Scanning Device Research Articles

Finite Element Simulation and Experimental Validation of Welding Distortion of Fillet Welded T-joints

This research presents a numerical simulation for predicting welding induced distortion with an experimental validation. Three experimental specimens of S355J2G3 structural steel with thicknesses of 3mm, 5mm and 8mm have been used as test cases. In order to validate the results an experiment was set up to gain detailed information about distortions occurring in single fillet welded T-joints. The non-linear heat transfer analysis is used and heat source is modeled with the Goldak’s double ellipsoidal distribution by using SYSWELD in the gas metal arc welding (GMAW) process. This study employs the finite element (FE) method to evaluate residual stresses and angular distortions. A series of FE simulations and corresponding experiments are performed to evaluate the depth of penetration in the cross sections, angular distortions that occur after welding, temperature distribution, and residual stresses. A coordinate measuring machine and a 3D non-contact scanning device are used to measure the angular distortions and displacement distributions, respectively. The results show that controlling welding process via simulations can significantly enhance the performance of process, and help to minimize distortions and decrease costly design errors.

Development of sensitive and specific loop-mediated isothermal amplification combined with lateral flow device for the rapid detection of hepatitis B virus infection.

HBV standard plasma panels and donor plasma specimens were used to evaluate the assay. HBV DNA was extracted by using QiAamp DNA Blood Mini Kit. Amplification was carried out at constant temperature 63°C for 60min. LAMP end products were analyzed by using ESE LAMP tube scanner, gel electrophoresis, UV-lamp, and lateral flow device. HBV-LAMP-LFD assay revealed sensitivity of 92% (138/150) of HBV positive plasma specimens. Specificity of HBV-LAMP-LFD was calculated 100%. Our study concludes that HBV-LAMP-LFD is rapid, easy to use, sensitive, and specific point-of-care diagnostic assay for the detection of hepatitis B virus in blood samples. This assay can be used in resource-limited settings as well as in HBV endemic areas.

Контроль и регулирование влажности бумажного полотна

Product quality is a key indicator of the positive outcome of pulp and paper production. Moisture content is one of the main paper quality characteristics. The moisture profile across the paper web width shows possible shortcomings of the process equipment which, if corrected, will improve the consumer properties of paper and enhance economic efficiency. The research aims to assess whether the moisture content measurement results meet the requirements of the process regulations in the steady-state and transient modes of paper machine operation as well as the uniformity of the moisture profile in the cross direction. Data from the scanning device at high and low resolution were processed using statistical methods in order to assess the quality of the automatic paper web moisture control system. It was determined that in the steady-state mode of paper machine operation the moisture content meets the requirements of the regulations with a confidence probability of 0.95; in the transient mode of operation it exceeds the upper limit by 6 %. It has been found that the automated moisture control system eliminates this fault in 340 s. The coefficient of variation was used as a criterion for evaluating the uniformity of the moisture profile across the paper web width. The hypothesis of a trend line in the moisture profile across the paper web width was confirmed and a trend line equation was obtained using regression analysis techniques. The moisture profile was modeled while eliminating the technological factor that systematically affects the uniformity. It is proven that the elimination of the fault will reduce the coefficient of variation and therefore improve the uniformity of the profile by 41.2 % in the steady-state mode of paper machine operation. In the transition mode of operation the moisture profile improves slightly. The proposed algorithm for studying the moisture profile of paper, its modeling after corrections of the control object can be used in systems for controlling the quality of paper in the transverse direction. For citation: Koryakovskaya N.V., Bederdinova O.I. Monitoring and Control of Paper Web Moisture. Lesnoy Zhurnal [Russian Forestry Journal], 2022, no. 1, pp. 188–204. DOI: 10.37482/0536-1036-2022-1-188-204

Machine Learning in Point of Care Ultrasound.

When a patient presents to the ED, clinicians often turn to medical imaging to better understand their condition. Traditionally, imaging is collected from the patient and interpreted by a radiologist remotely. However, scanning devices are increasingly equipped with analytical software that can provide quantitative assessments at the patient’s bedside. These assessments often rely on machine learning algorithms as a means of interpreting medical images.

