Use Of Close Range Photogrammetry Research Articles

SURVEY OF HISTORICAL GARDENS: MULTI-CAMERA PHOTOGRAMMETRY VS MOBILE LASER SCANNING

Abstract. This paper presents an investigation into the characterization of historical gardens by comparing two 3D survey methodologies. In this context, approaches employing terrestrial laser scanning are considered the most accurate, while Mobile Mapping Systems (MMSs) are considered promising due to their extreme productivity. Less common is the use of close-range photogrammetry. This paper compares two approaches based on the use of a wearable MMS and the use of an in-house built photogrammetric multi-camera prototype. The comparison aims to assess the applicability of the two techniques in this field, evaluating their advantages and disadvantages in surveying a historical garden and extracting information for tree inventory, such as the DBH (Diameter at Breast Height) and canopy footprint. We compared the practicality of surveying and processing operations; and the quality and characteristics of the point clouds obtained. Both systems produced a dense representation of the terrain. The multi-camera survey resulted to be more defined due to the lower noise of the point cloud but incomplete in the definition of tree canopies. DBH of tree trunks can be extracted with both systems, except for thinner and finer diameter trunks detected by the MMS approach but not always by the multi-camera. The MMS approach proved more effective thanks to a shorter survey time required to cover an equal area and the fact that the MMS survey alone is sufficient for the geometric description of trees. In contrast, the multi-camera approach cannot avoid integration with an aerial survey for canopy reconstruction.

Inferred oviraptorosaur footprints in the Apenninic Carbonate Platform: New tools for the identification of trackmakers from the Sezze ichnosite (lower-middle Cenomanian; central Italy)

Herein we apply a new approach to the study of theropod footprints with elongated metatarsal traces from the Upper Cretaceous (lower-middle Cenomanian) Sezze ichnosite (Latium, central Italy). In this study, we combine traditional methods and new tools (i.e., close-range digital photogrammetry, sUAS – small Unmanned Aerial System, Principal Component Analysis, and Cluster Analysis) to identify the osteological features of the foot mirrored in the traces, analyse the differential depth of impressions and reconstruct the anatomical structure of the trackmaker foot. The use of close-range photogrammetry allows us to improve the ichnological interpretation and analysis, focusing on anatomical features such as phalangeal pads and claw traces. A dataset consisting of measurements of 66 foot skeletons of theropods and the five best preserved elongated footprints with metatarsal trace was subjected to Principal Component Analysis and Cluster Analysis, to investigate the morphospace occupied by the principal clade of theropods and find the most likely trackmaker among known taxa. The results indicate the clade of Oviraptorosauria as the more consistent producers for the Sezze theropod footprints, opening new questions about the clade dispersal and on the complex paleobiogeography of the Appenninic Carbonate Platform in the Late Cretaceous. The integrated multidisciplinary approach (high-resolution photogrammetry and morphometric analysis) confirms the utility of the new technological methodologies for the ichnological study.

Evaluation of Long-Range Mobile Mapping System (MMS) and Close-Range Photogrammetry for Deformation Monitoring. A Case Study of Cortes de Pallás in Valencia (Spain)

This contribution describes the methodology applied to evaluate the suitability of a Long-Range Mobile Mapping System to be integrated with other techniques that are currently used in a large and complex landslide deformation monitoring project carried out in Cortes de Pallás, in Valencia (Spain). Periodical geodetic surveys provide a reference frame realized by 10 pillars and 15 additional check points placed in specific points of interest, all with millimetric accuracy. The combined use of Close-Range Photogrammetry provides a well-controlled 3D model with 1–3 cm accuracy, making the area ideal for testing new technologies. Since some zones of interest are usually obstructed by construction, trees, or lamp posts, a possible solution might be the supplementary use of dynamic scanning instruments with the mobile mapping solution Kaarta Stencil 2 to collect the missing data. However, the reliability of this technology has to be assessed and validated before being integrated into the existing 3D models in the well-controlled area of Cortes de Pallás. The results of the experiment show that the accuracy achieved are compatible with those obtained from Close-Range Photogrammetry and can also be safely used to supplement image-based information for monitoring with 3–8 cm overall accuracy.

