Photogrammetric Methods Research Articles

THE USE OF DRONES AND SENSORS IN AGRICULTURE

This paper presents the possibilities and benefits of using drones in agriculture, especially in precision agriculture. In the first part of the paper, basic notions regarding drones in the agricultural context, legislative and flight safety aspects are presented, defined and clarified. In the second part of the paper, the most used sensors in agriculture are introduced, the benefits and the main stages of using drones in agriculture are presented, related to the life span of a crop and the duration of the agricultural year. This paper encourages and justifies the use of drones both in current agricultural operations and by applying photogrammetric methods and generating digital products such as orthophoto plans, thematic maps and digital terrain models.

Photogrammetric and geodetic control of laying work

Photogrammetric methods in building control with the development of modern technologies prove their effectiveness in comparison with geodetic ones. The construction and inspection of buildings, structures, complex equipment can be provided at each stage with the results of aerial surveys and the construction of three-dimensional models on their basis for high-quality control of processes. In the control and executive surveys of structures under construction, photogrammetric methods are also used as an alternative or as an addition to traditional geodetic surveys. Such a replacement is especially effective in geodetic support for the construction of unique structures of complex architecture. The article describes a detailed overview of the control procedure, stages of work and formulas for calculations. The results obtained indicate good convergence of geodetic and photogrammetric executive surveys and high-quality performance of geodetic works. And the rapid development of instrumentation and the improvement of photogrammetric measuring systems using digital technologies and machine vision make it possible to increase the accuracy of determining the position of points in images up to 0.1 mm. The issues considered in the article expand the range of tasks to be solved in the field of construction control.

Changes in body posture parameters: a four-year follow-up study

Body posture is an alignment of its segments relative to each other in a certain way and the relations between them. Abnormalities in the alignment of body segments or the cooperation of systems may cause postural defects. Scientific evidence showed that children of school age are more exposed to abnormalities in body posture so posture should be monitored because it is a key aspect of their body's physical health. This study aimed to evaluate changes in body posture parameters in the frontal plane in the same children at 5 and then 9 years of age. This four-year follow-up study included 67 children (29 girls and 38 boys) in preschool-age and school-age phases (the first examination at 5 years of age and the second examination at 9 years of age). Measurements of body weight and height were recorded. The computerized assessment of body posture was performed with the photogrammetric method (MORA 4 Generation). The normality of the distribution of variables was assessed with the Shapiro-Wilk test. Analysis of qualitative data was carried out using Pearson’s chi-squared test. The highest percentage of children were characterized by the deterioration in the position of the lower corners of the scapulae, taking into account the division into sex (respectively in girls 51.7 % and boys 50.0 %) and the analysis of the whole group (50.7 %). There were statistically significant differences in the position of the lower corners of scapulae (UL) between the first and second examinations in all examined children (p = 0.005). The difference in the height of the waist and in the position of the shoulders improved and deteriorated in a similar percentage in children (above 30-40 %). Generally, an improvement in body posture was observed, however, the occurred abnormalities of body posture indicate the need to continuously monitor the children's posture and implementation of preventive and corrective measures.

The Comparison of Laser Diffraction, PDA and Photogrammetry for Aerosol Measurement

Optical methods are established as a standard tool for aerosol size measurement. The aim of this paper is to compare the results of two commercial optical instruments based on the phase-Doppler anemometry (PDA) and laser diffraction (LD) with the inhouse optical photogrammetric measurement method. For the purpose of this measurement, a new inhouse image processing procedure was developed with the use of MATLAB script. The accuracy of this method was tested on several calibration particle samples with a sufficient agreement with the PDA and LD commercial instruments. Subsequently, the water droplet distributions of a two-phase nozzle were evaluated by all three methods. The knowledge of the detailed droplet size distribution of the nozzle is then to be used for the development of a new facility for the study of heterogeneous droplet nucleation. Moreover, these results are useful for determining the advantages and disadvantages of these methods for their application in the wider field of aerosol technology.

