Papers by Keyword: Photogrammetry

Abstract: Reconstructing a three-dimensional model of a real-world object requires a quality point cloud to produce an accurate three-dimensional model. Point clouds can be produced by image-based and distance-based methods. The image-based method utilises the light reflected by the object, which is then processed using the principle of photogrammetry. This research is intended to test the image-based method with the help of the structure from motion approach to generate the quality of point clouds using open-source software including Visual SfM, MicMac, Meshroom and with the Agisoft Metashape Pro commercial software. The images are taken by a Xiaomi Yi Action camera with 2.68 mm focal length. The performance comparisons will consider Volume Density, Surface Variation and Point discrepancy. We utilize BLK 360 terrestrial laser scanner to collect reference point cloud. The results show that all software provide convincing result on each parameters compared.

Abstract: This study introduces a novel methodology to determine the effective area of artificial tree camouflaged telecommunication towers, focusing on the pine tree type, using drone technology and photogrammetry. Accurate frontal area determination is essential for wind load calculations, critical to the structural design of such towers. Conducted on a telecommunication tower in East London, South Africa, the research applied image thresholding to point clouds generated from drone-captured images. The drone-derived frontal area of 23.484 m², when combined with a force coefficient of 0.5 from previous wind tunnel research, resulted in an effective area of 11.742 m², differing by less than 4% from the in-situ strain-derived effective area of 12.10 m² utilized as verification. The study addresses the lack of guidelines for designing camouflaged towers and highlights the advantages of drone technology over traditional methods. The results suggest a 47% reduction in the original design's effective area, leading to a 20% reduction in bending moments at the telecommunication tower base. This can result in cost savings by reducing the required structural capacity in future designs or increasing antenna space, which is crucial for 5G deployment. The research offers a practical solution to optimize existing telecommunication towers' capacity, improving efficiency without requiring new infrastructure.

Abstract: A low-cost method based on macro-photogrammetric reconstruction is presented to automatically detect wear and other defects in small gears created with additive manufacturing. This novel approach is oriented to preventive and predictive maintenance of gears in order to avoid faults in machines and devices. The experimentation has been conducted using three defective gears produced in Nylon PA-12. First, a robotic platform and a systematic macro-photogrammetric data acquisition procedure were used to accomplish the 3D reconstruction and generate the dense point clouds. Subsequently, a comparison between the dense point cloud and the ideal solid CAD model of the normalized gear has been carried out. For this aim, the models have been alignment in the same spatial system. The computation of the distances between solid models and point clouds allows the automatic visualization of different types of defects even for defects that are not visible to the naked eye. This conclusion has been checked from a statistical point of view considering the discrepancies obtained in the comparison and their distribution.

Abstract: We can find cultural monuments everywhere. Smaller ones are often made from available and cheap natural materials - stones. However, due to the weather, due to their smaller dimensions, are often subject to vandalism, damage caused by careless handling or accidental damage. Sometimes they are just pieces of stone, but they have a deeper meaning in connection with cultural value, and for example by studying them in office spaces in the form of 3D models. In our contribution, we focus on the protection, study and preservation of such cultural and artistic monuments made of natural materials or generally stone natural formations or even large stone or brick surfaces. In our article, we want to focus on the practical feasibility rather than the mathematical background, as we believe that this information is much more useful in practice. We point out that it is advisable to use drones to check the condition of materials.

Abstract: Technological advances in the digital camera industry and computing resources make the use of photogrammetry a very fast, low-cost, contactless and non-destructive technique. It can represent a good alternative to obtain 3D information for monitoring and conservation of cultural heritage assets, especially where it is not possible to use 3D laser scanners and also in situations where areas to be inspected are not easily accessible [1]. Resolution generally depends on the number of images, their quality and the level of overlap between them, as well as hardware and software capabilities. Starting from 2D aerial or terrestrial photographic images, photogrammetry allows to reconstruct a 3D model in the form of a "point cloud" and also to derive accurate 3D measurements of large architectural elements.This paper is about stereo-photogrammetric scanning by drone performed by MENCI software s.r.l. aimed at the definition of the state of conservation of the “Bridge of the Towers” in Spoleto and its long term preservation without building scaffoldings. It was performed within the RoMA (Resilience enhancement of a Metropolitan Area) project, through an agreement between the “Italian National Agency for New Technologies, