Laser Scanning Method Research Articles

556. Comparative In Vitro Transduction Efficiency of AAV Vector Serotypes 1-9 in Different Cellular Models

Recombinant viral vectors can be useful tools for expressing transgenes in neuronal cells to study disease mechanisms and to test for therapeutic effect. Recombinant adeno-associated virus (AAV), generated from a nonpathogenic parvovirus, has become the most widely used vector in gene therapy applications in human. However, lack of suitable animal models that accurately reflect the human disease phenotype often stalls the development of treatment strategies. To overcome this problem, research is focused on generating induced pluripotent stem cells (iPSCs) from affected human subjects as in vitro models to explore the potential of gene augmentation therapy. An advantage of iPSCs is that these cells can be differentiated along a retinal cell lineage. In this study, we differentiated iPSCs into Neural Progenitor Cells (NPC) and compared the in vitro transduction efficiency of AAV serotypes 1-9. Differentiated NPCs were characterized by immunocytochemistry with the expression of NPCs specific markers (Sox2, Nestin, Pax6). Experiments were carried out using different AAVs serotypes containing the same transgene cassette: an enhanced green-fluorescent protein (eGFP) reporter gene driven by the cytomegalovirus immediate-early (CMV) promoter. At 24 to 48 hours post transduction, positive GFP expressing cells are examined by laser scanning in Typhoon. Relative GFP expression was evaluated by using the software ImageJ. In addition to the laser scanning method, flow cytometry was used to evaluate GFP expression in the cell population. Live cell imaging and flow cytometry evaluation revealed that AAV2 is the most efficient vector for in vitro transduction in NPC followed by AAV1, AAV3 and AAV6 while AAV4, AAV5, AAV7, AAV8 and AAV9 showed no transduction or extremely low transduction efficiency.

Laser Scanning and Data Integration for Three-Dimensional Digital Recording of Complex Historical Structures: The Case of Mevlana Museum

Terrestrial laser scanning method is widely used in three-dimensional (3-D) modeling projects. Nevertheless it usually requires measurement data from other sources for full measurement of the shapes. In this study a 3-D model of the historical Mevlana Museum (Mevlana Mausoleum) in Konya, Turkey was created using state-of-the art measurement techniques. The building was measured by terrestrial laser scanner (TLS). In addition, some shapes of the indoor area were measured by a time-of-flight camera. Thus, a 3-D model of the building was created by combining datasets of all measurements. The point cloud model was created with 2.3 cm and 2.4 cm accuracy for outdoor and indoor measurements, and then it was registered to a georeferenced system. In addition a 3-D virtual model was created by mapping the texture on a mesh derived from the point cloud.

Application of laser scanning technology in different branches and on different stages of the lifecycle of objects

At the present time settlement, land use and resources-use systems existing on most of the territory of Russia are still poorly estimated, they are poorly adapted to contemporary economic situation and the possibilities of their efficient use are not analyzed. The majority of archive and statistical information about the territories is out of date, because in had been collected and analyzed in the end of 1980s. Such information can’t be the basis for constructing a plan of prospective development. The article is dedicated to the currency and advantages of the use of innovative methods of laser scanning for solving the problems of spatial planning, design, reconstruction and construction. Some information on the world experience of using laser scanning is offered as an exemplification of flexibility and efficiency of their use in different branches of business activity. It is suggested to implement the methods of laser scanning for the tasks of the further creation of geographic information system on the territory of the Russian Federation containing current data information. The author also gives examples of the use and the advantages of laser scanning of Baikal-Amur Mainline and Trans-Siberian areas, laser scanning of the highway “High-speed network Moscow-Kazan”, highway M-4 Don.

도로의 파손 상태를 자동관리하기 위한 동영상 기반 실시간 포트홀 탐지 시스템

Potholes are caused by the presence of water in the underlying soil structure, which weakens the road pavement by expansion and contraction of water at freezing and thawing temperatures. Recently, automatic pothole detection systems have been studied, such as vibration-based methods and laser scanning methods. However, the vibration-based methods have low detection accuracy and limited detection area. Moreover, the costs for laser scanning-based methods are significantly high. Thus, in this paper, we propose a new pothole detection system using a commercial black-box camera. Normally, the computing power of a commercial black-box camera is limited. Thus, the pothole detection algorithm should be designed to work with the embedded computing environment of a black-box camera. The designed pothole detection algorithm has been tested by implementing in a black-box camera. The experimental results are analyzed with specific evaluation metrics, such as sensitivity and precision. Our studies confirm that the proposed pothole detection system can be utilized to gather pothole information in real-time.