Operationalizing the use of TLS in forest inventories: The R package FORTLS

Terrestrial Laser Scanning (TLS) devices show great potential for application in Forest Inventories (FIs) as they are capable of registering high resolution point clouds rapidly and automatically. Nevertheless, operational use of TLS for FI purposes has been hampered by the absence of algorithms for processing the acquired data, particularly in the single-scan mode, as occlusions result in loss of information. The R package FORTLS has been developed to overcome this obstacle, as it automates the processing of single-scan TLS point cloud data for forestry purposes and includes several features that deal with occlusions. FORTLS makes use of the main advantage of the single-scan scenario in FI, thus improving the efficiency of data acquisition and post-processing. All of these features of the FORTLS package are potentially valuable for the operational use of TLS in FIs, in combination with inference techniques derived from model-based and model-assisted approaches.

OCT-Guided Surgery for Gliomas: Current Concept and Future Perspectives.

Optical coherence tomography (OCT) has been recently suggested as a promising method to obtain in vivo and real-time high-resolution images of tissue structure in brain tumor surgery. This review focuses on the basics of OCT imaging, types of OCT images and currently suggested OCT scanner devices and the results of their application in neurosurgery. OCT can assist in achieving intraoperative precision identification of tumor infiltration within surrounding brain parenchyma by using qualitative or quantitative OCT image analysis of scanned tissue. OCT is able to identify tumorous tissue and blood vessels detection during stereotactic biopsy procedures. The combination of OCT with traditional imaging such as MRI, ultrasound and 5-ALA fluorescence has the potential to increase the safety and accuracy of the resection. OCT can improve the extent of resection by offering the direct visualization of tumor with cellular resolution when using microscopic OCT contact probes. The theranostic implementation of OCT as a part of intelligent optical diagnosis and automated lesion localization and ablation could achieve high precision, automation and intelligence in brain tumor surgery. We present this review for the increase of knowledge and formation of critical opinion in the field of OCT implementation in brain tumor surgery.

The correlation between the number of security scanning devices, their capacity and passenger traffic

Background: There is a situation today where the major passenger buildings are lacking the required passenger traffic capacity. This issue has come about as a result of aligning the requirements of the Federal Law on Transport Safety into the buildings design. The problem remains relevant and therefore needs to be addressed.
 Aim: The paper seeks to examine the correlation between the number of transport safety technical devices for scanning passengers bodies and luggage, the device operation time and incoming passenger traffic. This will be done in order to develop recommendations for changing the legislative framework in the field of transport safety and to estimate the advisability of using transport safety technical devices at railway stations, taking into account passenger traffic capacity.
 Methods: The study is based on the theory of multi-channel public service system with an unlimited line. The calculations are based on the assumption, that the peak passenger traffic through the passenger devices is stationary.
 Results: The paper finds the correlation between the number of transport safety technical devices, their capacity and the length of the line of passengers waiting for passing into the passenger buildings.
 Conclusion: The results can be used as a feasibility study of transport safety technical devices, that are installed at the entrance of passenger buildings during their construction, reconstruction or modernization. For the existing buildings the found correlation will help to understand whether it is technically possible to provide the station with the required passenger traffic capacity or it will take capital investments for its reconstruction.

A Comparative Study between Scanning Devices for 3D Printing of Personalized Ostomy Patches.

This papers presents a comparative study of three different 3D scanning modalities to acquire 3D meshes of stoma barrier rings from ostomized patients. Computerized Tomography and Structured light scanning methods were the digitization technologies studied in this research. Among the Structured Light systems, the Go!Scan 20 and the Structure Sensor were chosen as the handheld 3D scanners. Nineteen ostomized patients took part in this study, starting from the 3D scans acquisition until the printed ostomy patches validation. 3D mesh processing, mesh generation and 3D mesh comparison was carried out using commercial softwares. The results of the presented study show that the Structure Sensor, which is the low cost structured light 3D sensor, has a great potential for such applications. This study also discusses the benefits and reliability of low-cost structured light systems.

Characterization of Counter-Surface Substrates for a Laboratory Abrasion Tester (LAT100) Compared with Asphalt and Concrete to Predict Car Tire Performance

Tire performance is determined based on the interaction between the tire and the road as a counter-surface, and is of the utmost importance for driving safety. When studying tire friction and abrasion, the characteristics of the roads/counter-surfaces are crucial. The excitations on the tire come from the road asperities. A proper characterization of the counter-surface texture is, therefore, an absolute necessity in order to optimize tire performance. The present study provides the required knowledge over the counter-surfaces employed as common substrates in a Laboratory Abrasion Tester (LAT100), which are typically based on embedded corundum particles for dry/wet friction and abrasion experiments. All surfaces are scanned and characterized by laser microscopy. The surface micro and macro roughness/textures are evaluated and compared with asphalt and concrete as the real roads by power spectral densities (PSD). The reliability of the high-frequency data based on the device type should be considered carefully. The reliable cut-off wavenumber of the PSDs is investigated based on image analyses on the range of tested frequency for micro and macro textures obtained by optical scanning devices. The influence of the texture wavelength range on the rubber−surface interaction is studied on a laboratory scale.

