Agisoft Photoscan Research Articles

Photogrammetric Modelling of Street Conditions Using A Vehicle-mounted Non-metric Camera

Monitoring and modeling pavement distresses can employ either simple methods like direct measurements by tapes or straight edges, or more sophisticated approaches like laser scanners and stereoscopic cameras held at the ends of fixed poles. This study aims to detect pavement distress’s shape and position, such as cracks. For this purpose, overlapped images were collected for the distressed area to obtain complete coverage of the street conditions located in front of the College of Engineering /University of Duhok. Kurdistan Region, Iraq. A single non-metric camera attached to the side and the front of the vehicle is the approach employed as an image-collecting device. The camera shutter speed is selected to have a sequence of overlapped images to be processed, producing the pavement surface orthomosaic. The plane of the image in this study is inclined or obliquely relative to the pavement surface, so a gap is expected in the overlap area in the near range. To overcome this drawback and other problems, an indoor grid and tiles test was conducted to obtain the required parameters such as focal length, overlap percentage, camera shutter speed, and vehicle speed.   Ground control points (GCPs) and checkpoints for processing and accuracy checks were provided in each test and distributed evenly in the model area. The indoor parameter collecting tests revealed that the Root Mean Square Error (RMSE) for the (15) checkpoints was ±0.013m in X and ±0.016m in Y coordinates. Using a larger tilt angle and increasing camera height gave a root mean square error of ±0.009m in X and ±0.013m in Y, respectively. Image processing was conducted using Agisoft PhotoScan as it provided adequate accuracy and modeling tools in several previous papers

Horizontal and Vertical Geometric Accuracy of Agisoft Photoscan and Pix4D Mapper Softwares at Kebun Raya Universitas Mulawarman in Samarinda, East Kalimantan, Indonesia

The advent of unmanned aerial vehicles has improved aerial photography, which is now aided by computer software for data acquisition and processing. These developments allow for accurate aerial photographs of Kebun Raya Universitas Mulamarwan Samarinda (KRUS) for managerial purposes. This study aims to compare the accuracy of horizontal and vertical geometry with Agisoft Photoscan (AP) and Pix4D Mapper (PM) software. The materials consisted of 150 aerial photographs of KRUS with eight ground control points (GCP) and one internal control point (ICP). Data were obtained from nine flight paths with AP and PM software linked to GCP and ICP. These data were processed and compared to manual measurements using linear error (LE) 90 and circular error (CE) 90 criteria. The commission omission equation was used for the object accuracy test on orthophoto. The vertical geometry accuracy test was carried out using the criteria of root mean square error (RMSE) and LE90 values on the digital elevation model. In comparison, the horizontal geometry accuracy test was performed by using the obtained orthophoto based on RMSE and CE90 criteria. The result demonstrated that the horizontal geometry accuracy for AP was higher than PM, indicated by lower RMSE and CE90 values, which were 0.091 versus 0.148 and 0.139 versus 0.224 for AP and PM, respectively. The vertical geometry accuracy was similar, with lower RMSE and LE90 values of 0.169 versus 0.309 and LE90 0.279 versus 0.224 for AP and PM, respectively. Furthermore, AP is a potential tool for KRUS spatial mapping.

Combined use of Terrestrial Laser Scanning and UAV Photogrammetry in producing the LoD3 of 3D high building model

Both Unmanned Aerial Vehicles (UAVs) and Terrestrial Laser Scanners (TLS) are important techniques for surveying and mapping. UAV equipment is commonly used to collect 2D or 3D data acquisition. Meanwhile, TLS equipment is used for obtaining only 3D data acquisition. However, if both are integrated, they were able to produce more accurate data. Multi-sensor data fusion helps overcome the limitations of a single sensor and enables a complete 3D model for the structure and better object classification. This study focuses on studying the combination of UAV and TLS technologies to collect, process data, and create the complete point cloud between two point clouds of the high building in Ha Long city, Quang Ninh province to establish a 3D model at LoD 3 detail level, with high accuracy. FARO FOCUS3D X130 and DJI Phantom 4 RTK equipments were used to acquire the data in the field. The aerial and ground data were processed using FARO SCENE 2019 and Agisoft PhotoScan software, respectively. The data integration process is done by converting both point clouds into the same coordinate system and then by aligning the same points of both points clouds in Cloud Compare. The result of this study is a 3D model at LoD 3 detail level of the high building based on the point cloud accuracy in centimeter level. The combined use of UAV and TLS technologies has proven to be possible to create a highly accurate 3D model, at the 1:500 scale of urban areas according to current standards.