Efekt termiczny impulsowego lasera erbowego stosowanego do zdejmowania zamków ortodontycznych

Background. Deboning of ceramic brackets using a Er:YAG laser has become an acceptable method to facilitate the removal of such type of brackets. Therefore, research has been conducted to establish safer and more effective techniques. The pulse duration is one of the most critical parameters with respect to thermal effect on the pulp vitality.Objectives. The goal of the current research is to evaluate the thermal effect of different Er:YAG laser pulse durations in order to establish safe and effective protocols of debonding ceramic brackets.Material and Methods. The sample consisted of 45 premolars extracted for orthodontic purposes. A ceramic bracket was bonded to each tooth. The sample was divided into three groups: 15 teeth for pulse duration of 50 μs, 15 teeth for pulse duration of 100 μs, and 15 teeth for pulse duration of 300 μs. All the ceramic brackets were exposed to the Er:YAG laser for 6 s by laser scanning method, with the same air and water conditions, as well as the same pulse energy and repetition rate. The tooth temperature was monitored during debonding the brackets by a thermal camera, and the ceramic bracket was debonded after 18 s. Then, the samples were examined under a microscope to evaluate the presence of the adhesive material.Results. The results showed the absence of a statistically significant difference between the pulse duration of 50, 100 and 300 μs in relation to the rise in temperature of the tooth. However, a statistically significant difference was found in relation to the presence of adhesive materials between pulse duration 50 μs and both 100 and 300 μs, with no statistically significant difference between 100 and 300 μs.Conclusion. Within the limits of this study, both Er: YAG pulse durations of 100 and 300 μs are preferred during ceramic brackets debonding using the laser scanning method.

Circumferential versus Hand-held Laser Scanner Method for the Evaluation of Lower Limb Volumes in Normal-weight and Obese Subjects

Circumferential measurement (CM) for lower limbs volume computation is a simple and accurate method; however, its reliability depends on the operator’s skills. Recent studies support the use of a new technique for an accurate and reliable measurement of body segments based on 3D laser scanner method (LS3D). The detection of the limb volume in obese patients can be tricky, due to the excess of masses that may hamper the identification of anatomical landmarks. In this study, we wanted to compare CM and LS3D in terms of circumferential measures and volumes of lower limbs in normal-weight and in obese subjects. We measured lower limb volumes in 21 female obese and in 11 female healthy subjects with both methods. Our data show statistically significant differences in terms of volume as detected by CM and LS3D. In the comparison between methods, the control group had showed a higher number of parameters statistically different in comparison with the obese. The reason is related to the shape of the limb: whereas in lean subjects the leg shape is anatomically defined, in obese subjects the presence of fat layers masks the anatomical landmarks with the leg shape closely resembling a cone figure. In this latter case, the Frustum formula seems to better approximate the volume. LS3D presents with the advantage of detecting gibbousness and uneven limb shapes, i.e. in patients lymphedema, which can be overlooked by the Frustum formula. Our data suggest that LS3D may represent a suitable tool for clinical applications, especially for pre-post evaluations.

三维激光扫描与传统量测对植株苗期形态监测方法比较

本文介绍了三维激光扫描技术的原理、系统组成及其对玉米植株三维形态扫描的过程、数据的处理和形态特征参数获取的方法，并与传统量测方法进行比较探讨两种新旧方法的优劣。使用人工测量方法和三维激光扫描方法分别对12株玉米植株的株高、叶基角、茎秆直径及横截面积进行测量比较，研究结果表明，三维激光扫描的测量结果与人工测量结果规律性一致，可以替代人工测量。对同一植株的重复测量进行稳定性分析，发现三维激光扫描方法的测量结果变异性小于人工测量结果，人为影响因素小。但是在时间效率上，三维激光扫描方法还有待进一步提高。三维激光扫描能无损监测植株的三维形态结构，拓展了植株形态测量方法，对植物数字化有重要意义。 This paper introduces the principle of 3D laser scanning technology, its components of the system, process in maize morphology measurement and data processing method. Besides, how to gain the morphological parameter is elaborated. And 3D laser scanning technology is compared with the traditional method to explore the pros and cons of both approaches. 12 maize plants’ heights, leaf angles, stem diameters and cross-sectional areas are measured with artificial methods and 3D laser scanning method. The results show that the 3D laser scanning measurement results are consistent with the artificial measurement results and the former can replace the latter. After repeated measurements on the same plant by stability analysis, it is found that the variability of 3D laser scanning method result is less than artificial measurement result. The artificial factors play a smaller role in the 3D laser scanning method. 3D laser scanning can nondestructive measure the plant morphology. But it takes more time and its methods need further improvement. 3D laser scanning method expands the method of measurement of plant morphology and has important significance in plant digital.