Domain Adaptation for Object Classification in Point Clouds via Asymmetrical Siamese and Conditional Adversarial Network

Nowadays, researchers have developed various deep neural networks for processing point clouds effectively. Due to the enormous parameters in deep learning-based models, a lot of manual efforts have to be invested into annotating sufficient training samples. To mitigate such manual efforts of annotating samples for a new scanning device, this letter focuses on proposing a new neural network to achieve domain adaptation in 3D object classification. Specifically, to minimize the data discrepancy of intra-class objects in different domains, an Asymmetrical Siamese module is designed to align the intra-class features. To preserve the discriminative information for distinguishing inter-class objects in different domains, a Conditional Adversarial module is leveraged to consider the classification information conveyed from the classifier. To verify the effectiveness of the proposed method on object classification in heterogeneous point clouds, evaluations are conducted on three point cloud datasets, which are collected in different scenarios by different laser scanning devices. Furthermore, the comparative experiments also demonstrate the superior performance of the proposed method on the classification accuracy.

3DBodyNet: Fast Reconstruction of 3D Animatable Human Body Shape From a Single Commodity Depth Camera

Knowledge about individual body shape has numerous applications in various domains such as healthcare, fashion and personalized entertainment. Most of the depth based whole body scanners need multiple cameras surrounding the user and requiring the user to keep a canonical pose strictly during capturing depth images. These scanning devices are expensive and need professional knowledge for operation. In order to make 3D scanning as easy-to-use and fast as possible, there is a great demand to simplify the process and to reduce the hardware requirements. In this paper, we propose a deep learning algorithm, dubbed 3DBodyNet, to rapidly reconstruct the 3D shape of human bodies using a single commodity depth camera. As easy-to-use as taking a photo using a mobile phone, our algorithm only needs two depth images of the front-facing and back-facing bodies. The proposed algorithm has strong operability since it is insensitive to the pose and the pose variations between the two depth images. It can also reconstruct an accurate body shape for users under tight/loose clothing. Another advantage of our method is the ability to generate an animatable human body model. Extensive experimental results show that the proposed method enables robust and easy-to-use animatable human body reconstruction, and outperforms the state-of-the-art methods with respect to running time and accuracy.

СУЧАСНІ МЕТОДИ ІНСПЕКЦІЇ МЕРЕЖ ВОДОВІДВЕДЕННЯ

Underground infrastructural objects such as sewage and water supply networks, which mainly consist of pipes or collectors, are exposed to solid corrosion of concrete and metal, significantly reducing their service life. Today, laser 3D scanning, which allows you to create a three-dimensional map of the pipe's inner surface, is considered one of the promising methods of monitoring sewer networks. Specialists use wheeled robots or aerial platforms with stereo cameras and lasers as devices for laser scanning. The main advantage is that 3D maps can easily detect and quantify structural defects on the pipe's inner surface. Creating a three-dimensional model and its subsequent analysis makes it possible to examine the drainage network in the shortest possible time to find cracks and sealing violations. This model helps to determine the nature of the flow of waste liquids; establish the presence of deposits; assess the degree of wear and corrosion of pipes; insulation condition; integrity and quality of the network after construction or repair. Laser scanning will prevent negative environmental impact, preserve ecology, and not harm the life and health of workers.

Are Digital Methods Sufficiently Successful in Colour Determination for Monolithic All-Ceramic Crowns?

The aim of this study was to compare the visual assessment of tooth shade with the measurement using intraoral scanner (IOS) and spectrophotometer devices. The colour for a single unit implant supported crown was measured visually, using IOS, and spectrophotometer. The results of the digital methods were compared with the visual measurement. A complete colour match with the visual measurement was in 42.9% of cases for IOS, and in 33.3% of cases for spectrophotometry. The match in the colour value, hue, and chroma were in 61.9%, 95.2%, and 66.7% of cases, respectively, for the IOS; and in 61.9%, 61.9%, and 66.7% of cases, respectively, for the spectrophotometry. The differences between the IOS and spectrophotometry were not statistically significant. The most reliable method for tooth colour selection is the visual measurement by an experienced dentist. IOS and spectrophotometer can be used as an alternative method, however in both cases they should be verified using visual measurement.