Photogrammetrically UAV based terrain data generation and automatic extraction of torrential properties

Debris flows are a severe hazard in mountainous regions. However, cost-effective long-term studies of debris flows are seldom, which leads to substantial uncertainties in hazard mitigation methods. This paper investigates whether cost-effective remote sensing techniques can be applied to assess the hazards of mountain torrents and to gather accurate long-term information on the development of the watershed. Torrents that are prone to debris flows are often devoid of vegetation and can thus be well surveyed using photogrammetric methods based on uncrewed aerial vehicle (UAV) surveys. The possibility of extracting automatically torrent parameters from high-resolution terrain models, such as cross-sectional area or slope, is explored. The presented methodology yields continuous and automatically derived parameters along the torrent, which is a major advantage over pointwise field surveys. Cross-validation with field measurements reveals a strong agreement. These parameters are very accurate along highly incised sections, while they are severely limited along sections with steep adjacent hillslopes and/or dense vegetation. We show that these kinds of assessments greatly gain from UAV data followed by automatic parameter extraction. The extracted parameters provide insights so that key sections and weak points can be identified and accurately assessed in the field. We find that UAV data can contribute to a comprehensive, reproducible and objective assessment of torrent processes and predispositions. However, ground-based fieldwork is still essential and further research on remote sensing-based hazard assessment of torrents prone to debris flows is crucial.

Выявление следов антропогенной деятельности советского периода по данным аэрофотосъемки в дельтах рек Бугульдейки и Голоустной (Байкальский регион)

In 2021 and 2022 unmanned aerial photography of the deltas of the Goloustnaya and Buguldeyka Rivers, located on the northwestern shore of Lake Baikal, were performed. Using the photogrammetric method implemented in the “Agisoft Metashape” software, ultra-high-resolution orthomosaics and digital surface models (DSM) were built. When deciphering the obtained materials, technogenic surface changes that are not associated with land development in recent decades were found. The involvement of historical data made it possible to identify traces of anthropogenic activity in the river deltas belonging to the Soviet-era of the country’s development. In the Goloustnaya River delta, which is now almost uninhabited over a larger area, and represents a steppe with islands of relict poplars, the locations of the houses of the Zarechny and Podkamenny uluses, which existed from pre-revolutionary times until 1958, were revealed. The boundaries of these settlements and agricultural land belonging to their inhabitants and collective farms were reconstructed. In both deltas, traces of large-scale logging works, unique photographs of which are presented for the first time in this article, were preserved on the surface. Places of accumulation of sunken forests on the shores of Lake Baikal and in some channels of the Goloustnaya River were revealed. On practice, the obtained data can be used in historical reconstructions, for example, when creating models of the arrangement of deltas in the Soviet-era for regional museums in modern villages and visitor centers of the Pribaikalsky National Park. The results may also be useful in environmental surveys combined with timber extraction in order to clean the bottom of water bodies.

Estimating Ground Elevation in Coastal Dunes from High-Resolution UAV-LIDAR Point Clouds and Photogrammetry

Coastal dune environments play a critical role in protecting coastal areas from damage associated with flooding and excessive erosion. Therefore, monitoring the morphology of dunes is an important coastal management operation. Traditional ground-based survey methods are time-consuming, and data must be interpolated over large areas, thus limiting the ability to assess small-scale details. High-resolution uncrewed aerial vehicle (UAV) photogrammetry allows one to rapidly monitor coastal dune elevations at a fine scale and assess the vulnerability of coastal zones. However, photogrammetric methods are unable to map ground elevations beneath vegetation and only provide elevations for bare sand areas. This drawback is significant as vegetated areas play a key role in the development of dune morphology. To provide a complete digital terrain model for a coastal dune environment at Topsail Hill Preserve in Florida’s panhandle, we employed a UAV, equipped with a laser scanner and a high-resolution camera. Along with the UAV survey, we conducted a RTK–GNSS ground survey of 526 checkpoints within the survey area to serve as training/testing data for various machine-learning regression models to predict the ground elevation. Our results indicate that a UAV–LIDAR point cloud, coupled with a genetic algorithm provided the most accurate estimate for ground elevation (mean absolute error ± root mean square error, MAE ± RMSE = 7.64 ± 9.86 cm).

