Dimensional Measurement System Research Articles

A biomimetic chiral auxetic vertebral meta-shell

Abstract The work presents a novel thin-walled biomimetic auxetic meta-shell for patient-specific vertebral orthopedic implants. The proposed design stemmed from the concept of an intrinsically multiple curved auxetic meta-structure, which is created by folding a 2D bio-inspired chiral geometry according to the morphology of human vertebral cortical bones. Through a multi-view stereo Digital Image Correlation (DIC) system, we investigated the mechanical response of a bio-grade titanium (Ti6Al4V ELI) additively manufactured prototype of the meta-structure under compressive loadings. In addition, we analyzed the morphology of the prototype using a scanning electron microscopy (SEM) and an optical image dimension measurement system both before and after compressive tests. An accurate Finite Element model, which exactly reproduced the geometry of the 3D printed meta-shell, was implemented and calibrated against experimental results, obtaining a precise prediction tool of its mechanical response. The findings of this work demonstrate that the designed meta-shell shows a peculiar auxetic behavior, a targeted stiffness matching to that of human vertebral bone tissues and a higher global elastic strain capability compared to those of monolithic traditional vertebral body replacements.


Case study using APDMS and RPEMS for SAWL pipes and benefits for offshore pipelay

This paper reviews an Automatic Pipe Dimension Measurement System (APDMS) and a Robotic Pipe End Measurement System (RPEMS) which can measure 19 and 9 parameters with the help of 72 and 6 measurement sensors respectively. APDMS and RPEMS are integrated into one optical measurement system, using laser triangulation, coupled with Systems, Applications and Products in Data Processing (SAP) integration and its own calibration modulus which provides an accurate solution to all pipe measurements. Two longitudinal submerged arc welded offshore projects were executed for an offshore pipe lay with close dimensional tolerances measured using the APDMS for one project and RPEMS for the other project. The radii data, assessed from the newly calculated common centre of all cross-sectional data, was used to line up the two adjacent pipes in a faster and more accurate way. By knowing the shape of the pipe ends based on this radii data, the best relative rotation of these two pipes can be determined and any misalignment will be verified and will stay within the requirements. The extensive database available for each pipe helped to match the line pipes with similar or close out-of-roundness at pipe ends resulting in good fitment of the pipes and ultimately quality welds, together with more pipe joints per day, resulting in a faster completion of the project. This paper shows the significance of using both systems.

Clinical efficacy and kinematic analysis of Chinese knotting technique-assisted posterior cruciate ligament reconstruction: A retrospective analysis.

To investigate the clinical efficacy and knee joint kinematic changes of posterior cruciate ligament (PCL) reconstruction assisted by Chinese knotting technique (CKT). A retrospective analysis was conducted on 88 cases of PCL reconstructive surgery admitted between September 2016 and September 2020. All patients were operated on by the same senior doctor and his team. The patients were divided into 2 groups according to whether the CKT was applied, with 44 cases in each group. Both groups received active rehabilitation treatment after surgery. All patients were followed up for more than 2 years. International knee documentation committee, hospital for special surgery (HSS), and Lysholm scores were used to evaluate the clinical efficacy of the 2 methods at 3, 12, and 24 months after surgery. The motion cycle and kinematic indices of the knee joint were measured by the Opti_Knee three-dimensional motion measurement system before surgery and at 3, 12, and 24 months after surgery. A secondary arthroscopic examination was performed at 12 months after surgery, MAS score was used to evaluate the secondary endoscopic examination of PCL. All the patients had wound healing in stage I without infection. International Knee in both sets Documentation Committee scores, HSS scores and Lysholm scores were gradually improved at all time points (P < .05); compared with the traditional group, the HSS score was higher in the reduction group 12 months after surgery (P < .05), but there was no significant difference at 24 months after surgery. 12 months and 24 months after 3 dimensional motion measurement system using Opti_Knee showed a reduction group before and after displacement and displacement of upper and lower range than the traditional group (P < 0. 05). One year after surgery, the good and good rate of MAS score reduction group was higher than traditional group. CKT assisted PCL reconstruction can improve the subjective function score of the affected knee joint and the results of secondary microscopy. Satisfactory knee kinematic function can be obtained in the early stage, and the anteroposteric relaxation of the knee joint can be reduced.

