) was assessed pre- and post-cardiopulmonary bypass or pre- and post-reperfusion of the donor liver and compared with that of the component methods alone. Hybridisation of QtCO2 (% error 42.2) and QtCCO (% error 51.3) achieved significantly better precision (% error 31.3) than the component methods (P=0.0004) and (P=0.0195). Due to poor inherent precision of QtFT (% error 82.8), hybrid combination of QtFT with QtCO2 did not result in better precision than QtCO2 alone. Hybrid measurement can approach a 30% error, which is recommended as the upper limit for acceptability. This is a practical option where at least one component method, such as Capnotracking, is automated and does not increase the cost or complexity of the measurement process.

A Validated Numerical Model for Residual Stress Predictions in an Eight-Pass-Welded Stainless Steel Plate

Welding processes create a complex transient state of temperature that results in post-weld residual stresses. The current work presents a finite element (FE) analysis of the residual stress distribution in an eight-pass slot weld, conducted using a 316L austenitic stainless steel plate with 308L stainless steel filler metal. A thermal FE model is used to calibrate the transient thermal profile applied during the welding process. Time-resolved body heat flux data from this model is then used in a mechanical FE analysis to predict the resultant post-weld residual stress field. The mechanical analysis made use of the Lemaitre-Chaboche mixed isotropic-kinematic work-hardening model to accurately capture the constitutive response of the 316L weldment during the simulated multi-pass weld process, which results in an applied cyclic thermo-mechanical loading. The analysis is validated by contour method measurements performed on a representative weld specimen. Reasonable agreement between the predicted longitudinal residual stress field and contour measurement is observed, giving confidence in the results of measurements and FE weld model presented.

Detection and Measurement of Fetal Abdominal Contour in Ultrasound Images via Local Phase Information and Iterative Randomized Hough Transform

Due to the characteristic artifacts of ultrasound images, e.g., speckle noise, shadows and intensity inhomogeneity, traditional intensity-based methods usually have limited success on the segmentation of fetal abdominal contour. This paper presents a novel approach to detect and measure the abdominal contour from fetal ultrasound images in two steps. First, a local phase-based measure called multiscale feature asymmetry (MSFA) is de ned from the monogenic signal to detect the boundaries of fetal abdomen. The MSFA measure is intensity invariant and provides an absolute measurement for the signi cance of features in the image. Second, in order to detect the ellipse that ts to the abdominal contour, the iterative randomized Hough transform is employed to exclude the interferences of the inner boundaries, after which the detected ellipse gradually converges to the outer boundaries of the abdomen. Experimental results in clinical ultrasound images demonstrate the high agreement between our approach and manual approach on the measurement of abdominal circumference (mean sign difference is 0.42% and correlation coef cient is 0.9973), which indicates that the proposed approach can be used as a reliable and accurate tool for obstetrical care and diagnosis.

180 光学システムを用いたダイヤモンド切削工具切れ刃輪郭形状の3次元測定に関する研究

180 光学システムを用いたダイヤモンド切削工具切れ刃輪郭形状の3次元測定に関する研究

Integral momentum balance on a growing bubble

The integral momentum balance on a growing boiling bubble is investigated. All forces acting on the bubble are detailed, and the methods and assumptions used to calculate their integral resultants are discussed. The momentum balance computation is then performed using experimental data of bubbles growing on an artificial nucleation site in a controlled environment. The relative magnitude of each force component is compared, showing negligible dynamic forces, upwards forces composed mainly of the buoyancy and contact pressure components, and downwards forces being exclusively due to surface tension and adhesion. The difficulty encountered in measuring the apparent contact angle due to mirage effects has been highlighted; a new method, fitting numerically simulated bubble profile to the contour measurements has been proposed and used to correct the effects of refraction on the bubble profile determination. As all forces acting on the bubble were measured, it was possible to estimate the residuals of the momentum balance. Their small value validated both the expressions used for the forces and the methodology to evaluate their value.

Contact-Type Profile Measuring Device Using Laser Interferometry System Incorporating Hybrid Actuating System

This paper proposes a contact-type profile measuring device using a laser interferometry system for precision components. This measuring device consists of an XY-table actuated by linear motors to obtain large operational ranges, an active contact probe driven by piezoelectric actuators to provide a small measuring force, and a specially configured optical path to reduce Abbe’s error. Fundamental experiments were performed to examine the control performance of the active probe, forward and backward motion behaviors of the hybrid actuating system, and contour measurement for an asphericmold. As one example of themeasured results, a maximum form error of 1.45 µm was obtained for an aspheric surface with a measured span of 4 mm and a sag of 37 µm. As a prototype highprecision measuring system, the effectiveness of the optical path and actuating system have been demonstrated. Further studies are suggested to improve the system performance by reducing the measuring force, increasing the measuring speed, and providing a scanning function.