Accuracy between intraoral and extraoral scanning: Three-dimensional deviation and effect of distance between implants from two scanning methods.

Evaluate the accuracy between the intraoral and extraoral scanning regarding the three dimensional (3D) deviation and distances between the implants, through 2 scanning methods. An in vitro study. An edentulous mandibular model was used to install four implants and abutments, recommending 6 distances between the implants. Scans were performed using an intraoral (SI) and extraoral (SE) scanner for each studied group: Scanning with the scan bodies (SB) and device (SD) (n = 10). The files were imported into a surface evaluation program to assess 3D deviations and measure distances between implants. Precision was assessed as the difference between files (Kruskal-Wallis test), while trueness was assessed from the difference between scans, applying the Wilcoxon and Mann-Whitney test. As for the 3D deviations, SI showed accuracy, for the faces and positions of the implants in relation to the SE, in both scanning methods (P < 0.05). Regarding the capture of distances between implants, the SD scan obtained better trueness than the SB group (P < 0.05). We concluded that the type and scanning methods used did not influence the 3D deviations, while for distances, scanning with the device had better trueness.

Broad-to-Narrow Registration and Identification of 3D Objects in Partially Scanned and Cluttered Point Clouds

The new generation 3D scanner devices have revolutionized the way information from 3D objects is acquired, making the process of scene capturing and digitization straightforward. However, the effectiveness and robustness of conventional algorithms for real scene analysis are usually deteriorated due to challenging conditions, such as noise, low resolution, and bad perceptual quality. In this work, we present a methodology for identifying and registering partially-scanned and noisy 3D objects, lying in arbitrary positions in a 3D scene, with corresponding high-quality models. The methodology is assessed on point cloud scenes with multiple objects with large missing parts. The proposed approach does not require connectivity information and is thus generic and computationally efficient, thereby facilitating computationally demanding applications, like augmented reality. The main contributions of this work are the introduction of a layered joint registration and indexing scheme of cluttered partial point clouds using a novel multi-scale saliency extraction technique to identify distinctive regions, and an enhanced similarity criterion for object-to-model matching. The processing time of the process is also accelerated through 3D scene segmentation. Comparisons of the proposed methodology with other state-of-the-art approaches highlight its superiority under challenging conditions.

32 - A New 3D Volume-Based Method for Assessing Composites Curing Depth

Develop a new method to evaluate the curing depth of conventional and bulkfill composites based on the total volume of cure (VOC) and compare to the ISO 4049 depth of cure standard (DOC) with different mold diameters. A total of 100 samples were made from 2 bulkfill composites and 2 conventional resin-based composites, 25 samples for each material, with 5 samples per diameter of 10 mm, 8 mm, 6 mm, 4 mm, and 2 mm using stainless steel molds of 10 mm length. An individually designed 3D printed frame was attached to a metal plate using stainless steel screws in order to secure a fixed position of the molds in relation to the Valo cordless LED LCU which was clamped to the metal plate with an adjustable arm. ISO DOC was measured according to ISO 4049. Then the domed cylinders were scanned and the VOC% was measured in the Autodesk Meshmixer software using the STL files obtained from the scanned data using a E4D planmeca scanning device. Geomagic software was used for 3D comparison of curing profiles of 10 mm diameter samples. Two-way analysis of variance (ANOVA) and Tukeys test for pairwise comparison was used to analyze the data. A difference plot assembled in the geomagic software was used for 3D comparison of curing profiles ISO 4049 method that measures the center of the specimen does not represent the full potential of the LCU. With a 10 mm ∅ window of the LCU, 10 mm, 8 mm and 6 mm molds give identical results for DOC and VOC%. The difference between the bulkfill and regular composites was significant (p<0.05); bulkfill DOC was between 1.9x (Filtek) and 2.4x (Tetric) higher than for the regular composites. DOC and VOC% are both negatively influenced by smaller mold diameter (p<0.05). The non-homogenous nature of the LCU did not influence the VOC% and DOC. The non-homogenous nature beam profile of the LCU unit had an influence on the 3D curing profiles of the specimen, which can be explained with the higher absorption of the violet light from the composite Most of contemporary LCUs have diameters of the light exiting window >4 mm. since there were significant differences in DOC between ∅ 6 mm and ∅ 4 mm molds. ISO 4049 under-represents the DOC. The influence on the LCUs curing profile on ∅ 6 mm molds should be investigated in the future. The experiment should be repeated with other LCUs than the one used in this study. Results for the ISO DOC and volume of cure percent (VOC %) for different mold diameter samples for 4 materials Filtek Bulkfill one(FBO), Tetric Powerfill(TPF), Filtek Supreme (FS), and Tetric Prime(TP).

