3D Scanning Measurement Research Articles

Digital bead modeling for wire-arc directed energy deposition

Prediction of 2D cross-section and full 3D geometry for stacked weld beads is critical for the outcome of wire-arc directed energy deposition (DED) parts; however, most additive path planning software packages model beads as extrusions of a rectangle. Weld beads are not rectangular, and the resulting shape is dependent upon physics effects at the moment of deposition. Physics phenomena such as the geometry of the underlying surface, the heat input of the welding mode, and the direction of gravity contribute to bead shape. This paper presents a novel implicit modeling method that discretizes a 2D area or 3D volume of space into pixels or voxels and constructs fields based on these physics phenomena. The fields are combined using a weighting scheme trained on 3D scan measurements of welds and wire-arc DED prints. Pixels or voxels are added until the known amount of deposited volume has been achieved. Thereby, a strong conservation of mass principle is applied to the process. Utilizing machine learning techniques, the present model can be trained on a database of scans allowing for the representation of a wide variety of prints. Results show that this method can produce predictions with realistic bead morphology and sub-millimeter form error.

Combined 3D scanning measurement method based on guidance of full-space laser positioning system

Combined 3D scanning measurement method based on guidance of full-space laser positioning system

High accuracy calibration method for multi-line structured light three-dimensional scanning measurement system based on grating diffraction.

Multi-line structured light three-dimensional (3D) scanning measurement system enables to obtain the richer 3D profile data of the object simultaneously during one frame, ensuring high accuracy while structured light is deformed for the modulation by the object. Nevertheless, current calibration methods cannot fully take advantage of its high precision. In this paper, a fast and high-accuracy 3D measurement system based on multi-line lasers with a spatially precise structure via integrating a diffraction grating was proposed. This helps achieve precise calibration results of the light planes by introducing spatial constraint relations of the diffractive light, thus improving measurement accuracy. The operating principle and the workflow of the proposed system were described in detail. The measurement accuracy of the developed prototype was verified through contrastive experiments. At a working distance of 400 mm, the results show that the root mean square error (RMSE) of the proposed system is 0.083 mm, which is improved by 37.6% compared to the traditional calibration method of light planes for the ranging system. The system utilizing a grating that facilitates the integration of the device has great application value.

Erosion-Corrosion Failure Analysis of a Mild Steel Nozzle Pipe in Water-Sand Flow.

Several leaks appeared in a mild steel (MS) pipe jet nozzle installed in a direct impact test rig after a few months of operation in erosive flow at the Centre for Erosion-Corrosion Research. The locations of perforation leaks were primarily upstream, but severe wall thinning was also noticed adjacent to the exit section. In this paper, a failure analysis was carried out on the leaking of a pipe jet nozzle, and the results are discussed in detail. The investigation carried out includes visual observation, scanning electron microscopy, 3D scanning, energy-dispersive spectroscopy, and laser profilometry measurements. In addition, numerical simulations based on computational fluid dynamics (CFD) and the discrete phase model (DPM) were conducted to investigate the root cause of the failure of leaks in the pipe jet nozzle. Further CFD-DPM simulations were performed on three different pipe jet designs for liquid-solid flow conditions, and were compared to find an alternative design to prevent the failure of the pipe jet nozzles. It was found that the increase in turbulence along with multiple impacts of particles on the wall generate leaks and cracks in the pipe jet nozzle. Moreover, the CFD-DPM showed a five-fold reduction in the maximum erosion rate; this was observed in the replacement of failed pipes with the proposed alternative nozzle pipe design featuring a chamfer reducer section. The CFD-DPM analysis of all geometric configurations showed that alteration of reducer section design has the greatest impact on erosive wear mitigation.

Investigation of size-independent fracture energy of cementitious materials by quantifying the deformation energy

As an intrinsic parameter, the fracture energy of a material with a designated mix proportion should be constant; however, the size effect considerably affects the research on fracture energy. Deformation energies outside the fracture surface consume some of the input energy, which was ignored, and these were found to be the main causes of the size effect on fracture energy. In this study, the fracture energies of samples with different sizes were investigated, and the fracture areas were accurately measured using a 3D scanning measurement system (SMS). The internal volumetric strains were then indirectly obtained by DIC, and a calculation method to determine the deformation energy of a cementitious material was proposed based on the obtained volumetric strains. The results showed that the fracture energies of samples of different sizes, when deformation energy was considered, were approximately consistent. Thus, the size effect problem on fracture energy was effectively resolved.

Efficiency of non-operative management for pectus deformities in children using an X-ray-free protocol.