Possibility the use of UAV platform for building’s crack length measurement

This study uses Unmanned Aerial Vehicle (UAV) as a platform to inspect and monitor a building. It focuses on the inspection of defects in buildings, especially cracks. The aim of this study is to investigate cracks on a building by using UAV photogrammetry. The building was used as an object for this study because there are demands from the building maintenance team to assess cracks on the building in an effective way, where it can help to provide reliable crack information. The selected building for this study was an old apartment building with cracks, making it appropriate for this study. There were several steps and procedure used to capture the image of cracks on the building. From the image captured by using UAV, measurement of the cracks can be identified by using a software. There were also different approaches for the output. First is the 3D model of the building and second is the measurement of cracks. The 3D model of the building was created by using Agisoft Photoscan software for the purpose of getting the overview of building dimension. The measurement of cracks was processed by using PhotoModeler software. The accuracy achieved for this study was ±0.8cm. The result showed that UAV photogrammetry can help the current surveying work, especially on building maintenance. Besides, it can capture the crack’s images from certain altitude. The authors used UAV for smart building monitoring assessment, which was less considered in the past.

Terrestrial and Airborne Structure from Motion Photogrammetry Applied for Change Detection within a Sinkhole in Thuringia, Germany

Detection of geomorphological changes based on structure from motion (SfM) photogrammetry is highly dependent on the quality of the 3D reconstruction from high-quality images and the correspondingly derived point precision estimates. For long-term monitoring, it is interesting to know if the resulting 3D point clouds and derived detectable changes over the years are comparable, even though different sensors and data collection methods were applied. Analyzing this, we took images of a sinkhole terrestrially with a Nikon D3000 and aerially with a DJI drone camera in 2017, 2018, and 2019 and computed 3D point clouds and precision maps using Agisoft PhotoScan and the SfM_Georef software. Applying the “multiscale model to model cloud comparison using precision maps” plugin (M3C2-PM) in CloudCompare, we analyzed the differences between the point clouds arising from the different sensors and data collection methods per year. Additionally, we were interested if the patterns of detectable change over the years were comparable between the data collection methods. Overall, we found that the spatial pattern of detectable changes of the sinkhole walls were generally similar between the aerial and terrestrial surveys, which were performed using different sensors and camera locations. Although the terrestrial data collection was easier to perform, there were often challenges due to terrain and vegetation around the sinkhole to safely acquire adequate viewing angles to cover the entire sinkhole, which the aerial survey was able to overcome. The local levels of detection were also considerably lower for point clouds resulting from aerial surveys, likely due to the ability to obtain closer-range imagery within the sinkhole.

A new method for automatic and accurate coded target recognition in oblique images to improve augmented reality precision

AbstractTo have an accurate augmented reality (AR) in a ubiquitous geospatial information system (UBGIS), camera poses should be accurately estimated. Consumer‐grade sensors of mobile phones do not provide high accuracies. Using artificial markers and image‐based techniques could be a good solution for accurately estimating camera pose parameters. Automatic detection of these markers in very oblique images is challenging. This article aims to combine targets and mobile phone sensors to improve augmented reality precision in visualizing underground infrastructures. To achieve this goal, we propose a new method for automatically recognizing coded targets (CTs) and identifying their centers in oblique images. Then, we estimate the camera pose by computing exterior orientation parameters by combining sensors and CTs for the space restriction procedure. Finally, we visualize underground infrastructures using AR. Comparing the results with the well‐known photogrammetry software Agisoft PhotoScan show that the proposed method is robust, fast, and invariant under different transformations of scaling, rotation, and incidence angle variations. It is also more accurate than the Agisoft with sub‐pixel accuracy (about 0.692 ± 0.141 pixels). Comparing the results of the vision‐based method of calculating exterior orientation parameters with the sensor‐based method demonstrates the precision improvement in camera pose estimation and thus better AR visualization.