Use of close range photogrammetry in James Webb Space Telescope alignment testing under cryogenic conditions

The James Webb Space Telescope (JWST) cryogenic testing required measurement systems that both obtain a very high degree of accuracy and can function in that environment. Close-range photogrammetry was identified as meeting those criteria. Extensive modeling prior to installation verified that the design would meet the desired accuracy goals. Extensive validation work was done to ensure that the actual as-built system met accuracy and repeatability requirements. The simulated image data predicted the uncertainty in measurement to be within specification and this prediction was borne out experimentally. Uncertainty at all levels of a measurement volume that comprised 8 × 8 m was verified experimentally to be <0.1 mm with a repeatability of <0.03 mm at the primary mirror (PM) level, achieving measurement accuracies on par with a laser tracker or radar system. During a 3-month Optical Telescope Element and Integrated Science Instrument Module thermal vacuum test performed in chamber A at Johnson Space Center, the photogrammetric system provided key data to allow for verification of actuator ranges needed for on-orbit alignment of JWST, alignment of the PM and secondary mirror (SM), and positional information needed for thermal model verification.

Air void analysis of hardened concrete by means of photogrammetry

The present study investigates the use of close-range photogrammetry for automated air void analysis of hardened concrete without contrast enhancement.First, polished plane sections of concrete with varying air contents were analyzed by photogrammetry. The data in the form of point clouds were processed to identify the air voids. Second, the same plane sections were subjected to traditional air void analysis by contrast enhancement. Results of both methods were compared.The method based on photogrammetry showed potential, but it could not capture the smallest air voids. Better camera resolution and/or methods to reduce noise in the point cloud are needed.

Use of close-range photogrammetry and UAV in documentation of architecture monuments

The available photogrammetric solutions, combined with properly conducted surveying measurements enable to create fully applicable, three-dimensional models of architectural structures, which can be applied in, i.e. protection of cultural heritage or conservational documentation. Currently, we can see an increase in use of digital non-metric cameras in a photogrammetric inventory of sacred monuments. Properly obtained and analysed data allow to create a digital model of an object, which later might serve as a basis for a vector image used for architectural and construction purposes. The paper presents the procedure of creation of 3D models of sacred historic monuments of relatively small sizes with the use of terrestrial photogrammetry and UAV using the Agisoft PhotoScan Professional software.

The use of close-range photogrammetry in zooarchaeology: Creating accurate 3D models of wolf crania to study dog domestication

Close-range photographic techniques - including photogrammetry - are becoming common tools for constructing three-dimensional (3D) models of artifacts, particularly in archaeological research. Whether models obtained through photogrammetry can be used for zooarchaeological studies requires a systematic examination. In the context of research into dog domestication, we explore whether 3D models of wolf crania, obtained through a photogrammetric approach, accurately describe the original cranium in term of colouration, texture and most importantly, geometry.To answer this question, we compared the topology of 3D models obtained with a high-resolution surface scanner (used as reference geometry) with models reconstructed from the same five wolf crania using photogrammetry. The pairs of models were then compared using both a visual, qualitative and two quantitative approaches. The latter, a geometric comparison computed the deviation map between the pairs of 3D models, which was then followed by a 3D landmark based geometric morphometric approach using corresponding analyses.Our results demonstrate that photogrammetry can produce 3D models with visually satisfying levels of morphological detail in terms of texture, colouration and geometry. In addition, the quantitative comparison of the models revealed an average distance between the two surfaces of 0.088mm with an average standard deviation of 0.53mm. The geometric morphometric analyses revealed the same degree of measurement error for the two series of scans (2.04% and 1.95%), with only 6.31% of the morphometric variation being due to the acquisition technique. Photogrammetry, therefore, offers a low cost, easily portable and simple to perform alternative to traditional surface scanning, affording advantages that make it a highly useful tool for zooarchaeological research.