To explore the correlation between the Haller index (HI), the external depth of protrusion, and the external Haller index (EHI) for both pectus excavatum (PE) and carinatum (PC). To assess the variation of the HI during this first year of non-operative treatment for pectus deformities in children. From January 2018 to December 2022, all children treated for PE by vacuum bell and for PC by compression therapy at our institution were evaluated by external gauge, 3D scanning (iPad with Structure Sensor and Captevia-Rodin4D), and magnetic resonance imaging (MRI). The main objectives were to assess the effectiveness of the treatment during the first year and to compare the HI determined by MRI to the EHI evaluated with 3D scanning and external measurements. The HI determined by MRI was compared to the EHI evaluated with 3D scanning and external measurements at M0 and M12. 118 patients (80 PE and 38 PC) had been referred for pectus deformity. Of these, 79 met the inclusion criteria (median age 13.7 years, 8.6-17.8). There was a statistically significant difference in the external measurements of the depth for PE between M0 and M12: 23.0 mm ± 7.2 vs 13.8 mm ± 6.1, respectively; p < 0.05 and for PC 31.1 mm ± 10.6 vs 16.7 mm ± 8.9, respectively; p < 0.01. During this first year of treatment, the reduction in the external measurement increased more rapidly for PE compared with PC. We found a strong correlation between the HI by MRI and the EHI by 3D scanning for PE (Pearson coefficient = 0.910, p < 0.001) and for PC (Pearson coefficient = 0.934, p < 0.001). A correlation between the EHI by 3D scanning and the external measurements by profile gauge was found for PE (Pearson coefficient = 0.663, p < 0.001) but not for PC. Excellent results were observed as soon as the sixth month for both PE and PC. Measurement of protrusion is a reliable monitoring tool at clinical consultation but caution is required for PC as it does not appear to be correlated to the HI by MRI.

Influence of topology optimization parameters on the mechanical response of an additively manufactured test structure

Topology Optimization (TO) determines a material distribution within a domain under given conditions and design constraints, and generally generates complex geometries as a result. Complementary to TO, Additive Manufacturing (AM) offers the ability to fabricate complex geometries which may be difficult to manufacture using traditional techniques such as milling. AM has been used in multiple industries including the medical devices area. Hence, TO may be used to create patient-matched devices where the mechanical response is catered to a particular patient. However, during a medical device regulatory 510(k) pathway, demonstrating that worst-cases are known and tested is critical to the review process. Using TO and AM to predict worst-case designs for subsequent performance testing may be challenging and does not appear to have been thoroughly explored. Investigating the effects of TO input parameters when AM is employed may be the first step in determining the feasibility of predicting these worst-cases.In this paper, the effect of selected TO parameters on the resulting mechanical response and geometries of an AM pipe flange structure are investigated. Four different input parameters were chosen in the TO formulation: (1) penalty factor, (2) volume fraction, (3) element size, and (4) density threshold. Topology optimized designs were fabricated using PA2200 polyamide and the mechanical responses (reaction force, stress, and strain) were observed through experiments (universal testing machine and 3D Digital Image Correlation) and in silico environments (finite element analysis). In addition, 3D scanning and mass measurement were performed to inspect the geometric fidelity of the AM structures. A sensitivity analysis is performed to examine the effect of each TO parameters. The sensitivity analysis revealed mechanical responses can have non-monotonic and non-linear relationships between each tested parameter.

Efficient 3D scanning measurement system based on asymmetric trinocular vision and a multi-line laser.

The laser scanning measurement system has a pivotal role in precision measurement thanks to the non-contacting and low-cost advantages, but traditional methods and systems are inadequate in terms of accuracy, efficiency, and adaptability. In this study, an efficient 3D scanning measurement system based on asymmetric trinocular vision and a multi-line laser is developed to improve the measurement performance. The system design, working principle, and 3D reconstruction method are explored, as well as the innovation of the developed system. Furthermore, an efficient multi-line laser fringes indexing method is presented based on K-means ++ clustering and hierarchical processing to improve processing speed with guaranteed accuracy, which is the key point of the 3D reconstruction method. Various experiments are conducted to verify the capability of the developed system, and the results show that the developed system fulfills measurement needs in adaptability, accuracy, effectiveness, and robustness. The developed system achieves better results than commercial probes for complex measurement conditions, and measurement precision can be achieved to within 18µm.