Simple and High‐Precision Hand–Eye Calibration for 3D Robot Measurement Systems

Three dimensional (3D) robot measurement systems, with binocular planar structured light cameras (3D cameras) installed at the terminal flange of robots, are widely used to measure complete workpieces by stitching point clouds obtained from various sampled poses. To ensure accurate stitching, hand–eye calibration is necessary. However, 3D cameras often demonstrate low precision in measuring jumping edges and vertices, resulting in challenges when selecting appropriate calibrators and calibration methods for hand–eye calibration. We propose a simple and high‐precision hand–eye calibration method for 3D robot measurement systems. Initially, a single sphere is utilized as the calibrator, and its poses are observed using specific robotic motions. Subsequently, the hand–eye calibration problem is formulated as a well‐known equation, , relying solely on the high‐precision relative pose of the robot. Finally, a novel simultaneous solution for and the corresponding closed‐form initial solution are introduced. Simulations and experiments confirm that the proposed method exhibits high noise resistance and achieves high‐precision calibration, even with a limited calibration data quantity. Compared with traditional methods, the fitting error of the proposed method can be reduced from over 0.9 mm to less than 0.6 mm.

A novel method to calibrate the rotation axis of a line-structured light 3-dimensional measurement system

Rotation axis calibration is the key to line-structured light 3-dimensional (3D) measurement. The traditional calibration method based on circle fitting only uses the position information of the calibration target and ignores the orientation information, which is easily affected by noise. This paper proposes a new calibration method combining the orientation and position information to improve the calibration accuracy. Compared with the circle fitting method, the added orientation information makes the description of rotation more complete. On this basis, an improved extrinsic parameters estimation method is proposed to obtain more accurate position and orientation information of the target, which further improves the calibration accuracy. The experiment results show that, the radius error is reduced by about 90% and the standard deviation of radius error is reduced by about 40% compared with the traditional circle fitting method.

Large-scale and high-depth three dimensional scanning measurement system and algorithm optimization

Tapping scanning mode is an important method for measuring surface topography at the nanometer scale. It is widely used because it can eliminate lateral force and reduce damage to the tested sample. Research on three dimensional (3D) scanning technology with a large range and high depth-to-width ratio has important practical significance and engineering application value because the current scanning probe microscope has the limitations of small measurement ranges and weak Z-direction measurement ability. The high-frequency resonance of the quartz tuning fork, combined with the tungsten stylus, is used in this paper. It has the ability to measure the surface profile of the microdevice with a large aspect ratio. The proposed 3D scanning measurement system has realized a microstructure measurement with a depth of ∼58 µm. The entire measuring range is 400 × 400 × 400 µm3, and the vertical resolution reaches 0.28nm. The system can accurately obtain the 3D surface topography of the microfluidic biochip. In addition, a sliding window algorithm (SWA) based on errors in the scanning process and low scanning efficiency is proposed. Compared with the point-by-line scanning algorithm, the proposed SWA reduces the mean value of the squared residuals of the 3D profile by 7.70%, thereby verifying the feasibility of the algorithm. The 3D scanning measurement system and the algorithm in the tap mode provide an important reference for the 3D topography measurement of microstructures with large aspect ratios.

Using 3D Scanning for Accurate Estimation of Termination Points for Dimensional Quality Assurance in Pipe Spool Fabrication

Increased prefabrication and modularization have resulted in fabrication shops producing more complex assemblies with tighter tolerances. Most measurements in fabrication shops are still done using manual tools that are not accurate enough for engineering tolerance specifications, which can lead to rework. Three dimensional (3D) scanning and measurement systems can provide increased accuracy and digital integration capabilities, however they do not sufficiently support fast and accurate dimensional quality assurance (DQA) of pipe spool fabrication. This is because no dimensional quality assurance methods to date have focused solely on termination points for pipe spool assemblies. In the present article, a new scan-vs-BIM method is developed to accurately estimate termination points for 3D scanned cylindrical assemblies. This method relies on statistically fitting circular features at termination points and thus eliminating conventional issues with target placement for laser trackers and measurement readings for tape measures. The method is tested in an industrial-scale experiment, where 30 pipe spool assemblies were fabricated, and more than 400 quality control steps completed. The accuracy of termination point detection was benchmarked against results from a laser tracker and compared against commercial scan-to-BIM software. Results show that the developed method has an average accuracy of 1.01 mm and is significantly better than the scan-to-BIM software with an average accuracy of 4.75 mm.