Close Range Photogrammetry and Constructive Characterization of Masonry Gothic Vaults

The representation of the plan of the roof in heritage buildings often raises the problem of direct measurement, since the points are not accessible. We currently have a wide range of indirect measurement techniques that solve this problem, and enable data to be captured on a massive scale with high levels of accuracy. The article discusses the use of Close Range Photogrammetry for the constructive analysis of gothic vaults in Tortosa Cathedral. The methodology and results of the campaign are explained below, which used technological resources that are available to any professional. The computerized processing of the 3D model generated makes possible to identify and analyze the geometric anomalies in the masonry vaults. Thereby it is obtained an unparalleled basis that enables us to undertake a detailed study of the vaulting, which was previously impossible. The geometrical deviation patterns can be related with the historical data available about the construction process of the gothic apse, fulfilling the lack of information from direct sources of some periods.

Displacement measurement of the soil nail walls by using close range photogrammetry and introduction of CPDA method

Displacement measurement of the soil nail walls is a very important task in monitoring tiny movements in excavations to prevent disastrous accidents like wall collapsing. In building construction projects, this is usually done by either micro-geodesy or accurate instrumentation methods. In this research, for the first time, the use of close range photogrammetry in displacement measurement of the soil nail walls has been proposed and experienced. For this, a photogrammetric system was designed, implemented and evaluated. Proposed system with three separate methods for displacement measurement, which one of them was submitted for the first time (CPDA), was implemented. The evaluation results the accuracy of 3mm is achievable in determining the point coordinates with a precision of 8mm in displacement measurement of soil nail walls. Due to the efficiency, low cost, high accuracy, high speed of observations along with the simplicity of implementation of close range photogrammetry, it is suggested as a proper alternative to the traditional methods.

Displacement Measurement of Soil Nail Walls using Close Range Photogrammetry

Abstract Displacement measurement of the soil nail walls is very important in monitoring the slightest movements in excavations to prevent disastrous accidents like wall collapsing. Usually in building construction projects, the micro-geodesy and instrumentation methods are used in measurement of vertical and horizontal movements of the walls. Limitations like high cost, long time, limited accuracy, low flexibility and high dependence on the project conditions are the causes of the low control on the movements of walls in many projects. Unfortunately in some cases adverse accidents occurs because of this reason. In this research, for the first time, the use of close range photogrammetry in displacement measurement of the soil nail walls has been proposed and experienced. For this purpose, a photogrammetric system has been designed and examined on a building construction project in Tehran, Iran. The results of monitoring of one the suspicious walls in the project in different time epochs of the excavation and its comparison with the consequences of the micro-geodesy method confirmed the accuracy of the proposed method (7.7 mm). According to this fact that the proposed method has solved the many limitations of the traditional methods, the close range photogrammetry as an efficient method is introduced as an alternative to the existing method in construction projects.