Performance comparison analysis of 3D reconstruction modeling software in construction site visualization and mapping

Unmanned aerial vehicle (UAV) technology has overcome the limitations of conventional construction management methods using advanced and automated visualization and 3D reconstruction modeling techniques. Although the mapping techniques and reconstruction modeling software can generate real-time and high-resolution descriptive textural, physical, and spatial data, they may fail to develop an accurate and complete 3D model of the construction site. To generate a quality 3D reconstruction model, the construction manager must optimize the trade-offs among three major software-selection factors: functionalities, technical capabilities, and the system hardware specifications. These factors directly affect the robust 3D reconstruction model of the construction site and objects. Accordingly, the purpose of this research was to apply nine well-established 3D reconstruction modeling software tools (DroneDeploy, COLMAP, 3DF+Zephyr, Autodesk Recap, LiMapper, PhotoModeler, 3D Survey, AgiSoft Photoscan, and Pix4D Mapper) and compare their performances and reliabilities in generating complete 3D models. The research was conducted in an eco-home building at the University of Technology, Malaysia. A series of regression analyses were conducted to compare the performances of the selected 3D reconstruction modeling software in alignment and registration, distance computing, geometric measurement, and plugin execution. Regression analysis determined that among the software programs, LiMapper had the strongest positive linear correlation with the ground truth model. Furthermore, the correlation analysis showed a statistically significant p-value for all software, except for 3D Survey. In addition, the research found that Autodesk Recap generated the most-robust and highest-quality dense point clouds. DroneDeploy can create an accurate point cloud and triangulation without using many points as required by COLMAP and LiMapper. It was concluded that most of the software is robustly, positively, and linearly correlated with the corresponding ground truth model. In the future, other factors involving software selection should be studied, such as vendor-related, user-related, and automation factors.

SIRTU PROCESSING AREA MAPPING USING UAV TECHNOLOGY, PT. CIPTA JAYA MULIA, JAYAWIJAYA REGENCY, PAPUA PROVINCE

PT. Cipta Jaya Mulia, as a company that has a mining business scope, seeks to increase its production activities. One strategy applied to plan additional areas of gravel processing locations is mapping using drone technology. Mapping using drones can shorten the time of mapping, where this mapping lasts for 80 minutes covering the area mapped by 5 ha with the altitude of flying drones 50 meters above ground level. Drones produce raster data in the form of photos (jpg files) of 1448 photos. The data is then processed using the Agisoft Photoscan software. The unified photos can then be reprocessed in other mapping software like ArcGIS, Global Mapper, and AutoCAD. The mapping results will be used to plan the addition of the gravel processing area of PT. Jaya Jaya Mulia.

Documentación y análisis de un cepo de ancla romano y sus elementos iconográficos y epigráficos sellados

This paper aims to present the documentation and analysis methodology carried out on a lead trap from the ancient period, which belongs to the collection of traps in the Museum of Cádiz (Andalusia, Spain). The anchor stock had some interesting characteristics for this research. On the one hand, from the point of view of conservation and restoration, due to the alterations it presented. On the other hand, from a historical and archaeological point of view, it showed signs of reliefs on its surface hidden under the alteration products. The removal of the different layers of alteration that covered the surface during conservation and restoration treatments revealed an unpublished iconographic and epigraphic programme, as well as possible marks of use and manufacture. The poor state of conservation of the original surface made it impossible to visualise the details as a whole, so we applied photogrammetric methods, and subsequently processed models using various GIS analysis and point cloud processing softwares.Two photogrammetric models (in Agisoft PhotoScan) were made to document the trap in general: one prior to the conservation and restoration process; and a second three-dimensional (3D) model once the surface had been cleaned. The purpose of the second model was to visualise the reliefs programme in general, as well as the different surface details. The first complete 3D model of the object was used to perform a virtual reconstruction of the anchor including the elements that did not preserve, using a 3D modelling program (Blender).Nine areas of the stock surface were selected for the analyses of the various iconographic and epigraphic features, which were documented and processed in Agisoft PhotoScan. The Digital Elevation Model (DEM) and point cloud models were then processed with different analyses tools in Geographic Information System (GIS) (such as QGIS) and point cloud processing software (CloudCompare). Our results document a piece of highly interesting information from its surface consisting of reliefs of four dolphins; at least four rectangular stamps: two of them with possible inscriptions, and an anthropomorphic figure. Thanks to the comparative data, we conclude that the four dolphins were made with the same stamp during the stock manufacturing process. Further, we were able to reconstruct the dolphin stamp, partially preserved in each of the reliefs, by unifying the 3D models, thus revealing the original set. This system of stamping by means of reusable dies is well known in other elements such as amphorae but has not been studied in the specific case of lead traps.In the case of the epigraphic elements, the 3D documentation methodology revealed numerous micro-surface details, not visible under conventional documentation techniques, which could help specialists to interpret these inscriptions. Although they have not been analysed in this research, its documentation has promoted the appreciation of surface details that could refer to the manufacturing processes (moulds and tools) or the traces of use, providing historical information on this object. At the same time, the virtual reconstruction of the anchor has aided the formation of hypotheses on the dimensions and original appearance of the anchor. The different tools used, such as raster analysis using shadow mapping and point cloud alignment, proved to be very effective. They have fulfilled the established objectives and have helped to establish a possible analysis methodology for future lead traps with decorative elements. These types of artefacts recovered from underwater sites are very common in museum collections. In many cases, their state of conservation and the difficulty in handling them due to their size and weight make it difficult to document surface details. In this case, the multidisciplinary work of conservation and 3D documentation allows for high-quality documentation that is easy to access and exchange between researchers. The combined use of photogrammetric techniques with virtual RTI provides a non-invasive method for the object, low cost and easy processing compared to other conventional methods.