Development of automatic 3D body scan measurement line generation method

PurposeThis research aimed to develop an automatic 3D body measurement line generation method that reduces errors induced by diverse body shapes and incomplete scan areas.Design/methodology/approachThree-dimensional body scan data from the 5th Size Korea database were used. Measurement extraction methods were developed for each measurement; chest girth, underbust girth, armscye girth and neck base girth.FindingsThe research showed that the method adopted in this study enhanced the accuracy of the scan measurements for various body shapes and incomplete scan data. The authors verified the accuracy of the developed methods for various body shapes by comparing the scan measurement against manual measurement.Originality/valueThe automatic 3D body measurement line generation algorithms developed for various human body shapes will improve the reliability and accuracy of 3D body scan measurement program. Also. it will be of practical use in human-size-related production processes.

Corresponding measurement-based patternmaking method for leggings using three-dimensional body scanning technology

Based on 3D body scanning, this study developed the corresponding measurement-based patternmaking (CMP) method for leggings that could systematically provide an excellent fit and control tightness for different body parts. The CMP method for leggings was qualitatively validated by comparing the fit suitability of the produced leggings prototypes through a wear test. The results suggest that the CMP method is an option to design leggings with outstanding suitability in terms of appearance satisfaction, size satisfaction, compression satisfaction, usefulness in movement, ease of movement, ease in donning and doffing for different body parts. In particular, the graduated application percentage (GAP) provided an advantage in usefulness in movement, while the fixed application percentage (FAP) showed an advantage in ease in donning and doffing. As such, this study suggests selecting the CMP method of the application percentage (AP) depending on the purpose of use. This study demonstrated that the proposed method ensured validity in directly implementing a leggings pattern with 3D body scanning and body measurement alone.

Investigation of garments fit for 20-30 aged Bangladeshi men’s

In this research the author tries to find out the traditional pattern making error comparing with 3D scanning measurement data to test fit and balance of make to order garments. At first the author select only men’s classic shirt to evaluate the traditional error for make to order item. After analyzing BG-WG and Bust/Chest typical body sizes are selected to develop block to test factor affecting on fit and balance on real body with garment scanning. Using pattern block of typical body shape the author tries to find out the fit for regular shirt in order to find balanced and fit garment for real bodies. After investigating the pattern block and shape evaluate the adaption fit and balance for each customer. All the resulted data can be implementing by any fashion designer and pattern maker to overcome the traditional error to ensure the fit criteria for the customer.

Classification of high-throughput phenotyping data for differentiation among nutrient deficiency in common bean.

The development of automated, image-based, high-throughput plant phenotyping enabled the simultaneous measurement of many plant traits. Big and complex phenotypic datasets require advanced statistical methods which enable the extraction of the most valuable traits when combined with other measurements, interpretation, and understanding of their (eco)physiological background. Nutrient deficiency in plants causes specific symptoms that can be easily detected by multispectral imaging, 3D scanning, and chlorophyll fluorescence measurements. Screening of numerous image-based phenotypic traits of common bean plants grown in nutrient-deficient solutions was conducted to optimize phenotyping and select the most valuable phenotypic traits related to the specific nutrient deficit. Discriminant analysis was used to compare the efficiency of groups of traits obtained by high-throughput phenotyping techniques (chlorophyll fluorescence, multispectral traits, and morphological traits) in discrimination between nutrients [nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), and iron (Fe)] at early and prolonged deficiency. Furthermore, a recursive partitioning analysis was used to select variables within each group of traits that show the highest accuracy for assigning plants to the respective nutrient deficit treatment. Using the entire set of measured traits, the highest classification success by discriminant function was achieved using multispectral traits. In the subsequent measurements, chlorophyll fluorescence and multispectral traits achieved comparably high classification success. Recursive partitioning analysis was able to intrinsically identify variables within each group of traits and their threshold values that best separate the observations from different nutrient deficiency groups. Again, the highest success in assigning plants into their respective groups was achieved based on selected multispectral traits. Selected chlorophyll fluorescence traits also showed high accuracy for assigning plants into control, Fe, Mg, and P deficit but could not correctly assign K and N deficit plants. This study has shown the usefulness of combining high-throughput phenotyping techniques with advanced data analysis to determine and differentiate nutrient deficiency stress.

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.

Continuous zoom compound eye imaging system based on liquid lenses.