An Underwater Pose Estimating Neural Network with 3D Convolutional Layer and Multi-ResNet Using a Multi-Beam Imaging Sonar and a Vertical Scanning Device

An Underwater Pose Estimating Neural Network with 3D Convolutional Layer and Multi-ResNet Using a Multi-Beam Imaging Sonar and a Vertical Scanning Device

Projection-Based Point Convolution for Efficient Point Cloud Segmentation

Understanding point cloud has recently gained huge interests following the development of 3D scanning devices and the accumulation of large-scale 3D data. Most point cloud processing algorithms can be classified as either point-based or voxel-based methods, both of which have severe limitations in processing time or memory, or both. To overcome these limitations, we propose Projection-based Point Convolution (PPConv), a point convolutional module that uses 2D convolutions and multi-layer perceptrons (MLPs) as its components. In PPConv, point features are processed through two branches: point branch and projection branch. Point branch consists of MLPs, while projection branch transforms point features into a 2D feature map and then apply 2D convolutions. As PPConv does not use point-based or voxel-based convolutions, it has advantages in fast point cloud processing. When combined with a learnable projection and effective feature fusion strategy, PPConv achieves superior efficiency compared to state-of-the-art methods, even with a simple architecture based on PointNet++. We demonstrate the efficiency of PPConv in terms of the trade-off between inference time and segmentation performance. The experimental results on S3DIS and ShapeNetPart show that PPConv is the most efficient method among the compared ones. The code is available at github.com/pahn04/PPConv.

A COMPARISON OF LASER AND STRUCTURED LIGHT SCANNING TECHNOLOGIES FOR ARCHAEOLOGICAL APPLICATIONS

Reverse engineering and in particular three-dimensional digitization have become an essential part of the documentation of archaeological findings. 3D scanning produces a high-precision digital reference document. The factors that influence the quality of the 3D scanned data are the scanned object’s surface colour, its glossiness and geometry, and the ambient light during the scanning process. However, the actual equipment and scanning technologies are of primary importance. The current paper presents a qualitative and quantitative comparison between two 3D scanning devices of different technologies; structured light 3D scanning and laser 3D scanning. The benchmark for this comparison is an ancient Roman vase from the city of Thessaloniki, Greece. The object was scanned with every possible setting on each scanner, but only one configuration of settings on each device was selected for the final comparison. The main criterion for the final selection of the two 3D models acquired with the use of the two technologies was the proximity in the number of points and polygons produced for digitally restoring the ancient vase in the best possible way. The results indicate important differences regarding the accuracy of the final digital model. The laser technology produced better accuracy but with a significant cost in scanning time and model data size. On the other hand, the structured light technology achieved the optimal combination of scanning quality and accuracy, along with reduced acquisition time of scan data.

DETERMINATION OF THE ACOUSTO-OPTICAL DEFLECTOR PARAMETERS FOR A LASER-RADIATION ROCKET GUIDANCE SYSTEM

The work is devoted to the development of an acousto-optic deflector for a laser-beam guidance system (LLSN) of missiles. LLSN is used in semiautomatic portable missile systems to destroy hostile targets of various types. An analysis of the methods for constructing such systems has shown that the most promising devices with pulse-code modulation using semiconductor pulsed lasers.&#x0D; The article provides a diagram and describes the principle of operation of the LLSN with pulse-code modulation. A problematic issue in the implementation of such a system is the development of a device for deflecting a laser beam, through which the missile is guided to a target. Scanning mechanical devices that are currently in use have a complex design, significant dimensions and weight, and limited performance.&#x0D; The article proposes to use an acousto-optic deflector to deflect the laser beam within the information field of the guidance system, which is devoid of these disadvantages, since it replaces the mechanical scanning device with an electronic one. The purpose of the article is to determine the main parameters of the acousto-optical deflector.&#x0D; The article discusses the principle of operation of an acousto-optic deflector. It is noted that glasses based on germanium chalcogenides, in particular, glass with the composition Ge2.17As39.13S58.70, have especially low values of acoustic losses (α &lt;1 dB / cm).&#x0D; The largest deflection angle of the laser beam will be observed with Bragg diffraction. Relationships are given that can be used to determine the main characteristics of the deflector: the angle of deflection of the laser beam, the modulation frequency of the acoustic wave, resolution, speed, and others. When using the above ratios for the typical parameters of the existing guidance system, the values of the indicated characteristics are calculated.