Mapping Multiple Components of the Stress Tensor Using the Contour Method

The purpose of this paper is to demonstrate a) application of the contour method in measuring residual stresses in large complex geometries such as a welded pipe, b) the power of combining the contour measurement approach with other measurement methods in order to map multiple components of stress tensor in structures, c) the capability of the contour method for characterising residual stresses where there are steep gradients of stress, for example in an electron beam welded plate, and d) mapping multiple components of residual stress in thick structures using multiple cuts.

Hydrophilic Guidewires: Evaluation and Comparison of Their Properties and Safety

To compare physical and mechanical properties of 10 commercially available hydrophilic guidewires. In vitro testing was performed to evaluate 10 different straight hydrophilic guidewires (5 regular and 5 stiff wires): Glidewire, NiCore, EZ Glider, Hiwire, and Zipwire. The forces required for tip perforation, tip bending, shaft bending, and friction during movement were measured for all 10 wires. The tip contour was measured using high power light microscopy. The Glidewire required the greatest force to perforate our model (P = .01). The EZ Glider, Zipwire, and Glidewire had the lowest tip bending forces (P <.001). The Glidewire had the stiffest shaft (P <.001). The EZ Glider and Glidewire required the greatest forces in the friction test (P <.001). Regarding the stiff guidewires, the GlidewireS required the greatest force in the perforation test (P ≤.05). The GlidewireS and EZ GliderS required the lowest tip bending force (P ≤.004). The ZipwireS and NiCoreS had the stiffest shafts (P ≤.01). The GlidewireS required the greatest force in the friction test (P <.001). Measurement of the tip contour showed the Zipwire, HiwireS, and EZ GliderS had the roundest tips. Each wire has unique properties with advantages and disadvantages. The Glidewires (both stiff and regular) have the lowest potential for perforation, although they are less slippery. The Glidewire and EZ Glider required the least tip force to bend around a point of obstruction.

Clinical failure analysis of contemporary ceramic-on-ceramic total hip replacements

The present study investigates the performance of ceramic-on-ceramic total hip replacements by combining a retrieval analysis with a survivorship analysis to elucidate mechanisms that led to clinical failure. Semiquantitative surface damage assessment, contact profilometry, contour measurements, and scanning electron microscopy were performed to characterize the types and quantify the extent of surface damage on the retrieved ceramic components. The implantation period was positively correlated with both damage scores of the femoral heads (R = 0.573, p < 0.001) and the acetabular cups (R = 0.592, p < 0.001). Increased maximal out-of-roundness values of the femoral heads correlated with both increased metal transfer damage score (R = 0.384, p = 0.023) and increased stripe damage score (R = 0.729, p ≤ 0.001) of the acetabular liners. The damage rate (damage score/year) for both the retrieved heads and acetabular liners was at least 2.2-fold greater at inclination angles of >45° than the damage rate at inclination angles of ≤45°. For the retrieved femoral heads only, the linear wear rate of 25.5 ± 21.3 µm/year at inclination angles of >45° was 6-fold greater than the linear wear rate of 4.2 ± 2.3 µm/year at inclination angles of ≤45°. Metal transfer on the ceramic bearing surface could possibly contribute to fluid-film starvation and, in combination with an increased inclination angle, may facilitate an adhesive wear mechanism associated with stripe surface damage. At our institution, the clinical survivorship of ceramic-on-ceramic total hip replacements was 98.9% (a total of 9 out of 815 patients were revised within 10 years after total hip arthroplasty) with revision as the end point, suggesting their safe use in younger patients.

Study of Polishing Technology for Aspheric Surface with High Efficiency

In recent years, for the compact system structure of aspheric lens, it has improved the image quality and excellent performance. More and more applications, in a variety of precision instruments, require the aspheric surface machining precision, fast, batch production. In order to further seek the effective method of aspheric surface processing, the aspheric NC machining technology is put forward. Therefore, this paper studies the aspheric surface in NC machining process of milling molding, polishing and polishing equipment related process parameters. Focusing on the milling process of various parameter settings, the resilient mold and small grinding head fixed combination method of polishing is introduced into the milling feedback compensation, solution of the elastic die polishing on the profile accuracy of destruction and processing to meet the requirements of the drawings of components: the contour measurement method on the profile accuracy of testing and surface shape accuracy of 0.5924um.

基于无衍射栅型结构光投影的角膜轮廓测量

基于无衍射栅型结构光投影的角膜轮廓测量

Residual stresses in P91 steel electron beam welds

This paper describes the characterisation of residual stress in electron beam welded P91 ferritic–martensitic steel plates (9 mm thick) by neutron diffraction and contour measurement methods. The novelty of the work lies in revealing the residual stress profile at a fine length scale associated with a ∼1 mm wide fusion zone. A characteristic ‘M’ shaped distribution of stresses across the weld line is observed with high tensile peaks situated just beyond the heat affected zone/parent material boundary. Measured stresses close to the weld centreline are significantly less tensile than the adjacent peaks owing to martensitic phase transformation during cool down of the weld region. The effect of applying a second smoothing weld pass is shown to be undesirable from a residual stress standpoint because it increases the tensile magnitude and spread of residual stress. The results are suitable for validating finite element predictions of residual stress in electron beam welds made from ferritic–martensitic steels.