Combining Laser Scanning Research Articles

THE INTEGRATED 3D SURVEY FOR UNDERGROUND ARCHAEOLOGICAL ENVIRONMENT

Abstract. The task of documentation and conservation of Cultural Heritage defines the challenges that geomatics techniques have to overtake in order to provide different solutions that combine the automation of processes with accurate results. The employment of integrated technologies allows improving the documentation of Cultural Heritage from a quantitative and qualitative point of view. The use of range and image-based techniques ensures the possibility to completely record articulated structures such as building with underground environments. The latter present often problematic survey conditions that imposed well planned and appropriate solutions. In this context, the paper presents the results of a 3D survey of the underground “Sybil hypogeum” and the related overhead church located in the Archaeological Park of Lilibeo (Marsala, Southern Italy). An integrated survey was planned in order to combine laser scanning technology with terrestrial-based and Unmanned Aerial Vehicle (UAV)-based photogrammetry to acquire the three-dimensional data of the whole complex (underground environments and overhead church). The aims of the work are related to test a topographic approach by a traverse method for scans registration and to archive a complete and detailed 3D model of the whole area. This model could be used to prevent the risk of information’s loss and to improve the knowledge of the site.

Archaeo-Geophysics Surveys in Pompeii

Within the extraordinary archaeological site of Pompeii, the Porta Nocera necropolis represents one of the most important sites with funerary monuments, burials and associated graves. The inherent informative potential of the archaeological/monumental heritage present in the Porta Nocera necropolis poses notable problems for the conservation and restoration of the structures and surfaces of the funerary monuments. Brought to light at different times during the second half of last century, they show signs of degradation caused by atmospheric agents and the rising level of the water table, which threatens the foundations. Other important monuments could be still buried. In order to verify both the state of preservation of the foundations of funerary buildings, the presence of still active causes of deterioration and the probable presence of other buried archaeological structures, integrated geophysical surveys, with ground penetrating radar (GPR), passive (Self Potential—SP) and active electrical resistivity tomography (ERT), were undertaken. Furthermore a three-dimensional model of the entire necropolis was created. This involved the creation of a specific survey methodology, combining laser scanning with ortho-photogrammetry using shots taken on the ground and from the air by the use of a drone. The integration of the acquired data allows us to plan future interventions of restoration.

BUILDING INFORMATION MODELS FOR MONITORING AND SIMULATION DATA IN HERITAGE BUILDINGS

Abstract. This paper analyses the use of BIM in heritage buildings, assessing the state-of-the-art and finding paths for further development. Specifically, this work is part of a broader project, which final aim is to support stakeholders through BIM. Given that humidity is one of the major causes of weathering, being able to detect, depict and forecast it, is a key task. A BIM model of a heritage building – enhanced with the integration of a weathering forecasting model – will be able to give detailed information on possible degradation patterns, and when they will happen. This information can be effectively used to plan both ordinary and extraordinary maintenance. The Jewel Tower in London, our case study, is digitised using combined laser scanning and photogrammetry, and a virtual model is produced. The point cloud derived from combined laser scanning & photogrammetry is traced out in with Autodesk Revit, where the main volumetry (gross walls and floors) is created with parametric objects. Surface characterisation of the façade is given through renderings. Specifically, new rendering materials have been created for this purpose, based on rectified photos of the Tower. The model is then integrated with moisture data, organised in spreadsheets and linked to it via parametric objects representing the points where measurements had been previously taken. The spatial distribution of moisture is then depicted using Dynamo. This simple exercise demonstrates the potential Dynamo has for condition reporting, and future work will concentrate on the creation of a complex forecasting model to be linked through it.

Position, orientation, and relative quantum yield ratio determination of fluorescent nanoemitters via combined laser scanning microscopy and polarization measurements

We present a universal method of determining the position, 3D orientation, and relative quantum yield ratio (RQYR) of fluorescent nanoemitters (ZnS coated CdSe quantum dots) in a glass slide by combining laser scanning microscopy (LSM) and polarization measurements. The quantum dots were located through LSM intensity maps using azimuthal, radial, and linear incident polarizations. LSM imaging was not sufficient to determine the orientation of the quantum dots due to the isotropic absorption dipole moment. The 3D orientation was obtained through polarization measurement. By combining LSM and polarization measurements, the RQYR of a single molecule was evaluated, allowing us to compare the quantum yield of the nanoemitters.

Opravdanost primene laserskog skeniranja pri verifikaciji zapremine rezervoara u odnosu na druge primenjene metode

A comparative analysis of the harmonic volume horizontal cylinder reservoir determined by electro-optical method, combined volume-geometric method, manual method and 3D laser scanning method was performed. The main goal is to verify the validity of the use of 3D laser scanners in the process of verification of the volume of horizontal cylinder reservoirs.