Water-Quality Monitoring with a UAV-Mounted Multispectral Camera in Coastal Waters

Remote-sensing ocean colour studies have already been used to determine coastal water quality, coastal biodiversity, and nutrient availability. In recent years, Unmanned Aerial Vehicles (UAVs) equipped with multispectral sensors, originally designed for agriculture applications, have also enabled water-quality studies of coastal waters. However, since the sea surface is constantly changing, commonly used photogrammetric methods fail when applied to UAV images captured over water areas. In this work, we evaluate the applicability of a five-band multispectral sensor mounted on a UAV to derive scientifically valuable water parameters such as chlorophyll-a (Chl-a) concentration and total suspended solids (TSS), including a new Python workflow for the manual generation of an orthomosaic in aquatic areas exclusively based on the sensor’s metadata. We show water-quality details in two different sites along the Maltese coastline on the centimetre-scale, improving the existing approximations that are available for the region through Sentinel-3 OLCI imagery at a much lower spatial resolution of 300 m. The Chl-a and TSS values derived for the studied regions were within the expected ranges and varied between 0 to 3 mg/m3 and 10 to 20 mg/m3, respectively. Spectral comparisons were also carried out along with some statistics calculations such as RMSE, MAE, or bias in order to validate the obtained results.

Use of Archival Aerial Photos and Images Acquired Using UAV to Reconstruct the Changes of Annual Load of the Suburban Landfill: Case Study of Promnik, Poland

The aim of this study is to evaluate the rate of the changes of the annual volume of the municipal waste deposited in the landfill in Promnik, Poland in the period 2003–2020, and to assess the applicability of archival aerial photos for this kind of survey. The landfill analyzed in this article is the main recipient of garbage from the city of Kielce, with a population of 200,000. That assessment is crucial for municipal waste management planning, bio-gases management, expected use time and reclamation of landfill area. Important issues to consider are how the new legal regulations, in effect from 2012, affected the amount of the municipal waste and the rate of landfill growth. Measurement of the volume changes was conducted using a photogrammetric method on the archival aerial photos from 2003 to 2015 and aerial photos acquired using an unmanned air vehicle in 2020. Reference material was digital elevation model (DEM) of this area, derived from aerial laser scanning performed in 2014. Chamber works on the images were conducted using PCI Orthoengine and Agisoft Metashape software. DEMs of the landfill area were generated, and the volume changes of the dump canopy have been determined between 2003, 2014, 2015 and 2020. Height changes were measured along cross-sections and in probe of 150 random points. A significant decrease in the annual load of the municipal waste after 2014 has been found, from over 70,000 m3 to 50,000 m3, which proves the effectiveness of the regulations introduced in 2012. Bio-gas productivity potential of the bio-active municipal waste layer was also assessed.

Does distance matter? Embodiment and perception of personalized avatars in relation to the self-observation distance in virtual reality