3D modeling methods and architectural history of the mansion on Tverskaya 21: a noble estate, the Moscow English Club, a museum

The article presents architectural history of the building of the Moscow English Club, located in the center of Moscow on Tverskaya Street using the methods of three-dimensional modeling. The object of study is an object of cultural heritage, which during its history used to be a city estate, a noble club and now is a museum. Features of its location, historical events, socio-cultural context and change of purpose have influenced both the external design of the building and its internal structure. The author identifies and analyzes causes of changes in the architecture of the building, summarizes information from archival sources, identifies inaccuracies and contradictions that are found in documents. Based on materials from the funds of the Schusev State Museum of Architecture, the Central State Archive of Moscow and published sources, the author systematized the architectural history of the building and information about its owners. The data on the reconstruction of the building, based on the comparison of drawings and explanations to them, applications and projects, sketches and site plans, were shown in the scheme. For 3D visualization in 3Ds max six time periods were chosen: 1830s, 1875, 1883, 1896, 1912, 1940s. Agisoft PhotoScan and Adobe Photoshop were also used in the work.

Evaluation of two stereophotogrametry software for 3D reconstruction of virtual facial models.

ABSTRACTObjective: The present study aimed to evaluate the accuracy of 3D facial soft tissue virtual models produced by two photogrammetry softwares (AgiSoft Photoscan and 3DF Zephyr Free), when compared to those created by cone beam computed tomography (CBCT). Methods: Ten patients were submitted to two sequences of photographs performed with a DSLR camera (with and without the aid of a ring flash) and CBCT scans. Each photo series for each patient was processed with the softwares, and at the end, five models of each patient were generated: 1) CBCT, 2) AAL (Agisoft Ambient Light), 3) AFL (Agisoft Flash Light), 4) ZAL (Zephyr Ambient Light), and 5) ZFL (Zephyr Flash Light). Color coded maps and root-mean-square (RMS) distances were used to compare the photogrammetry models to the CBCT ones. Results: One sample t-test showed significant differences between all methods versus CBCT. The worst results were seen in the ZAL group (discrepancies up to 5.17mm), while the best results were produced by AAL group (discrepancies up to 2.11mm). Conclusions: It can be concluded that this type of virtual facial models are reasonably accurate, although not perfect, and considering its lower biological and financial cost, they may play an important role in specific situations.

Об опыте разработки ГИС-проекта кампуса университета

The article discusses the results of the work on the design and creation of a GIS project of the university campus. A model and methodology for creating a geographical information system (GIS) of the university campus was developed and tested in the Non-profit limited company “Manash Kozybayev North Kazakhstan university” setting. The GIS was created on the basis of open spatial data of the Remote Sensing of the Earth, materials of ground photography and aerial photography from an unmanned aerial vehicle (UAV). Geoinformation mapping and modeling was carried out using specialized programs: ArcGIS 10.4 (ESRI Inc.), Agisoft PhotoScan Professional Edition. The article presents the GIS structure of the campus, its main elements, and describes the stages of development. The work on the creation of GIS included the following stages: the development of its preliminary model and structure, the collection of the necessary initial information and data about the studied territory, the conduct of ground surveys and aerial photography, field work, processing of collected materials in special software applications, the creation of an electronic map and database, filling and correcting the latter. The campus GIS includes a digital cartographic framework and an associated database. Its structure contains a number of modules that combine thematic layers. Along with this, geo-referenced photorealistic three-dimensional models of university buildings were created during the research. A 3D model of the campus was built on the basis of aerial photography materials from the UAV. Developed GIS, its functionality can be useful to the university and find application in solving practical problems. The research was carried out within the framework of grant funding under the Sustainability Living Lab program.