STUDYING GLACIAL MELT PROCESSES USING SUB-CENTIMETER DEM EXTRACTION AND DIGITAL CLOSE-RANGE PHOTOGRAMMETRY

Abstract. Glaciers are sensitive to climatic variation and a particular developing area of investigation is in the field of "cryoconite”, referring to dustlike residues which form on the glacier surface. Cryoconite absorbs the Sun's shortwave energy, accelerates ice melt and because of the localised distribution of dust creates localised melting which is highly spatially variable. There is therefore a need to quantify the detailed topographic surface of ice and measure its variability through time. This paper describes the use of close range photogrammetry to reconstruct the glacier surface at the sub-centimetre or micro scale, an approach which may allow the relationship between cryoconite and ice surface properties to be explored over either space or time. The field campaign was conducted at Midtre Lovénbreen, Svalbard (78.88° North 12.08° East), during the summer of 2010 and executed using simple equipment and procedures. A simple and ageing Nikon 5400 5 MP camera was used to acquire all imagery, proving sufficiently robust for the challenging field environment. The camera was handheld approximately 1.6 m above the ice surface, providing an oblique perspective. Images were acquired at three different camera/object distances, each generating coverage occupying three different areas. All imagery was processed using the commercial photogrammetric package PhotoModeler Scanner, generating threedimensional point clouds consisting of many thousands of XYZ coordinates, each colour-coded. It had been feared that lack of texture in the ice surface combined with differing specular reflections in each image would compromise the DEM generation process. Results were better than expected, although DEM quality proved to be variable depending on ice cleanliness and more significantly, the degree of obliquity of the image pairs. Despite these differences, digital close-range photogrammetry has proven to be a useful technique to reconstruct the glacier's surface to sub-centimeter precision. Moreover, the method is providing glacial scientists with new data to examine the relationship between cryoconite, ice surface roughness and melt processes.

Using digital close-range photogrammetry as a QA/QC tool in construction: practical cases

In the construction field, the terms quality assurance and quality control (QA/QC) have an important purpose, which is to provide the final product with the required quality. Some tools must be applied to ensure and control the quality of construction testing and measuring are important examples of such tools. Sometimes they require accurate measurements depending on the issue at hand. Close-range photogrammetry is one of the most important and accurate measuring techniques that does not require direct contact with an object. Additionally, most of the procedure for close-range photogrammetry can be carried out in the office. The objective of this paper is to present the use of close-range photogrammetry as a useful and accurate measuring tool for QA/QC in the construction field. We have applied close-range photogrammetry to two practical cases in a construction site to demonstrate its application to the issues of quality assurance and quality control.

Use of close-range photogrammetry to characterize fracture surfaces

Abstract Natural fractures are characterized by rough surfaces and complex fluid flows. A large distribution of apertures (residual voids) within their walls and the presence of contact points produce heterogeneous flows (channelling). The resulting permeabilities, porosities or fluid-rock exchange surfaces cannot be realistically modelled by parallel and smooth plate models. It is therefore very important to better constrain models of the fracture planes : asperity heights and aperture distribution to be able to fix specific models of permeability in specific fracture void geometry. In this approach, a precise description of the fracture surface planes is given by providing some new quantitative data of surface roughness in the case of natural fractures. Studied fractures are sampled in a granite and a sandstone in the deep basement of the Hot Dry Rock site of Soultzsous-Forêts (Bas-Rhin, France). An original use of close-range photogrammetry is performed to quantify XYZ data on fracture walls. This methodology is presented as a non destructive, precise and accurate technology to quantify some digital terrain models (DTM) of the fracture plane topography. XYZ results are statistically treated in terms of surface roughness and tortuosity and are compared for different rocks to previous data obtained by mechanical profilometry. The results shows that the photogrammetric approach gives same order of asperity heights magnitudes as profilometry despite a shift towards more important values of roughness when close range photogrammetry uses relative autocorrelation models. The advantage of photogrammetry is that this technique gives very quick results and is non destructive when thin alteration or pulverulent deposits are present within fracture walls or in the rock matrix. The disadvantage is that a slight smoothing of data is inherent to an absolute model calibration. Finally only relative 300*300 DTM are finally chosen to match profilometry data because of their higher precision in terms of micro roughness description to compare natural fracture surfaces. In the objective of a classification of fracture roughness in specific geological contexts, the photogrammetric approach gives a good estimation of different classes of roughness in function of rock alteration and type.

The Use of Close Range Photogrammetry for Studying Ice Accretion on Aerofoil Sections

This paper describes the use of photogrammetry to measure and quantify ice accretion on an aerofoil section. A series of stereoscopic photographs was taken during the ice accretion on the section in an icing tunnel. From measurements made on these photographs with a Kern (Leica) DSR 14 analytical photogrammetric plotter, a series of three dimensional models of the ice surfaces was constructed. The results of the project are discussed and possible improvements in the methodology are suggested.