Virtual reality applications employing avatar embodiment typically use virtual mirrors to allow users to perceive their digital selves not only from a first-person but also from a holistic third-person perspective. However, due to distance-related biases such as the distance compression effect or a reduced relative rendering resolution, the self-observation distance (SOD) between the user and the virtual mirror might influence how users perceive their embodied avatar. Our article systematically investigates the effects of a short (1 m), middle (2.5 m), and far (4 m) SOD between users and mirror on the perception of their personalized and self-embodied avatars. The avatars were photorealistic reconstructed using state-of-the-art photogrammetric methods. Thirty participants repeatedly faced their real-time animated self-embodied avatars in each of the three SOD conditions, where they were repeatedly altered in their body weight, and participants rated the 1) sense of embodiment, 2) body weight perception, and 3) affective appraisal towards their avatar. We found that the different SODs are unlikely to influence any of our measures except for the perceived body weight estimation difficulty. Here, the participants perceived the difficulty significantly higher for the farthest SOD. We further found that the participants’ self-esteem significantly impacted their ability to modify their avatar’s body weight to their current body weight and that it positively correlated with the perceived attractiveness of the avatar. Additionally, the participants’ concerns about their body shape affected how eerie they perceived their avatars. The participants’ self-esteem and concerns about their body shape influenced the perceived body weight estimation difficulty. We conclude that the virtual mirror in embodiment scenarios can be freely placed and varied at a distance of one to four meters from the user without expecting major effects on the perception of the avatar.

The possibility of using close-range photogrammetry in the inventory of historic complex basements - case study

In the community, historical objects play the role of witness to past history. Due to that fact, it is necessary to preserve and reconstruct cultural heritage objects and sites for the future generation. Image-based photogrammetric methods have been widely applied for this purpose for many years. Nowadays, Terrestrial Laser Scanning (TLS; range-based method), due to its advantages such as speed of data acquisition, high accuracy and independence from light conditions, is increasingly used in the inventory of complex historic buildings. Despite this, the development of modern image processing methods, i.e. Structure-from-Motion (SfM) and Multi-View Stereo (MVS), has meant that close-range photogrammetric techniques are still competitive with TLS. The article aimed to present the possibility of using close-range photogrammetry to inventory historic complex basements. Laser scanning was performed as part of the measurements (with a Z+F 5006h scanner), and a series of close-range images were taken with a full-frame non-metric Canon 5D Mark II camera. Based on the combined SfM and MVS methods, a dense point cloud was generated, which in a subsequent data processing step served as the basis for generating 3D models and cross-sections. To assess the quality of the generated documentation, the TLS data were used as ground-truth data, and the shape and cross-section mapping quality was compared. It is evident from the investment presented that the use of close-range photogrammetry methods makes it possible to generate documentation that meets the requirements of architectural studies and similar shape accuracy for historic complex basements.

The comparison of photogrammetric and terrestrial laser scanning methods in the documentation of small cultural heritage object – case study

Nowadays, 3D models are commonly used to protect, manage and preserve cultural heritage objects and sites. Two methods are widely used: close-range photogrammetry and terrestrial laser scanning. Both those methods are burdened by the errors caused by the measurement system and physical properties of the object being under development. This investigation aimed to present the potential and limitations of using the photogrammetric and terrestrial laser scanning methods to document small cultural heritage objects. The object is a water pumping station building located in the Museum of King John III's Palace at Wilanów. It is situated near Lake Wilanowskie; hence the access to one wall was considerably limited. Data were acquired by the Terrestrial Laser Scanner Z+F 5006h and full-frame camera Canon 5D Mark II with the focal length - 17, 24, 28, 35 mm. The close-range images were processed in the Agisoft Metashape program, and the Structure-from-Motion with MultiView Stereo approach was utilised for the dense point cloud generation. The extended quality assessment analysis was conducted in the CloudCompare program, and the comparison between point clouds and cross-sections derived from the dataset was compared. The result of performed investigation shows that the point cloud generated from photos taken with a lens with a focal length 35 mm is characterised by the highest accuracy.