The application of unmanned aircraft vehicle (UAV) to monitor construction area changes

Recently, unmanned aerial vehicles (UAV) have been applied to various fields: mapping, aerial surveying, mine monitoring, construction monitoring, etc. UAVs have many advantages, such as high flexibility, low cost, and time savings, for each survey. This article studies a monitoring construction site project using photogrammetry images collected with a UAV Phantom 4 Pro. The study area was the Viet Phu Garden residential area in Phong Phu Commune, Binh Chanh District, Ho Chi Minh City. Due to the development of computer vision, photogrammetry was used to build 3D models. The study applied the structure-from-motion method to create point clouds, digital surface models (DSMs), and orthomosaics. The author monitored the area for six months (3 times of data collection) with Phantom 4 Pro using Agisoft Photoscan software to process and create products. We measured 28 points to make ground control points and checkpoints. The author proceeded to build orthomosaic and DSM 3 times to analyze changes in the area. The resolutions of the orthomosaic and DSM are 5.5 cm/pixel and 11 cm/pixel, respectively. We used checkpoints to evaluate horizontal and vertical errors. The root-mean-square error was less than 10 cm, which demonstrated the potential of UAVs for monitoring construction. We also used the DoD method to calculate the difference in DSM between each epoch. Then, we combined the DoD method with Orthomosaic to monitor the urban growth of the area. The results are divided into 2 main groups of changes, including changes in linear and regional form. Assessing the regional changes, the author divided 18 points into four main groups: New house, Completed house, House under construction, and other. Urban growth mainly occurred in the west and center of the study area. The results demonstrated that the use of the Phantom 4 Pro is appropriate for monitoring construction changes. The author recommended improving the quality of the results by combining them with the cadastral map to make planning and management easy.

Mapping coral reef using photogrammetry technique: A preliminary study at Pulau Udar Besar, Sabah, Malaysia.

Mapping of coral reefs is useful for understanding, monitoring and tracking their development. However, studies on reef mapping in the Southeast Asian region are limited. The main objectives of this study were to 1) map the coral reefs using photogrammetry in order to create a 3D map of the reef, and 2) determine the coral growth forms and identify the corals to the lowest possible taxa from the images. Data collection was conducted on 19 and 24 January 2018. All images were captured by applying photogrammetry technique using a digital camera with waterproof housing. Image reconstruction process was performed in Agisoft Photoscan and Blender, using the structure-from-motion (SfM) algorithms to reconstruct the 2-Dimensional images into a 3D model. The reef map generated from Agisoft Photoscan is of medium quality. Coral growth forms were determined and identified to the lowest possible taxa through the images. From the images, free-living corals of the family Fungiidae were the most common coral observed in the study site. In conclusion, the output of this study shows that reef mapping is possible using a photogrammetry approach and images can be used to identify coral growth forms.

Building envelope anomaly characterization and simulation using drone time-lapse thermography

Defects in building envelopes deteriorate over time without being visible to the human eye, while significantly impacting energy performance due to unaccounted heat transfer. Defects can be characterized in the infrared (IR) spectrum. However, IR readings are typically recorded at singular points in time, when in several cases anomalies can only be revealed at specific times of the day, possibly in different seasons of the year. This paper presents a novel workflow for 3D envelope defect characterization and modeling using aerial time-lapse IR data collection using drones. A comprehensive envelope thermal profile is developed for a case study building employing the photogrammetry software Agisoft Photoscan, which generates temporal IR inspections of building skins using multiple thermography orthomosaics. Point-cloud data is then translated into a CAD model and thermal zones for whole Building Energy Modeling (BEM) using Honeybee as a frontend to EnergyPlus to showcase the potential of inclusion of detailed 4D data. Envelope contributions in this case study’s anomalies showed heat losses of 6447.6 kWh, and Energy Use Intensity (EUI) differences of ∼2 kWh/m2/year from the baseline. Why there is currently little translation of this work in BEM software is discussed, while identifying limitations and future research in the employment of time-lapse thermography using drones for more accurate building envelope inspection and modeling.