Resistance of cold-formed high strength steel circular and polygonal sections — Part 1: Experimental investigations

This paper presents results from experiments performed on cold-formed high strength steel circular and polygonal sections. The test specimens were conceived to provide necessary information for development of tubular towers for wind turbines. A total of 32 high strength steel specimens were tested under uniaxial compression. Various thicknesses, openings and geometric imperfections were studied. Sixteen specimens without opening and sixteen specimens with opening were tested under axial compression in order to investigate influences of opening on the resistances. Tensile tests of coupon specimens taken from flat part, circular part and corner part were used to investigate basic properties of high strength steel material S650 and to evaluate influence of corner on the material strength and ductility. Initial geometric imperfections of the specimens were determined by using a 3D laser scanning method. The coupon test results were used to calibrate the ductile damage material models for modelling of fracture. Results from the experiments are fully described in this paper.

The laser scanner is a reliable method to estimate the biomass of a Senegalese sole (Solea senegalensis) population in a tank

The measurement of total fish biomass is an essential practice in the aquaculture management. The method commonly used which involves removing a sub-sample of fish from a tank, weighing it and extrapolating the result to the whole tank, carries a large error, is intense labor and causes great stress. Here, we tested a laser scanning method to estimate the total fish biomass from the total fish volume of a sole population (Solea senegalensis) in a tank. The ratio FB/FLV of fish biomass (FB), weighing the 100% of soles, versus the fish layer volume (FLV) measured by the laser scanning, is calculated. Different fish size (small and large) and stocking densities (very low, low, medium and high) were tested. To test the method in the worst conditions, in very low stocking density, fish were 3.0g±1.1 (individual mean weight±SD); but in low, medium and high stocking density fish were 234.0g±84.6 (individual mean weight±SD). The fish layer volume included the fish biomass and the interstitial water present among them, which can be estimated from the ratio FB/FLV. In medium and high rearing densities with larger fish the ratio takes values very close to 1 (0.957±0.021 and 0.967±0.011) giving percentages of interstitial water lower than 5%. But in very low stocking density (0.4kg/m2) with smaller fish (3.0g±1.1), the ratio FB/FLV was much lower, giving a non-realistic percentage of interstitial water estimation. The low ratios obtained at very low stocking densities are due to the resolution of the image catching process, which is aggravated when working with small fish, since the error of a pixel from a digital image represents a larger percentage of error than with larger fish and higher stocking density. It should be noted that the coefficient of variation (CV) obtained was very low (in all cases lower than 7.2%) and decreased as the stocking density increased achieving the lowest value (1.1%) at high stocking density. The laser scanning has proven to be a useful tool to estimate the total fish layer volume of flatfish, and thus fish biomass, in an aquaculture tank with a usual grow-out stocking density for sole, reducing the labor involved and the stress commonly associated to manual sampling.

Development of kinematic 3D laser scanning system for indoor mapping and as-built BIM using constrained SLAM.

The growing interest and use of indoor mapping is driving a demand for improved data-acquisition facility, efficiency and productivity in the era of the Building Information Model (BIM). The conventional static laser scanning method suffers from some limitations on its operability in complex indoor environments, due to the presence of occlusions. Full scanning of indoor spaces without loss of information requires that surveyors change the scanner position many times, which incurs extra work for registration of each scanned point cloud. Alternatively, a kinematic 3D laser scanning system, proposed herein, uses line-feature-based Simultaneous Localization and Mapping (SLAM) technique for continuous mapping. Moreover, to reduce the uncertainty of line-feature extraction, we incorporated constrained adjustment based on an assumption made with respect to typical indoor environments: that the main structures are formed of parallel or orthogonal line features. The superiority of the proposed constrained adjustment is its reduction for uncertainties of the adjusted lines, leading to successful data association process. In the present study, kinematic scanning with and without constrained adjustment were comparatively evaluated in two test sites, and the results confirmed the effectiveness of the proposed system. The accuracy of the 3D mapping result was additionally evaluated by comparison with the reference points acquired by a total station: the Euclidean average distance error was 0.034 m for the seminar room and 0.043 m for the corridor, which satisfied the error tolerance for point cloud acquisition (0.051 m) according to the guidelines of the General Services Administration for BIM accuracy.

Experimental Study Structure Of Gas-Liquid Flow In Rectangular Minichannel By Optical Methods

In this paper, using method of two-beam laser scanning and high-speed video was identified patterns of distribution phases in the cross-section of the rectangular channel 0.72 × 1.50 mm with hydraulic diameter of the order to capillary constant. The structure of the gas-liquid flow was studied including flow regimes and statistical characteristics of the two-phase flow in regime with elongated bubbles, transition flow and annular flow regime.