In this paper, a continuous zoom compound eye imaging system based on liquid lenses is proposed. The main imaging part of the system consists of a liquid compound eye, two liquid lenses and a planar image sensor. By adjusting the liquid injection volumes of the liquid compound eye and liquid lenses, the system can realize continuous zoom imaging without any mechanical movement of imaging components. According to the results of experiments, the paraxial magnification of the target can range from ∼0.019× to ∼0.037× at a fixed working distance. Moreover, the system can realize continuous focusing at a fixed paraxial magnification when the working distance ranges from ∼200mm to ∼300mm. Compared with the traditional artificial compound eye imaging systems, the proposed system increases the adjustability and matches the variable image surfaces of the liquid compound eye to a planar image sensor. The aspherical effects of the liquid compound eye and liquid lenses are also considered in the design of the system. The system is expected to be used for imaging in various scenes, such as continuous zoom panoramic imaging, 3D scanning measurement and so on.

Using termination points and 3D visualization for dimensional control in prefabrication

To increase productivity, quality, and safety, heavy industrial construction projects are increasingly adopting prefabrication and modularization techniques. This shift, in turn, has resulted in fabrication shops fabricating more complex assemblies with tighter tolerances. However, most measurement in these shops is conducted using manual hand measurement tools, which can be costly and is known to cause significant rework due to geometric noncompliance of termination points in particular. Termination points are defined as the coordinate system points where assemblies connect or are constrained. Automated, 3D-scanning measurement and visualization systems can potentially be accurate, repeatable, and objective sources of termination point data. In this paper, a new framework for classification and calculation of termination points is presented that is based on automated, 3D-scanning measurement and visualization. The utilization of the framework enables fabrication shops and project owners to adopt effective 3D measurement solutions. To investigate the usefulness of the defined framework, a termination-point-based scan-vs-BIM method is developed for objects with circular cross sections, such as pipe spool assemblies. The method was validated in an industrial-scale experimental study. The study demonstrated that the new framework can be used to develop applications that are more accurate and provide superior visualization to craft workers during fabrication, and thus potentially improve productivity and reduce rework.

Automatic Measurement of Neutral Foot Posture Using Three-Dimensional Scanning

The Rearfoot Angle (RFA) is the most commonly method used for foot posture assessment, and it is also a method for evaluating the subtalar joint neutral foot posture. However, orthopedists and researchers often meet trouble for the measurements of the RFA and neutral foot posture due to lacking measurement with automation and objectivity. In general, the RFA was measured using a goniometer to align with manual markers on the foot. The purpose of this study implements the automatic computing of leg angle, foot angle, and RFA by the foot model using Three-Dimensional (3D) scanning. This study contributes to the algorithms to The purpose of this study implement the automatic and objective computing of leg angle, foot angle, and RFA by the foot model using 3D scanning. The automatic calculation on leg angle, foot angle, and neutral foot posture has been created, test, and validated completely in this study. There are two algorithm methods proposed to determine the midpoint on the leg or foot outline. The midline has been computed by linear regression through five midpoints. The leg and foot angles are calculated by the tibial and calcaneal midlines, respectively. Through the subject standing on eversion foot platforms, the neutral posture of the foot can be computed by the leg and foot angles determined by the 3D model scanned of the foot with various tilt angles. The determinations of the midpoint and midline have been demonstrated algorithm by MATLAB. Based on comparing with the goniometer measured, selecting the midpoint algorithm of the limit points and the lowest point methods to determine the tibial and calcaneal midlines respectively would carry out better results. The foot 3D scanning measurement proposed in this study has been tested and validated from the goniometer. This study can determine the leg angle, foot angle, and neutral foot postures for a subject with normal weight status, but be not suitable for that with obese weight status. In the future, this study can provide guidance for foot posture assessment and personal insoles design.

Performance and thermoregulation of Dutch Olympic and Paralympic athletes exercising in the heat: Rationale and design of the Thermo Tokyo study: The journal Temperature toolbox

ABSTRACT The environmental conditions during the Tokyo Olympic and Paralympic Games are expected to be challenging, which increases the risk for participating athletes to develop heat-related illnesses and experience performance loss. To allow safe and optimal exercise performance of Dutch elite athletes, the Thermo Tokyo study aimed to determine thermoregulatory responses and performance loss among elite athletes during exercise in the heat, and to identify personal, sports-related, and environmental factors that contribute to the magnitude of these outcomes. For this purpose, Dutch Olympic and Paralympic athletes performed two personalized incremental exercise tests in simulated control (15°C, relative humidity (RH) 50%) and Tokyo (32°C, RH 75%) conditions, during which exercise performance and (thermo)physiological parameters were obtained. Thereafter, athletes were invited for an additional visit to conduct anthropometric, dual-energy X-ray absorptiometry (DXA), and 3D scan measurements. Collected data also served as input for a thermophysiological computer simulation model to estimate the impact of a wider range of environmental conditions on thermoregulatory responses. Findings of this study can be used to inform elite athletes and their coaches on how heat impacts their individual (thermo)physiological responses and, based on these data, advise which personalized countermeasures (i.e. heat acclimation, cooling interventions, rehydration plan) can be taken to allow safe and maximal performance in the challenging environmental conditions of the Tokyo 2020 Olympic and Paralympic Games.