3D-modeling of an experimenal wound channel caused by a piercing-cutting object with bilateral blade grinding

The research deals with the possibility to use up-to-date methods of 3D-modeling for diagnostics of piercing-cutting objects causing injuries with bilateral blade grinding. A virtual element of the wound channel is shown to be printed on 3D-printer and given to investigating bodies in order to increase the effective and objective search of a traumatic instrument. 
 Aim of the work. To apply the method of photogrammetry with further 3D-modeling of the wound channel formed by a piercing-cutting object with bilateral blade grinding for further examination of its morphological peculiarities and receiving its linear size with high accuracy in the space of graphics editor «3DsMax».
 Materials and methods. Fifteen experimental wound channels were made by means of alginate impression mass with rubber-like effect «Hydrogum 5» (firm «Zhermack», Italy), which becomes hard rapidly, remains elastic after polymerization, allows impresses to be obtained with an extremely smooth surface, most accurately preserves and reproduces characteristics of an immersed blade of the knife examined. To make experimental injury a piercing-cutting object was used – a knife with bilateral grinding of the blade 6,16 cm long, 2,6 cm wide in the base of the blade, and the blade in its middle part 0,3 cm thick. These sizes of the piercing-cutting instrument were obtained by means of sliding calipers with the error ±0,03-0,15 cm. The wound channel obtained was divided into fragments with a pitch about 3,5 cm. Every fragment of the wound channel was contrasted with a dye using 1 % brilliant green alcohol solution.
 All the fragments of the wound channel were opened parallel to its length and were placed on a rotary table located in a light cube to provide adequate illumination and photos were taken. The digital camera SONY RX 10 II was used for shooting. The object of shooting was labeled with a number, a fragment of a plotting scale 1,0 cm long was placed on it to calibrate the scale and control the sizes of the object examined in computer programs. The photos obtained in JPEG format were loaded into the computer program «Agisoft Photoscan», and 3D-textured models of a wound channel fragment were created in it. The model obtained and the texture was exported in «OBJ» format. The next stage of the work was to transfer 3D-models obtained into the graphic space of «3DsMax» program, where the scale of the model was calibrated. After that the wound channel was reconstructed in the graphics editor by means of 3D models of the wound channel fragments.
 Results. To compare differences between classical and new methods of examination at first linear dimensions of injuries were measured by means of a ruler. The depth of the wound channel was obtained consisting of two fragments according to the method of measuring the wound channel depth in the dead body by means of joining of its separate parts due to immersion and passing the blade in the victim’s body (in the skin, subcutaneous tissue with muscles, in the wall of the cavity and inside of it, in the internal organ and other anatomical structures). The width and length of the wound channel on various levels of immersion were registered in the similar way, which is an important diagnostic component during forensic expertise in case of piercing-cutting injuries.
 The next stage in our research was to examine and get linear dimensions of injuries by means of up-to-date technologies using 3D-models with the help of the graphics editor «3DsMax». In this case the computer program enabled to get the above results with a higher accuracy to 0.001 cm.
 Conclusions. The results obtained are indicative of high information value of the three dimensional methods to identify a traumatic piercing-cutting object by means of a spatial reconstruction of the wound channel fragments, which provides high accuracy in solving applied tasks in modern forensic practice and criminal law science. The method with the use of the graphics editor «3ds max» allows retrospective diagnostics of the wound channel fragments to be obtained followed by further comparison with an expected traumatic object.

3-D modelling and visualization of large building using photogrammetric approach

The progress in modern technologies such as precise lightweight cameras mounted on unmanned aerial vehicles (UAV) and the more user-friendly software in the photogrammetric field, allows for 3-D model construction of any structure or shape. Software now achieves in sequence the processes of matching, generating tie points, block bundle adjustment, and generating digital elevation models.The aim of this study is to make a virtual 3-D model of the college of engineering /University of Duhok. Kurdistan Region, Iraq. The data input is vertical and oblique imagery acquired by UAV, ground control points distributed on the surrounded ground, facades, and roof. Ground control points were measured by the GPS RTK system in addition to the reflectorless total station instrument. The data is processed mainly using Agisoft PhotoScan software as well as the Global Mapper and the ReCap software. The output is a 3-D model, digital elevation model, and orthomosaic.Geometric and visual inspections were carried out. Some imperfections appeared on the sharp edges and parapets of the building. In the geometric accuracy of selected points on the building, the maximum standard deviation in the coordinates was ±4cm. The relative accuracy in distance measurements were in the range of 0.72% to 4.92 %

UAV technique to localize landslide susceptibility and mitigation proposal: A case of Rinchending Goenpa landslide in Bhutan

