This article presents the use of TLS (LiDAR) measurement for the evaluation of the technical conditions of a historic building. A FARO M70 laser scanner was used in the study. The measurements was ...taken as an RCP point cloud. The measurement allowed to partially determine the cause of the building damage. The performed measurement allows to propose a precise solution that could be pre-fabricated. The study shows the usefulness of TLS in building diagnostics. Improper measurement could lead to a wrong solution and a certain degree of uncertainty.
This paper presents methods for continuous condition monitoring of railway switches and crossings (S&C, turnout) via sleeper-mounted accelerometers at the crossing transition. The methods are ...developed from concurrently measured sleeper accelerations and scanned crossing geometries from six in situ crossing panels. These measurements combined with a multi-body simulation (MBS) model with a structural track model and implemented scanned crossing geometries are used to derive the link between the crossing geometry condition and the resulting track excitation. From this analysis, a crossing condition indicator Cλ1-λ2, γ is proposed. The indicator is defined as the root mean square (RMS) of a track response signal
that has been band-passed between frequencies corresponding to track deformation wavelength bounds of λ1 and λ2 for the vehicle passing speed (
=
/ λ). In this way, the indicator ignores the quasi-static track response with wavelengths predominantly above λ1 and targets the dynamic track response caused by the kinematic wheel-crossing interaction governed by the crossing geometry. For the studied crossing panels, the indicator C1-0.2 m, γ (λ1=1 and λ2=0.2) was evaluated for
=
,
, or
as in displacements, velocities, and accelerations, respectively. It is shown that this condition indicator has a strong correlation with vertical wheel-rail contact forces that is sustained for various track conditions. Further, model calibrations were performed to measured sleeper displacements for the six investigated crossing panels. The calibrated models show (1) a good agreement between measured and simulated sleeper displacements for the lower frequency quasi-static track response and (2) improved agreement for the dynamic track response at higher frequencies. The calibration also improved the agreement between measurements and simulation for the crossing condition indicator demonstrating the value of model calibration for condition monitoring purposes.
Firefighters have reported their protective boots to be bulky and ill-fitting, which they believe restrict the lower body movement on the unpredictable fireground. This study used 3D foot scanning to ...compare the shape of firefighters' feet to the general population, the shape of female firefighters’ feet to males, and the impact of the heavy fire gear on foot shape. The results found the foot breadth of firefighters was larger than the general population and the feet of female firefighters were slimmer than males. Furthermore, it revealed that the feet of firefighters became longer, wider, and flatter when bearing the weight of fire gear. Protective boots should be designed based on the foot shape and dimensions of the actual population, with consideration of sex differences and the impact of weight-bearing for their safety.
•Foot breadth of U.S. firefighters was larger than the general population on average.•Female firefighters have narrower foot breadth proportional to foot length than male firefighters.•Heavy turnout ensemble of firefighters makes the feet of the wearer longer, wider, and flatter.
A crucial activity in architectural and archaeological conservation research
is the process of synthesising information in which the researcher records
collected field data in the form of a planar ...drawing. This labour-intensive stage is
significantly improved by automated systems which support the measurement
work. Some of these are programs that convert sets of photographs into virtual
and spatial models.
The author compares the reasonably priced software options, shares the
experience which was gathered during their use and presents the results of
the research. The paper also presents the economic aspect and practical
examples and highlights the development potential of these tools.
In dentistry, clinical wear is typically measured by superimposition of plaster replica scans of the patient's actual and baseline situation. Intraoral scanning could save time and circumvent replica ...fabrication and associated errors. However, intraoral scanners are made for commercial use without the possibility to implement comprehensive user-specific settings. Analysis of exported stl-data is, in general, executed with commercial quality control software.
This study investigated the effect of mesh inhomogeneities on distance measurements based on target surfaces generated by different scanners and parameter settings. To quantify errors, an analytical solution for mean value and standard deviation of evenly distributed distance measurements for a spherical cap situation (resembling either a worn cusp or a wear track in a once flat surface) was derived. In vitro experiments with scans of precise spherical moulds gradually reduced in height complemented the investigation.
Due to non-weighted statistics in the quality control software, errors increased with increasing mesh inhomogeneity. Worst results were given for intraoral scans with mean relative errors of up to 13.2% and 20.5% for mean value and standard deviation of the distributed distance measurements. Homogeneous remeshing of the intraoral scan surfaces could almost eliminate these unwished effects.