Computer vision-based dimension measurement system for olive identification

Olive tree is an important portion of the human history of Mediterranean nations. On the other hand, local varieties are important for each producer regions and even countries. So, olive cultivars are important for agricultural production for these people. The traditional pomological identifiers of the olive trees based on fruits and leaves, also morphometric analysis of size, additionally shape elliptic analysis of endocarp. Because of this reason, in this study, for the ‘Picual’ olive cultivar identification, a fast and easy method was presented. For this aim, ‘Picual’ olive leaf, fruit, and stone dimension measurement values obtained from real-time video images. ‘Picual’ olive fruit, stone, leaf samples evaluated by using real-time computer vision measurements. Regression analysis was applied to the data which was obtained from real-time video and caliper measurements. According to the regression coefficient results, the regression between caliper length measurement (OLLM) and computer vision video length measurement (OLLCV) found as 98.9%, also the regression between caliper width measurement (OLWM) and computer vision video width measurement (OLWCV) found as 97.9% at ‘Picual’ leaves, additionally, the regression between caliper length measurement (OFLM) and computer vision video length measurement (OFLCV) found as 98.5% the regression between caliper width measurement (OFWM) and computer vision video width measurement (OFWCV) found as 98.1 % at ‘Picual’ fruits, at last, the regression between caliper length measurement (OSLM) and computer vision video length measurement (OSLCV) found as 86.2%, the regression between caliper width measurement (OSWM) and computer vision video width measurement (OSWCV) found as 75.3% at ‘Picual’ stones.

Three Dimensional Measurement System for the Dynamic Deformation of Aero-engine Blade Profile

In order to solve the technical problem of three-dimensional profile measurement of aero-engine blades with high speed rotation, an optical dynamic measurement system for aero-engine blades was developed. Firstly, the system is calibrated by the algorithm of spatial truncation phase calibration to establish the index between truncation phase and spatial coordinates. During the measurement, the deformation map of the rotating measured blade is obtained by synchronous projection and snapshot. By using the fast Fourier algorithm, the truncation phase is obtained, and then the profile information of blade can be obtained through the truncation phase and spatial coordinate index. Through the design and construction of the blade simulation platform and dynamic measurement experiment system, the three-dimensional profile data of the blade at different rotating speeds are obtained, compared and analyzed, and then the overall profile deformation law is discovered, which verifies the effectiveness and feasibility of the algorithm. The system can obtain the dynamic profile information of the whole blade completely, and provide innovative technical means for blade design verification and performance analysis.

Multi-sensor registration method based on a composite standard artefact

Registration is a critical and essential procedure in any multi-sensor dimensional measuring systems. Most of the traditional registration methods are achieved by measuring a common standard by multiple sensors; however, it is difficult to ensure that heterogeneous sensors measure the same feature points. In this study, a new multi-sensor registration method based on a composite standard artefact is proposed. The base of the standard artefact is equipped with a standard sphere and a standard chrome-circle for registering the visual sensor (VS) and the tactile probe sensor (TPS) on a multi-sensor dimensional measuring machine. The VS and TPS measure the standard chrome-circle and the standard sphere, respectively. The coordinate system conversion parameters between the two sensors were solved based on the constant distance between the standard chrome-circle centre and the standard sphere centre. Both the simulations and experiments demonstrate higher precision and stability of the proposed method for the registration of multiple heterogeneous sensors in high-precision dimensional measurement systems. The root mean square errors of the registration experiments in X and Y -directions are 6μm and 4μm, respectively. The combined standard uncertainties are uc(tx)=1.6μm and uc(ty)=1.2μm.

Research on the on-line dimensional accuracy measurement method of conical spun workpieces based on machine vision technology

An on-line dimensional accuracy measurement method was proposed based on machine vision technology to realize the real-time measurement of straightness and roundness of spun workpieces during spinning. An image acquisition system was developed to obtain the real-time images of conical spun workpiece and the camera calibration was conducted. The edges of the conical spun workpiece were extracted by region of interest (ROI) extraction, image deblurring, denoising and edge detection. The straightness and roundness of the spun workpieces were automatically calculated by writing the calculation program. The reliability of on-line dimensional accuracy measurement system was verified by comparing with measurement results of 3D measuring machine. The results show that the straightness and roundness calculated by measurement system confirm well with that measured by 3D measuring machine, the relative errors between which are less than 10%, and the average detection time of straightness and roundness is 98.5 ms and 69.3 ms, respectively.