Natural hazards such as landslides impose very high risks to the community and infrastructures. To mitigate such risk, proper long-term engineering solutions are must. Several studies conducted in the past proposed countermeasures on many occasions. Despite such interventions, the Rinchending Goenpa area still suffers high vulnerability to landslide hazard which continues every monsoon. To assess landslide characteristics in detail, we performed landslide susceptibility mapping using the unmanned aerial vehicle (UAV) technique and conducted a site investigation. High-resolution digital elevation model (DEM) was generated with the site-specific aerial photographs and processed in Agisoft PhotoScan to developed thematic layers in geographical information system (GIS) software. We implemented a multi-influencing factor (MIF) for deriving the influence of landslide conditioning factors and developed a landslide susceptibility map (LSM) using the weighted overlay method (WOM). The landslide conditioning factors include slope, elevation, aspect, topographical wetness index (TWI), and normalized difference vegetation index (NDVI). According to LSM, the areal coverage of landslide susceptibility of study area reveals 2.41% in very low susceptibility, 37.14% in low susceptibility, with highest in moderate susceptibility zone of 49.55% followed by 10.60% in high susceptibility zone, and 0.30% in the very high susceptible zone. Based on the zonal distribution of LSM, and considering findings from several other site investigation such as geophysical survey, the performance of existing countermeasures, soil characteristics, and footprint of last landslide occurrences, we proposed mitigation measures under each zone to provide long-term solutions.

3D MODELING OF EXPERIMENTAL WOUND CANAL CAUSED BY STABCUTTING TOOL WITH ONE-SIDED SHARPENING OF THE BLADE

The aim – to carry out 3D modelling of the wound canal formed by a stab-cuttingtool with one-sided sharpening of the blade, using photogrammetry method for furtherinvestigation of its morphological peculiarities and obtaining linear dimensions withhigh accuracy in the space of the graphic editor "3ds Max".Material and methods. Fifteen experimental wound canals were reconstructedby means of an alginate imprinting mass with a rubber-like effect "Hydrogum 5"(Zhermack, Italy), which hardens quickly, remains elastic after polymerization, allowsto obtain imprints with an extremely smooth surface andmost accurately preserves andreproduces the properties of the immersed in it blade of the knife under study. Astabcutting tool - a knife with one-sided sharpening of the blade, blade length - 9.6 cm,width in the place of the greatest blade thickening - 2.6 cm, butt thickness - 0.24 cmwas used to mark experimental damage. Given dimensions of the stab- cutting toolwere obtained by means of sliding caliper with an error of ± 0.03-0.15 cm. The formedwound canal was divided into fragments with a step of about 3.5 cm. Each fragmentof the wound canal was contrasted with dye (1% alcohol solution of diamond green).These fragments of the wound canal were opened parallel to its length and placed on arotating table, which was located in a light cube to provide sufficient illumination andphotography was performed. A SONY RX 10 II digital camera was used for taking aphotograph. The index number and a fragment of a scale ruler 1.0 cm long were placedon the object for further calibration of the scale and control of the dimensions of theobject under study in computer programs. The photos obtained in JPEG format wereloaded to the computer program "Agisoft Photoscan", where 3D textured models of thewound canal fragment were created. The obtained model and texture were exportedin OBJ format. Then the obtained 3D models were moved to the graphic space of theprogram "3ds max" to calibrate the scale of the model and in the graphic editor thereconstruction of the wound canal was carried by means of 3D models of its fragments.Results. Measurements of the linear dimentions of damages were carried out at firstby a classical method (by means of a ruler). In addition to, that the depth of the woundcanal, which consists of three fragments, was obtained according to the method ofmeasuring the depth of the wound canal in the body of the corpse by putting togetherits seperate parts in accordance with immersion and permeability of the blade in thevictim's body (skin, subcutaneous muscle tissue, cavity wall and in it itself, the internalorgan and other anatomical formations). Similarly, the width of the wound canal andthe distance between the corners from the side of the butt, which illustrate the thicknessof the blade of the cutting edge and the length of its separate fragments, which in itsturn reproduce the parameters of the blade of an acute traumatic object, were fixed at different levels of immersion.The next stage of our work was to study and obtain the linear dimensions of 3Dmodels’damage by means of a graphic editor "3ds max". In this case, the mentionedcomputer program allowed to obtain the dimensions, described by us,already by anorder with higher accuracy (up to 0.001 cm).The results, obtained by us in the experiment, allow to assert about the high accuracyof measurements, carried out using a computer program for 3D modeling "3ds Max".When combining the obtained linear dimensions of the damage with increased accuracyand the possibility to conduct retrospective diagnosis of the most specific part of thewound canal, formed by the blade belly, the level of accuracy and visualization of thecarried out forensic medical examination is significantly increased.Conclusions. The results, obtained by photogrammetry and 3D modeling of the woundcanal, make it possible to assert the increased accuracy of investigations of individualmorphological characteristics of the lesions and allow to conduct retrospectiveidentification of fragments of the wound canal with the instrument of injury. In additionto that, forensic medical experts receive a modern objective tool for the selection andidentification of the used stab- cutting tool among those provided for examination byjudicial investigation organs. The introduction of the modern methods of 3D modelinginto forensic medical and medical-criminal practice allows to improve the accuracyand visualization of the carrying out examinations and brings them to a new higherlevel.