Ultrasonically synthesized organic liquid-filled chitosan microcapsules: part 2: characterization using AFM (atomic force microscopy) and combined AFM-confocal laser scanning fluorescence microscopy.

Atomic Force Microscopy (AFM) is used to measure the stiffness and Young's modulus of individual microcapsules that have a chitosan cross-linked shell encapsulating tetradecane. The oil filled microcapsules were prepared using a one pot synthesis via ultrasonic emulsification of tetradecane and crosslinking of the chitosan shell in aqueous solutions of acetic acid. The concentration of acetic acid in aqueous solutions of chitosan was varied from 0.2% to 25% v/v. The effect of acetic acid concentration and size of the individual microcapsules on the strength was probed. The deformations and forces required to rupture the microcapsules were also measured. Three dimensional deformations of microcapsules under large applied loads were obtained by the combination of Laser Scanning Confocal Microscopy (LSCM) with Atomic Force Microscopy (AFM). The stiffness, and hence the modulus, of the microcapsules was found to decrease with an increase in size with the average stiffness ranging from 82 to 111 mN m-1 and average Young's modulus ranging from 0.4 to 6.5 MPa. The forces required to rupture the microcapsules varied from 150 to 250 nN with deformations of the microcapsules up to 62 to 110% relative to their radius, respectively. Three dimensional images obtained using laser scanning confocal microscopy showed that the microcapsules retained their structure and shape after being subjected to large deformations and subsequent removal of the loads. Based on the above observations, the oil filled chitosan crosslinked microcapsules are an ideal choice for use in the food and pharmaceutical industries as they would be able to withstand the process conditions encountered.

Hybrid processing of laser scanning data

In this article the analysis of gaps in processing of raw laser scanning data and results of bridging the gaps discovered on the base of usage of laser scanning data for historic building information modeling is presented. The results of the development of a unified hybrid technology for the processing, storage, access and visualization of combined laser scanning and photography data about historical buildings are analyzed. The first result of the technology application for the historical building of St. Petersburg Polytechnic University shows reliability of the proposed approaches.

Extracting features from laser scanning point cloud

Analyses of gaps in processing of raw laser scanning data and results of bridging the gaps discovered on the basis of usage of laser scanning data for historic building information modelling are presented. Some results of the development of a unified hybrid technology for the processing, storage, access and visualization of combined laser scanning and photography data about historical buildings are analyzed. The first result of the technology application to historical building of St. Petersburg Polytechnic University shows the robustness of the approaches proposed.

Single-cell-based evaluation of sperm progressive motility via fluorescent assessment of mitochondria membrane potential

Sperm cells progressive motility is the most important parameter involved in the fertilization process. Sperm middle piece contains mitochondria, which play a critical role in energy production and whose proper operation ensures the reproductive success. Notably, sperm progressive motility is strictly related to mitochondrial membrane potential (MMP) and consequently to mitochondrial functionality. Although previous studies presented an evaluation of mitochondrial function through MMP assessment in entire sperm cells samples, a quantitative approach at single-cell level could provide more insights in the analysis of semen quality. Here we combine laser scanning confocal microscopy and functional fluorescent staining of mitochondrial membrane to assess MMP distribution among isolated spermatozoa. We found that the sperm fluorescence value increases as a function of growing progressive motility and that such fluorescence is influenced by MMP disruptors, potentially allowing for the discrimination of different quality classes of sperm cells in heterogeneous populations.

Mapping functional diversity from remotely sensed morphological and physiological forest traits

Assessing functional diversity from space can help predict productivity and stability of forest ecosystems at global scale using biodiversity–ecosystem functioning relationships. We present a new spatially continuous method to map regional patterns of tree functional diversity using combined laser scanning and imaging spectroscopy. The method does not require prior taxonomic information and integrates variation in plant functional traits between and within plant species. We compare our method with leaf-level field measurements and species-level plot inventory data and find reasonable agreement. Morphological and physiological diversity show consistent change with topography and soil, with low functional richness at a mountain ridge under specific environmental conditions. Overall, functional richness follows a logarithmic increase with area, whereas divergence and evenness are scale invariant. By mapping diversity at scales of individual trees to whole communities we demonstrate the potential of assessing functional diversity from space, providing a pathway only limited by technological advances and not by methodology.

Colloidal liquid crystals in square confinement: isotropic, nematic and smectic phases

We report on the confinement of colloidal liquid crystals in three dimensional chambers with a square footprint. To this end we use colloidal silica rods and exploit their relatively large density difference with respect to the dispersing solvent to study isotropic, nematic and smectic phases confined into a single chamber. Combining laser scanning confocal microscopy and soft-lithography techniques enables us to characterize the configurations down to the single particle level. We will focus on the smectic phase and compare to recent theories and simulations.