•Analytical solution as reference•For large tilts between opposion surface areas, correct choice of the target surface is important•More pronounced mesh inhomogeneities caused larger errors in statistical distance measurement parameters•For tests with spherical moulds, evaluations based on scans with an intraoral scanner performed worst•Unwished statistical effects could be eliminated by high-quality homogeneous remeshing
Three-dimensional (3D) printing, or additive manufacturing, has been increasingly used in many fields, including the medicine, food, sensing, metal, automotive, and construction industries. ...Regardless of its growing applications, there are few of methods, guidelines, and specifications for measuring and quantifying the qualities of 3D printed objects. This is particularly so for objects those are too small, too large, and/or too fragile to be handled manually. In this study, for the first time, a non-contact, and non-destructive measurement method, a 3D structured light scanning system (3D-SLSS), was employed for evaluating the printing qualities of clay objects with different levels of visual defects (e.g., roughness and distortion). 3D scanned images of these clay samples were developed using 3D-SLSS. Then, they were sliced along their sides (perpendicular to the base) to generate a number of two-dimensional (2D) plots, from which various parameters (e.g., sample total height Htotal, outer diameter DMouter, layer thickness TL, layer width, (WL, surface angle Sα, semi-cross-sectional area XA, and surface roughness R) were measured. These measurements were then compared with the designed values. The percentages of the differences between the measured and designed values were used to develop a diagnosed area of deficiency, by which the overall qualities of the printed samples were quantified. The results illustrated that all the printed samples exhibited certain differences between their measured and designed values, even for those that appeared well printed. Compared with the designed object, the printed samples generally had reduced total height, diameter, and layer thickness; increased layer width; measurable distortion; and visible surface roughness. Many of these were largely because the freshly printed clay deformed under the weight of the layers above. The distortion angle and area are two necessary parameters for quantifying the degree of distortion of a printed sample. The diagnosed area of deficiency can well describe the overall qualities of the printed samples. 3D-SLSS is a relatively simple, fast, and inexpensive characterization method. Moreover, it can be conveniently extended to various industries for quality control of diverse 3D printing products.
Laser range scans of urban areas have a distinctive geometry dominated by facade and ground planes and repetitive regular fenestration. Detection of these ubiquitous features provides profound ...insights into the scene. We present a novel method for detecting major planes and repetitive architectural features. Armed with this knowledge we illustrate its application in compression and registration of range scans. What is more our algorithm operates online, processing the scan as it is retrieved by the scanner. This realtime approach opens up new possibilities in range data segmentation, compression and registration.
In this study, the effectiveness of an experimental clinical technique for the reproduction of attachments during an orthodontic treatment with clear aligners was evaluated using a new index (CorAl) ...for quality assessment that exploits the differential entropy of point clouds. The procedure involves the use of a pre-drilled template and a second pre-loaded template with a high-viscosity composite and is compared with the standard technique. Attachment planning was conducted on four prototypes of dental arches with extracted teeth which were divided into two groups according to the proposed operating procedures. Digital scans were utilized to capture dental impressions for both the purposes of virtual planning and to reproduce the clinical outcomes post-procedure. The point clouds obtained after the reproduction of the attachments were aligned with those from the virtual planning, and the deviation analysis was conducted using the quality index of the CorAl method. Though no significant discrepancies were found among the groups regarding morphological flaws, detachments, or maximum defect values, the differential entropy analysis revealed that the experimental technique offers good alignment in attachment placement. The outcome supports that the innovative procedure of the clinical reproduction of attachments proved to be reliable and operationally simple, with additional benefits derived from using the CorAl index. The advantages of CorAl include the use of a single comparison index, no problem of comparison commutativity, noise immunity, low influence from the presence of holes, and point cloud densities. This allows for the drawing of quality maps that show areas with the highest deviation.
Modeling the shape of the scalp and face is essential for the design of protective helmets and other head-borne equipment. However, head anthropometry studies using optical scanning rarely capture ...scalp shape because of hair interference. Data on scalp shape is available from bald men, but female data are generally not available. To address this issue, scalp shape was digitized in an ethnically diverse sample of 100 adult women, age 18–59, under a protocol that included whole head surface scanning and scalp measurement using a three-dimensional (3D) coordinate digitizer. A combined male and female sample was created by adding 3D surface scans of a similarly diverse sample of 80 bald men. A statistical head shape model was created by standardizing the head scan data. A total of 58 anatomical head landmarks and 12 head dimensions were obtained from each scan and processed along with the scans. A parametric model accounting for the variability of the head shape under the hair as a function of selected head dimensions was developed. The full-variable model has a mean shape error of 3.8 mm; the 95th percentile error was 7.4 mm, which were measured at the vertices. The model will be particularly useful for generating a series of representing a target population as well as for generating subject-specific head shapes along with predicted landmarks and dimensions. The model is publicly available online at http://humanshape.org/head/.
Display omitted
•A statistical head shape model based on a large male and female 3D head scans with accurate scalp surface data.•3D head shape measurements data were statistically analyzed using principal component analysis and regression analysis.•Subject-specific bald head shapes can be generated using an optimal set of anthropometric variables.•A spatial error metric was provided to account for the geometric discrepancy between predictions and actual measurements.
This study focuses on the body shape of Vietnamese women, collected from large-scale measurement data, to establish a bra size system for mature Vietnamese women aged 18 to 55. Measurement data was ...collected from 1100 subjects using a 3D scanner. During the data collecting process, 18 measurements at the chest area were classified and used for the research and analysis. Data analysis is performed by the Principal Component Analysis (PCA) method and Numerical Analysis. Mean and median values are used to understand the central tendency of sizing charts. Standard deviation is leveraged to derive size categories, intervals and separate the outliers. Two size-matching solutions are implemented to find the optimal sizing system. The result found a 26 sizes bra system which is a combination of 5 band sizes and 6 cup sizes, with a response rate of 98.27% based on the primary dimensions of bust girth and underbust girth. The study's results were compared with the bra size systems of some countries in Asia and around the world, showing that differences in body shape have led to differences in the systems. the number of sizes. The ultimate goal of this research is to systematically establish a data database with local characteristics and significance that will contribute to sustainable development in academic research, industrial production, application, commercial activities, and service design in the future. The results of this study are meaningful for bra manufacturers in the Vietnamese market and for women in selecting suitable bras for their somatotype.
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