3D МОДЕЛЮВАННЯ ЕКСПЕРИМЕНТАЛЬНОГО РАНОВОГО КАНАЛУ, СПРИЧИНЕНОГО КОЛЮЧЕ-РІЖУЧИМ ЗАСОБОМ З ОДНОБІЧНОЮ ЗАТОЧКОЮ ЛЕЗА

The aim – to carry out 3D modelling of the wound canal formed by a stab-cuttingtool with one-sided sharpening of the blade, using photogrammetry method for furtherinvestigation of its morphological peculiarities and obtaining linear dimensions withhigh accuracy in the space of the graphic editor 3ds Max.Material and methods. Fifteen experimental wound canals were reconstructedby means of an alginate imprinting mass with a rubber-like effect Hydrogum 5(Zhermack, Italy), which hardens quickly, remains elastic after polymerization, allowsto obtain imprints with an extremely smooth surface andmost accurately preserves andreproduces the properties of the immersed in it blade of the knife under study. Astabcutting tool - a knife with one-sided sharpening of the blade, blade length - 9.6 cm,width in the place of the greatest blade thickening - 2.6 cm, butt thickness - 0.24 cmwas used to mark experimental damage. Given dimensions of the stab- cutting toolwere obtained by means of sliding caliper with an error of ± 0.03-0.15 cm. The formedwound canal was divided into fragments with a step of about 3.5 cm. Each fragmentof the wound canal was contrasted with dye (1% alcohol solution of diamond green).These fragments of the wound canal were opened parallel to its length and placed on arotating table, which was located in a light cube to provide sufficient illumination andphotography was performed. A SONY RX 10 II digital camera was used for taking aphotograph. The index number and a fragment of a scale ruler 1.0 cm long were placedon the object for further calibration of the scale and control of the dimensions of theobject under study in computer programs. The photos obtained in JPEG format wereloaded to the computer program Agisoft Photoscan, where 3D textured models of thewound canal fragment were created. The obtained model and texture were exportedin OBJ format. Then the obtained 3D models were moved to the graphic space of theprogram 3ds max to calibrate the scale of the model and in the graphic editor thereconstruction of the wound canal was carried by means of 3D models of its fragments.Results. Measurements of the linear dimentions of damages were carried out at firstby a classical method (by means of a ruler). In addition to, that the depth of the woundcanal, which consists of three fragments, was obtained according to the method ofmeasuring the depth of the wound canal in the body of the corpse by putting togetherits seperate parts in accordance with immersion and permeability of the blade in thevictim's body (skin, subcutaneous muscle tissue, cavity wall and in it itself, the internalorgan and other anatomical formations). Similarly, the width of the wound canal andthe distance between the corners from the side of the butt, which illustrate the thicknessof the blade of the cutting edge and the length of its separate fragments, which in itsturn reproduce the parameters of the blade of an acute traumatic object, were fixed at different levels of immersion.The next stage of our work was to study and obtain the linear dimensions of 3Dmodels’damage by means of a graphic editor 3ds max. In this case, the mentionedcomputer program allowed to obtain the dimensions, described by us,already by anorder with higher accuracy (up to 0.001 cm).The results, obtained by us in the experiment, allow to assert about the high accuracyof measurements, carried out using a computer program for 3D modeling 3ds Max.When combining the obtained linear dimensions of the damage with increased accuracyand the possibility to conduct retrospective diagnosis of the most specific part of thewound canal, formed by the blade belly, the level of accuracy and visualization of thecarried out forensic medical examination is significantly increased.Conclusions. The results, obtained by photogrammetry and 3D modeling of the woundcanal, make it possible to assert the increased accuracy of investigations of individualmorphological characteristics of the lesions and allow to conduct retrospectiveidentification of fragments of the wound canal with the instrument of injury. In additionto that, forensic medical experts receive a modern objective tool for the selection andidentification of the used stab- cutting tool among those provided for examination byjudicial investigation organs. The introduction of the modern methods of 3D modelinginto forensic medical and medical-criminal practice allows to improve the accuracyand visualization of the carrying out examinations and brings them to a new higherlevel.