Cell adaptations of Rhodococcus rhodochrous IEGM 66 to betulin biotransformation

The findings of a comprehensive study on R. rhodochrous IEGM 66 and triterpenoid betulin interactions during its biotransformation were reported. In the presence of betulin, rhodococci were shown to form heterogeneous cell aggregates. The enhanced size of the aggregates from 12–15 μm to 25– 35 μm was consistent with the increase in betulin concentration from 0.5 to 3.0 g/L. The confocal laser scanning microscopy indicated a high (80.0%) level of rhodococcal viability during betulin biotransformation regardless of the betulin concentration. Experiments employing the combined confocal laser scanning and atomic force microscopy system confirmed that interactions between actinobacterial cells and betulin occur by direct contact. Transforming activities of the crude cell extracts from R. rhodochrous IEGM 66 were compared, and localization of enzymes catalyzing betulin oxidation to betulone was determined. Additionally the effects of betulin on fatty acid composition of rhodococci and their morphometric and morphofunctional characteristics during biotransformation were studied. Our findings could be used to develop approaches for enhanced betulin bioavailability, thus leading to improved biotransformation efficiency.

MULTISPECTRAL ANALYSIS OF INDIGENOUS ROCK ART USING TERRESTRIAL LASER SCANNING

Multispectral analysis is a widely used technique in the photogrammetric and remote sensing industry. The use of Terrestrial Laser Scanning (TLS) in combination with imagery is becoming increasingly common, with its applications spreading to a wider range of fields. Both systems benefit from being a non-contact technique that can be used to accurately capture data regarding the target surface. Although multispectral analysis is actively performed within the spatial sciences field, its extent of application within an archaeological context has been limited. This study effectively aims to apply the multispectral techniques commonly used, to a remote Indigenous site that contains an extensive gallery of aging rock art. The ultimate goal for this research is the development of a systematic procedure that could be applied to numerous similar sites for the purpose of heritage preservation and research. The study consisted of extensive data capture of the rock art gallery using two different TLS systems and a digital SLR camera. The data was combined into a common 2D reference frame that allowed for standard image processing to be applied. An unsupervised k-means classifier was applied to the multiband images to detect the different types of rock art present. The result was unsatisfactory as the subsequent classification accuracy was relatively low. The procedure and technique does however show potential and further testing with different classification algorithms could possibly improve the result significantly.

MULTISPECTRAL ANALYSIS OF INDIGENOUS ROCK ART USING TERRESTRIAL LASER SCANNING

Abstract. Multispectral analysis is a widely used technique in the photogrammetric and remote sensing industry. The use of Terrestrial Laser Scanning (TLS) in combination with imagery is becoming increasingly common, with its applications spreading to a wider range of fields. Both systems benefit from being a non-contact technique that can be used to accurately capture data regarding the target surface. Although multispectral analysis is actively performed within the spatial sciences field, its extent of application within an archaeological context has been limited. This study effectively aims to apply the multispectral techniques commonly used, to a remote Indigenous site that contains an extensive gallery of aging rock art. The ultimate goal for this research is the development of a systematic procedure that could be applied to numerous similar sites for the purpose of heritage preservation and research. The study consisted of extensive data capture of the rock art gallery using two different TLS systems and a digital SLR camera. The data was combined into a common 2D reference frame that allowed for standard image processing to be applied. An unsupervised k-means classifier was applied to the multiband images to detect the different types of rock art present. The result was unsatisfactory as the subsequent classification accuracy was relatively low. The procedure and technique does however show potential and further testing with different classification algorithms could possibly improve the result significantly.

(Re)presenting heritage: Laser scanning and 3D visualisations for cultural resilience and community engagement

Cultural heritage is increasingly being viewed as an economic asset for geographic areas who aim to capitalise in the surge in interest in local history and heritage tourism from members of the public. Digital technologies have developed that facilitate new forms of engagement with heritage and allow local areas to showcase their history, potentially broadening interest to a wider audience, thus acting as a driver for cultural and economic resilience. The research presented in this paper explores this through interdisciplinary research utilising laser scanning and visualisation in combination with social research in Elgin. 3D data capture technologies were used to develop and test 3D data visualisations and protocols through which the urban built heritage can be digitally recorded. The main focus of this paper surrounds the application and perceptions of these technologies. Findings suggest that the primary driver for cultural heritage developments was economic (with an emphasis on tourism) but further benefits and key factors of community engagement, social learning and cultural resilience were also reported. Stakeholder engagement and partnership working, in particular, were identified as critical factors of success. The findings from the community engagement events demonstrate that laser scanning and visualisation provide a novel and engaging mechanism for co-producing heritage assets. There is a high level of public interest in such technologies and users who engaged with these models reported that they gained new perspectives (including spatial and temporal perspectives) on the built heritage of the area.