Application and comparative analysis on three dimensional camera measurement system in full size inspection of batch production parts

Box-type parts are the basic parts of general machines, they assemble the shaft, sleeve, gear and other related parts of the machine into a whole, so as to maintain the correct mutual position accuracy between the parts. Their complex forming structure, large matching dimensions and high precision requirements directly affect the accuracy, performance and life of the machine. Aiming at the problems of large size and low efficiency of single piece inspection for box parts, this paper takes the spindle box of horizontal lathe as the research object, simulates through virtual testing platform, puts several parts of the same box parts in a certain order, determines the appropriate angle and shoots batch parts placement model in many directions, and adopts three-dimensional method. The camera measurement system detects the full size of the same batch of products and obtains the test results. On this basis, the traditional laser tracking measurement method is used to detect and compare the randomly selected single spindle box. The comparison results show that the three-dimensional camera measurement method can detect the forming accuracy of batch box parts well under the appropriate position and photographic angle, and the full-scale measurement error can be effectively controlled within the technical allowable range. This study provides a preliminary basis for the three-dimensional camera measurement technology in improving the efficiency and accuracy of full-scale measurement of batch box parts.

Digitalization of Human Head Anthropometry Measurement Using Pixels Measurement Method

Head Anthropometry is a part of anthropometry that needed to be measured carefully. It is because human head becomes an important part that necessary to be protected. The protection aims to look after the safety of the human head. Safety factors can be achieved by designing head products. Therefore, head anthropometry data is required to make a product design Currently, data retrieval of head anthropometry is still using several measuring devices such as anthropometers, sliding callipers, spreading callipers, and tape gauges. This measurement method makes the standard deviation become higher and also take a lot of time to capture huge amounts of anthropometry data. However, the problem has been resolved by other study research with building a head dimension measurement system using digital camera. But the system still need the integration with digital camera. This study uses the IP Camera that has been integrated with the system to capture human head from the front and side. The captured image is segmented into several areas based on head dimension. Then, the image is processed using pixel measurement method by performing feature extraction on each head dimension to get the result of head dimension measurement. The result shows that calliper measurement and system measurement against ten of fourteen human head anthropometry dimensions is identical with the best distance between IP Camera and the head as far as 200 cm. This head anthropometry data is expected to make a contribution to Indonesian Ergonomics Society.

Calibration and uncertainty estimation of non-contact coordinate measurement systems based on Kriging models

Non-contact three dimensional (3D) coordinate measurement systems (CMSs) using optical scanning techniques have the advantage of fast acquiring large numbers of points. However, these systems are known to be less accurate in comparison to the contact-based counterparts. To improve the measurement accuracy of non-contact 3D CMSs, a novel Kriging models-based calibration and uncertainly estimation method is proposed. The spatial correlation of measurement uncertainty is investigated and the calibration values for unmeasured points based on Kriging models are estimated. A procedure of best model selection is presented, and the influence of the calibration model parameters is analyzed. The proposed calibration method is validated through an ATOS II triple scan system. The results show that a significant accurate improvement for the non-contact 3D measurement system is achieved.

Variations in Electroosmotic Flow Outside Glass Nanopores with Species of Monovalent Cation

Nanopores are an important technology in molecular sensing systems. Their behaviour is strongly affected by flow characteristics that are not well understood. Utilising a novel 3 dimensional combination optical tweezers and capillary nanopore measurement system, we have measured flow behaviour outside conical glass nanopores as a function of species of group 1 cation. We present a full 3 dimensional flow field about the nanopore. We use this 3 dimensional measurement system to find the flow force as a function of distance from the pore, allowing us to determine the momentum flux for each salt condition. We find strong salt dependence on the strength of momentum flux from the nanopore. Additionally we find previously reported voltage dependent flow reversal to be dictated by salt species. For a subset of species we observe EOF in the expected direction as predicted by classical electrokinetic theory, while for others the direction of the flow is reversed. We present a model explaining the observed behaviour. These data and corresponding model are key to understanding ion transport, fluid flow and translocation dynamics in voltage driven nanopore systems.