THREE DIMENSIONAL MODELING OF ARCHAEOLOGICAL ARTIFACT USING PHOTOMODELER SCANNER

This article describes the work of archaeological artifact data recording using close range photogrammetry method. A calibrated stereo camera was used to take the stereo images of the artifacts. Photomodeler Scanner software was used to process the stereo images to produce a three-dimensional model of the artifact. For verification purposes, VIVID 910 laser scanner was used to generate three-dimensional model of the same artifact. The study found that close range photogrammetry method is easy to use, with fast data recording, fast data processing and it is a method which is cheaper than the laser scanning method.

The Problems and Solution Offers, Faced During The 3d Modeling Process of Sekiliyurt Underground Shelters With Terrestrial Laser Scanning Method

The aim of this research
 is, to find out the practicality of using terrestrial laser scanners in the
 area of 3D modeling of underground cities and underground shelters and to offer
 a suggestion for possible problems. Our research concluded that the terrestrial
 laser scanners are suitable for mapping and modeling the underground shelters
 and cities and terrestrial laser scanning is a useful technique to obtain
 sensitive and detailed results for hastily scanned objects. Generated maps and
 measurements can be used as a base for future restoration and recreation works
 of the scanned objects.
 

Non-destructive identification of pull-off adhesion between concrete layers

Abstract This paper presents a methodology for the non-destructive identification of the values of pull-off adhesion between concrete layers in floors on the basis of parameters determined using three non-destructive testing (NDT) methods and artificial neural networks (ANN). The methodology is based on the earlier research by the author. There are three stages in the methodology: stage 1 in which two parameters are determined on the concrete substrate layer surface using the non-destructive 3D laser scanning method and three parameters are determined on the added concrete surface using the acoustic impulse response and impact-echo methods, stage 2 in which an ANN is trained and tested, and stage 3 in which numerical analyses of the results are carried out and the values of pull-off adhesion f c, b are identified. It is shown that the methodology is practicable, as demonstrated by the provided example.

Growth of residual stress-free ZnO films on SiO2/Si substrate at room temperature for MEMS devices

ZnO thick Stress relaxed films were deposited by reactive magnetron sputtering on 2”-wafer of SiO2/Si at room temperature. The residual stress of ZnO films was measured by measuring the curvature of wafer using laser scanning method and found in the range of 0.18 x 109 to 11.28 x 109 dyne/cm2 with compressive in nature. Sputter pressure changes the deposition rates, which strongly affects the residual stress and surface morphologies of ZnO films. The crystalline wurtzite structure of ZnO films were confirmed by X-ray diffraction and a shift in (0002) diffraction peak of ZnO towards lower 2θ angle was observed with increasing the compressive stress in the films. The band gap of ZnO films shows a red shift from ∼3.275 eV to ∼3.23 eV as compressive stress is increased, unlike the stress for III-nitride materials. A relationship between stress and band gap of ZnO was derived and proposed. The stress-free growth of piezoelectric films is very important for functional devices applications.

Back Analysis of the 2014 San Leo Landslide Using Combined Terrestrial Laser Scanning and 3D Distinct Element Modelling

Landslides of the lateral spreading type, involving brittle geological units overlying ductile terrains, are a common occurrence in the sandstone and limestone plateaux of the northern Apennines of Italy. The edges of these plateaux are often the location of rapid landslide phenomena, such as rock slides, rock falls and topples. In this paper, we present a back analysis of a recent landslide (February 2014), involving the north-eastern sector of the San Leo rock slab (northern Apennines, Emilia-Romagna Region) which is a representative example of this type of phenomena. The aquifer hosted in the fractured slab, due to its relatively higher secondary permeability in comparison to the lower clayey units leads to the development of perennial and ephemeral springs at the contact between the two units. The related piping erosion phenomena, together with slope processes in the clay-shales have led to the progressive undermining of the slab, eventually predisposing large-scale landslides. Stability analyses were conducted coupling terrestrial laser scanning (TLS) and distinct element methods (DEMs). TLS point clouds were analysed to determine the pre- and post-failure geometry, the extension of the detachment area and the joint network characteristics. The block dimensions in the landslide deposit were mapped and used to infer the spacing of the discontinuities for insertion into the numerical model. Three-dimensional distinct element simulations were conducted, with and without undermining of the rock slab. The analyses allowed an assessment of the role of the undermining, together with the presence of an almost vertical joint set, striking sub-parallel to the cliff orientation, on the development of the slope instability processes. Based on the TLS and on the numerical simulation results, an interpretation of the landslide mechanism is proposed.