HIGH RESOLUTION SURFACE RECONSTRUCTION OF CULTURAL HERITAGE OBJECTS USING SHAPE FROM POLARIZATION METHOD

Abstract. Nowadays, three-dimensional reconstruction is used in various fields like computer vision, computer graphics, mixed reality and digital twin. The three- dimensional reconstruction of cultural heritage objects is one of the most important applications in this area which is usually accomplished by close range photogrammetry. The problem here is that the images are often noisy, and the dense image matching method has significant limitations to reconstruct the geometric details of cultural heritage objects in practice. Therefore, displaying high-level details in three-dimensional models, especially for cultural heritage objects, is a severe challenge in this field. In this paper, the shape from polarization method has been investigated, a passive method with no drawbacks of active methods. In this method, the resolution of the depth maps can be dramatically increased using the information obtained from the polarization light by rotating a linear polarizing filter in front of a digital camera. Through these polarized images, the surface details of the object can be reconstructed locally with high accuracy. The fusion of polarization and photogrammetric methods is an appropriate solution for achieving high resolution three-dimensional reconstruction. The surface reconstruction assessments have been performed visually and quantitatively. The evaluations showed that the proposed method could significantly reconstruct the surfaces' details in the three-dimensional model compared to the photogrammetric method with 10 times higher depth resolution.

A STATISTICAL ANALYSIS FOR THE ASSESSMENT OF CLOSE-RANGE PHOTOGRAMMETRY GEOMETRICAL FEATURES

Abstract. An examination of the traceability and dependability of the virtualisation properties is prompted by the widespread use of three-dimensional models. The challenge of obtaining accuracy indicators directly from the photogrammetric method when a reference model is missing is widely acknowledged. In this study, a robust method based on a statistical analysis of the uncertainty associated with Tie Points (TPs) is presented to provide a strict framework for the informed processing of photogrammetric survey data. In the phases of Structure estimation, Structure optimisation, and Dense Cloud generation, the key steps and variables affecting data processing are described. The workflow is then applied to a specific bronze museum finding smaller than 20 cm in size. All tie points that overcome the filtering phase are included in the procedure and for their coordinates the covariance matrix is examined. The error ellipsoid is calculated and the distribution of the lengths of the major semi-axes is analysed to calculate an appropriate tolerance interval which can be used as an indicator of the accuracy of the entire photogrammetric process. Indeed, using the tolerance intervals tool allows for the derivation of a representative indicator that can be compared with the outcomes of other photogrammetric processes while overcoming the ambiguity of statistical indicators that are not representative in the case of a non-normal distribution.

The generation of high-resolution orthoimages based on TLS data and close-range images – the case study

The development of high-resolution geometric documentation plays a fundamental role in the conservation works and managing cultural heritage objects. Nowadays, orthoimages are increasingly being used for these purposes, as it is a combination of geometric accuracy (derived, among other things, from terrestrial laser scanning data and/or photogrammetric methods) and visual quality (based on information from images). The objective of this article is present the methodology of orthoimages generation based on the integration of data acquired by the Z+F 5006h terrestrial laser scanner and the Canon EOS 5D Mark II digital camera. In this investigation, the methodology of high-resolution and high-quality orthoimages was presented. The modified version of the Structure-from-Motion processed the data, and MultiView Stereo approaches based on integrating TLS data with close-range images and extended data analysis. The primary objective of the performed works presented in this paper was to optimise the quality of the high-resolution orthoimages

Verification of the Wołek Castle Model with the Actual State Using Digital Photogrammetry and Conventional Survey Methods

This paper presents the results of a study to assess the feasibility of using the Structure from Motion photogrammetric method to estimate what parts of Wołek Castle have survived from the 15th century to the present day. The photogrammetric measurements were made with a Nikon D5200 camera, and 249 mock-up images were obtained. Planimetry and altitude coordinates of the castle ruins were obtained using RTN GNSS measurements and the polar method. The measurements were made in the 2000 coordinate system in zone 6, the heights were obtained in the Kronstadt system. Two spatial models were made. The first one in the field scale was made using the ground control points measured in the terrain. The second one was made using ground control points measured on the model in the local system. The control measures were analyzed, the model compared with the actual orthophotomap, and it was estimated what part of the castle was preserved in reality.

Evaluation of photogrammetric methods for fast identification of defects

Wydawnictwo SIGMA-NOT wydaje czasopisma fachowe informujące swoich czytelników o najnowszych osiągnięciach naukowych i nowoczesnych rozwiązaniach technicznych w Polsce i na świecie, popularyzuje problemy techniczne oraz poszerza wiedzę i kulturę techniczną.