Research on geometric dimension measurement system of shaft parts based on machine vision

Computer vision measurement systems have become more and more widely used in industrial production processes. Traditional manual measurement methods cannot guarantee product quality. Therefore, it is of great significance to improve the technology level of the manufacturing industry to study the automatic measurement system for the dimension of shaft parts with low cost, high precision, and high efficiency. A geometric part measurement system for shaft parts based on machine vision is presented in this paper. It uses the CCD camera to get the image. First, it preprocesses the collected images. In view of the influence of the noise and other factors, the wavelet denoising is used to denoise the image. Then, an improved single pixel edge detection method is proposed based on the Canny detection operator to extract the edge contour of the part image. Finally, the geometrical quantity algorithm is applied to the measurement research, and the measured data are obtained and analyzed. The experimental results show that the repeatability error of the system is less than 0.01 mm.

A method for measuring the thermal geometric parameters of large hot rectangular forgings based on projection feature lines

The online dimensional measurement of large hot forging is an important procedure in the forging process. Because of different production demands, the final geometrical shapes of large forgings are usually different (e.g. cylindrical columns, rectangular prisms). Forgings of different geometric shapes need to be measured along different dimensions. For rectangular forgings, the lengths primarily need to be measured. A generalized measurement system for different geometric shapes of forgings cannot provide the accuracy of measurement systems targeted at measuring a known shape. Based on the characteristics of the rectangular forgings, a thermal dimensional measurement system is proposed in this paper. The localization, rapid extraction of feature points and method for measuring the dimensions of rectangular forgings are presented. The proposed methods can easily and efficiently extract the feature points of the forging. The experiment results show that the method proposed in this paper has the advantages of high precision and high efficiency, which is appropriate for online measurement.

A new method for registration of heterogeneous sensors in a dimensional measurement system

Registration of multiple sensors is a basic step in multi-sensor dimensional or coordinate measuring systems before any measurement. In most cases, a common standard is used to be measured by all sensors, and this may work well for general registration of multiple homogeneous sensors. However, when inhomogeneous sensors detect a common standard, it is usually very difficult to obtain the same information, because of the different working principles of the sensors. In this paper, a new method called multiple steps registration is proposed to register two sensors: a video camera sensor (VCS) and a tactile probe sensor (TPS). In this method, the two sensors measure two separated standards: a chrome circle on a reticle and a reference sphere with a constant distance between them, fixed on a steel plate. The VCS captures only the circle and the TPS touches only the sphere. Both simulations and real experiments demonstrate that the proposed method is robust and accurate in the registration of multiple inhomogeneous sensors in a dimensional measurement system.

Development of S-Parameter Calibration System for Type-N, $75-\Omega$ Connector Below 12 GHz

This paper describes a primary scattering parameter (S-parameter) measurement standard and a calibration system based on precision coaxial airlines with Type-N, $75-\Omega $ (Type-N75) connectors. The primary standard and calibration system can calibrate a device under test at frequencies below 12 GHz. The dimensional measurements of the airline diameters and lengths are performed accurately using the standard dimensional measurement system at the National Metrology Institute of Japan. Furthermore, a small insertion loss was measured in the microwave-frequency regions. The primary standard and the calibration system are the first of their kinds to undertake the establishment of S-parameter measurement traceability below 12 GHz for Type-N75 [1] coaxial lines, to the best of our knowledge.

Triceps-sparing extra-articular step-cut olecranon osteotomy for distal humeral fractures: an anatomic study

This anatomic study investigated the distal humeral articular surface exposure achievable through a triceps-sparing oblique extra-articular osteotomy of the olecranon with a step-cut modification compared with the anconeus flap transolecranon apex distal chevron osteotomy. In addition, the bone contact surface areas of the osteotomized surfaces after transolecranon and extra-articular osteotomies were compared. Seven pairs of fresh adult cadaveric elbow joints were examined. Each of the right elbows underwent triceps-sparing extra-articular step-cut olecranon osteotomy (SCOOT) with an anconeus flap, and the left elbows underwent the anconeus flap transolecranon apex distal chevron osteotomies (CO). The articular surface exposed by each of the osteotomy techniques was then digitally analyzed using a 3-dimensional measurement system. The bone contact surface area of the osteotomized surfaces was also assessed. The percentage of total joint exposed by the SCOOT group was less than the CO group (SCOOT: 64% ± 3% vs. CO: 73% ± 3%; P = .002). There was significantly greater bone contact surface area of the osteotomized surfaces in the SCOOT group compared with the CO group (SCOOT: 1172 ± 251 mm2 vs. CO: 457 ± 133 mm2; P = .002). The triceps SCOOT procedure with an anconeus flap provides excellent distal humeral articular surface exposure with the added benefit of a substantially increased (2.6-times) bone contact surface area of the osteotomized surfaces.