A Cost‐Effective Laser Scanning Method for Mapping Stream Channel Geometry and Roughness

AbstractThis brief pilot study implements a camera‐based laser scanning system that potentially offers a viable, cost‐effective alternative to traditional terrestrial laser scanning (TLS) and LiDAR equipment. We adapted a low‐cost laser ranging system (SICK LSM111) to acquire area scans of the channel and bed for a temporarily diverted stream. The 5 m × 2 m study area was scanned at a 4 mm point spacing which resulted in a point cloud density of 5,600 points/m2. A local maxima search algorithm was applied to the point cloud and a grain size distribution of the stream bed was extracted. The 84th and 90th percentiles of this distribution, which are commonly used to characterize channel roughness, were 90 mm and 109 mm, respectively. Our example shows the system can resolve both large‐scale geometry (e.g., bed slope and channel width) and small‐scale roughness elements (e.g., grain sizes between about 30 and 255 mm) in an exposed stream channel thereby providing a resolution adequate for the estimation of ecohydraulic roughness parameters such as Manning's n. While more work is necessary to refine our specific field‐deployable system's design, these initial results are promising in particular for those working on a limited or fixed budget. This opens up a realm of laser scanning applications and monitoring strategies for water resources that may not have been possible previously due to cost limitations associated with traditional TLS systems.

3D as-is building energy modeling and diagnostics: A review of the state-of-the-art

To achieve ambitious cuts in energy consumptions of the building sector, recent efforts have focused on devising methods that can provide accurate representation of the as-is conditions for existing buildings and in turn increase the quality and effectiveness of building retrofits. Today, 3D geometrical models produced by computer vision and laser scanning methods can be used as the basis of energy modeling purposes. Several methods are also introduced to facilitate the diagnostics and measurement of the thermal and other environmental conditions. To this end, this paper extensively reviews the state-of-the-art techniques that can semi-automatically or automatically create as-is geometrical and thermal models for building energy modeling and retrofit assessment purposes. It also provides an overview on the main algorithms used by these methods for representing spatio-thermal point clouds, automatically converting these point clouds into semantic Building Information Models (BIM) in gbXML format for as-is energy modeling purposes, and also contrasting them with expected energy performance models. The underlying formulations and methods for measuring actual thermal resistance of the building assemblies and mapping them into gbXML-based representations are also presented. The most recent works in the IT-driven building automation system (BAS) for energy conservation purposes are also reviewed. Finally, the technology gaps that need to be addressed in future research are identified and discussed.

Research on the Point Cloud Data Processing Method of 3D Terrestrial Laser Scanning in Existing Railway Track

Characterized with efficient, accurate and non-contact measurement, and the fast and three-dimensional visualization features, using 3D terrestrial laser scanning technology in track static detection has attracted widespread attention. Based on the structural characteristics of the railway line, use Geomagic software and Cyclone software in the pre-processing stage, remove the noise and redundancy, package the data after registration, get the initial line model finally. In the data extraction stage, combined with professional needs, respectively research the data extraction of track pitch and direction, and the bed section, from line, plane, and body. Which have provided a good research idea for using 3D terrestrial laser scanning technology in track static detection, acceptance, and some other aspects.

Possibilities Of Using Innovative Sources Of Information On Real Estate In The Spatial Data Collection Process

Abstract The register of land and buildings is an essential source of information on real estate. The use of cadastral data in land management is manifold, starting from spatial planning, through the calculation of taxes, the designation of real estate in land and mortgage registers, and finally, in real estate management. The accuracy of information from public records, i.e. the register of land and buildings, obtained by entities managing property has a direct impact on the correctness of the conducted processes of land management. Data necessary to determine the position of boundaries of cadastral parcels are taken from surveying documentation accepted into the national geodetic and cartographic resource database. If there is no such documentation, or the data contained therein are not reliable, information on the boundaries of cadastral parcels are obtained by means of field or photogrammetric surveys, preceded by the determination of the course of these boundaries. The present article analyzes the requirements of legislature regarding real estate data contained in the register of land and buildings. The possibility of capturing such information using an innovative method of laser scanning was also identified and tested. The object of the research was a fragment of the Old Town in Cracow, which had previously been covered by classical surveying. Based on the national geodetic control points and in relation to the National Spatial Reference System, with reference to GNSS, surveys of buildings arranged in a compact development were performed with a terrestrial laser scanner in order to compare the accuracy of determining real estate boundaries using these two methods. Possibilities of collecting data on the developed real properties that could be incorporated into the 3D cadastre in the future were identified and the quality of the obtained information was rated.