Mapping Neuronal Connectivity using Laser Photostimulation and Calcium Imaging

Knowledge of the connectivity of a neuronal network is essential for understanding its activity and function. Current anatomical imaging techniques can be tedious and have a high degree of uncertainty. Electrophysiological techniques, although precise, are limited by network size. We present here a novel technique that allows relatively fast determination of connectivity in cultured neurons. This technique combines laser scanning photostimulation (via glutamate uncaging) to stimulate and calcium imaging to record activity of a large population of neurons. Mapping proceeds by selectively stimulating a single neuron and monitoring the response of nearby neurons to infer the postsynaptic connections. Within a few hours, we can generate a map of the functional connectivity of relatively large neuronal networks consisting of ∼150 neurons and ∼1500 connections. We describe the method in detail and discuss the feasibility of mapping neuronal microcircuits in acute brain slices.

The Impact of Field Data Capturing Technologies on Automated Construction Project Progress Monitoring

Accurate and timely information of construction project progress in a regular repeated basis is one of the critical stages of construction management. The purpose of this study is to investigate the impact of field data capturing technologies (FDCT), in combination with building information modelling (BIM) on automated construction project progress monitoring (ACPPM). The research is based on a survey of contracting and engineering consulting firms operating in the Middle East, Mid-Asia, Europe, North America, and Far East. Based on an evaluation of the findings, 3D Laser Scanning (LS), Image-based, and Radio Frequency Identification (RFID) technologies in combination with BIM were found as the most used technologies for ACPPM. At the end, a conceptual framework is illustrated and managerial implications are highlighted with a sample statement focusing on requirements, processes and benefits. The study confirms the importance of using BIM-based FDCT in enhancing ACPPM factors performance. It also highlights the need for further exploration of the role of the BIM-based FDCT in improving ACPPM.

The effect of organic solvents on the viability and morphofunctional properties of rhodococcus

The effect of organic solvents on the viability and structural-mechanical (size, surface roughness, and elasticity) properties of actinobacteria of the genus Rhodococcus was studied. The dependence of the survival of Rhodococcus on the hydrophobicity of the solvent, the culture density, and the incubation medium composition was demonstrated. The most resistant strains have been selected. Using combined confocal laser scanning and atomic force microscopy, we established that exposure to solvents resulted in an increase in the relative area and roughness of the surface of living cells and a decrease in their Young’s modulus. The involvement of protonand sodium-dependent efflux pumps in the formation of solvent tolerance in Rhodococcus was demonstrated.

Crop height variability detection in a single field by multi-temporal terrestrial laser scanning

Information on crop height, crop growth and biomass distribution is important for crop management and environmental modelling. For the determination of these parameters, terrestrial laser scanning in combination with real-time kinematic GPS (RTK–GPS) measurements was conducted in a multi-temporal approach in two consecutive years within a single field. Therefore, a time-of-flight laser scanner was mounted on a tripod. For georeferencing of the point clouds, all eight to nine positions of the laser scanner and several reflective targets were measured by RTK–GPS. The surveys were carried out three to four times during the growing periods of 2008 (sugar-beet) and 2009 (mainly winter barley). Crop surface models were established for every survey date with a horizontal resolution of 1 m, which can be used to derive maps of plant height and plant growth. The detected crop heights were consistent with observations from panoramic images and manual measurements (R2 = 0.53, RMSE = 0.1 m). Topographic and soil parameters were used for statistical analysis of the detected variability of crop height and significant correlations were found. Regression analysis (R2 < 0.31) emphasized the uncertainty of basic relations between the selected parameters and crop height variability within one field. Likewise, these patterns compared with the normalized difference vegetation index (NDVI) derived from satellite imagery show only minor significant correlations (r < 0.44).

3D imaging of cement-based materials at submicron resolution by combining laser scanning confocal microscopy with serial sectioning.

In this paper, we present a new method to reconstruct large volumes of nontransparent porous materials at submicron resolution. The proposed method combines fluorescence laser scanning confocal microscopy with serial sectioning to produce a series of overlapping confocal z-stacks, which are then aligned and stitched based on phase correlation. The method can be extended in the XY plane to further increase the overall image volume. Resolution of the reconstructed image volume does not degrade with increase in sample size. We have used the method to image cementitious materials, hardened cement paste and concrete and the results obtained show that the method is reliable. Possible applications of the method such as three-dimensional characterization of the pores and microcracks in hardened concrete, three-dimensional particle shape characterization of cementitious materials and three-dimensional characterization of other porous materials such as rocks and bioceramics are discussed.