Assessment of pedicle size in patients with scoliosis using EOS 2D imaging: a validity and reliability study

PurposeFree-hand pedicle screw insertion methods are widely used for screw insertion during scoliosis surgery. Preoperative knowledge about the pedicle size helps to maximize screw containment and minimize the risk of pedicle breach. Radiographs taken by a biplanar low-dose X-ray device (EOS) have no divergence in the vertical plane. The criterion validity and reliability of preoperative EOS images for pedicle size measurements in patients with idiopathic scoliosis (IS) was investigated in this study.MethodsSixteen patients who underwent surgical treatment for IS were prospectively included. Intra- and extracortical pedicle height and width measurements on EOS images were compared with reconstructed intra-operative 3D images of the isthmus of included pedicles. Secondly, intra- and interobserver reliability of pedicle size measurements on EOS images was determined.ResultsThe total number of analyzed pedicles was 203. The correlation between the EOS and 3D scan measurements was very strong for the intra- and extracortical pedicle height and strong for the intra- and extracortical pedicle width. There are, however, significant, but likely clinically irrelevant differences (mean absolute differences < 0.43 mm) between the two measure methods for all four measurements except for extracortical pedicle height. For pedicles classified as Nash–Moe 0, no significant differences in intra- and extracortical pedicle width were observed. Both intra- and interobserver reliability was excellent for all pedicle size measurements on EOS images.ConclusionThe results of this study indicate a good validity and reliability for pedicle size measurements on EOS radiographs. Therefore, EOS radiographs may be used for a preoperative estimation of pedicle size and subsequent screw diameter in patients with IS.

DEVELOPMENT OF A BOOT-TREE MOLD FOR MANUFACTURING RIDING BOOTS

The production of such footwear as riding boots requires additional equipment like a special mold for the formation of bootlegs, which are made using intermediate frame parts to ensure rigidity and preserving shape. The special mold of riding boots is a stylized shape of the leg from its foot to knee. The lower part corresponding to the shoe last is designed based on the parameters of the average foot, taking into account the requirements of biomechanics, physiology, and aesthetic features of the shoe style. The upper part repeats the parameters of the shin and has a specifi c asymmetrical shape, which ensures a stylish and perfect form of the riding boot. To obtain the initial data for designing the mold, there were performed anthropometric measurements of the shins of young women whose feet sizes correspond to the average ones in the selected sample. Designing of the lower part of the mold was carried out on the basis of the average parameters of the foot in Crispin LastMaker software complex using the method of reverse engineering. Designing of the general shape was performed in the PowerShape software environment by means of the features of surface, solid, and hybrid modeling. This type of boots must be made with several width-girth parameters, and the possibility to make boots with diff erent designs must be provided. Therefore, in order to e ff ectively use the molding means (a boot-tree), in the work, there was proposed the transforming mold, which allows making boots of diff erent widths and with diff erent shapes of the toe part due to its struc ture consisting of four parts changing the relative position and individual elements due to which it is possible to achieve multipurpose usage. Objective. Development of an improved shape, design, and method of designing a boot-tree molding means based on the foot 3d scan and shin measurements using the features of modern CAD software.Topicality of the work is based on the need to equip footwear production with the advanced lasts and molding means taking into account the requirements of ergonomics and fashionable design. Novelty. The proposed structure of the boot-tree developed on the basis of foot measurements is designed using a combination of reverse and direct modeling of the shape, which allows achieving the ideal and unique 3D shape combining ergonomic features and beautiful design. Such design method allows using the available digital equipment to obtain the initial data.

The Geometric Accuracy of Complex Surface Using 5-Axis Turn-mill Machine

This paper presents an analysis model for geometric accuracy measurement of marine propeller blades. Geometric accuracy of marine propeller models, which has been finished by machining processes are measured and analyzed using GOM 3D photo-scanning peripheral and software. The methods we used are firstly, marine propeller blades are scanned by GOM Scanner and then the effects of cutting parameters, that is step-over variation on the geometric accuracy are investigated. Inspection of geometric accuracy is performed by comparing the result of 3D scanning measurement of finished propeller with CAD design data using GOM Inspect 2016 software. The results showed that greater step-over value, the deviation value tends to be smaller. Finally, this method is proven effective in measuring by producing similar trends at two measurement position points.