Accuracy Verification of Surface Models of Architectural Objects from the iPad LiDAR in the Context of Photogrammetry Methods

The creation of accurate three-dimensional models has been radically simplified in recent years by developing photogrammetric methods. However, the photogrammetric procedure requires complex data processing and does not provide an immediate 3D model, so its use during field (in situ) surveys is infeasible. This paper presents the mapping of fragments of built structures at different scales (finest detail, garden sculpture, architectural interior, building facade) by using a LiDAR sensor from the Apple iPad Pro mobile device. The resulting iPad LiDAR and photogrammetric models were compared with reference models derived from laser scanning and point measurements. For small objects with complex geometries acquired by iPad LiDAR, up to 50% of points were unaligned with the reference models, which is much more than for photogrammetric models. This was primarily due to much less frequent sampling and, consequently, a sparser grid. This simplification of object surfaces is highly beneficial in the case of walls and building facades as it smooths out their surfaces. The application potential of the IPad LiDAR Pro is severely constrained by its range cap being 5 m, which greatly limits the size of objects that can be recorded, and excludes most buildings.

Research on the Use of Aerial Scanning and Gis in the Design of Sustainable Agricultural Production Extension Works in an Agritourist Farm in Romania

The use of scanning technologies and digital photogrammetry with the help of drones in the field of agritourism activities in Romania is a topic of novelty, because all the data necessary for the implementation or development of such research can be collected very quickly and with maximum efficiency. The classic methods are cumbersome and with a high consumption of inputs, and human and financial resources. The case study presents a practical method of applying this technology in the case of the agritourist farm REMMAR, from Vâlcea county, Romania, which wants to expand its agricultural production capacity with ecological products. Graphic support was obtained by scanning or digitizing existing maps in the physical/printed format and by acquiring data of interest in the digital format by photogrammetric methods and aerial field scanning of the studied area. The original elements of the topic are: how to obtain images by using photogrammetric methods; developing the methodology of the research and the actual development, from setting the basic objectives to obtaining and presenting the final results; elaboration of the methodology of the needs analysis and designing the specific data model; designing and the practical implementation of the geographic information system in terms of structure, methods, and means of software implementation. The successful implementation of the system was achieved only under the conditions of the existence of a data model specific to the field of action, and first realizing the conceptual foundation of the applicable data model, which would allow the registration, storage, extraction, processing, and effective analysis of the data of interest. From a theoretical and practical point of view, the research has a unique character in Romania, because it presents for the first time the development of a standard methodology for the design, expansion, and promotion of agritourism farms. The built geographic information system (GIS) is an effective tool for the management and control of the quality and efficiency of works specific to sustainable agricultural production.

Experimental Approach to Developing Equatorial Soil Loss Equation

This paper aims to develop a soil loss equation used within an equatorial climate (2,300 – 6,000 mm of annual rainfall) and hilly terrain based on measured data from the experiment concerning measured erosion outcomes, called Equatorial Soil Loss Equation (EQSLE). The equation under development should consider high equatorial rainfall intensities and challenging topographical conditions, thus introducing the new factors – Equatorial Rainfall Erosivity Factor (Reqt-factor) and Equatorial Slope Length Factor (Leqt-factor). The process included a photogrammetric method and image processing for raindrop size distribution and an experimental plot setup for a length differential study. The final equation has the form of A=Reqt⸱Leqt⸱S⸱K⸱C⸱P for soil erosion estimation in the equatorial region with the involvement slope and hilly terrain. The performance of the Reqt-factor and Leqt-factor are evaluated using the experimental data, and works of literature are carried out for the results. The formation of the two factors has addressed the challenges of high rainfall intensities and extreme terrain conditions faced by Peninsular Malaysia and East Malaysia. In future work, more case studies on the performance of soil loss rate prediction should be conducted to improve the overall performance of EQSLE as well as the respective factors.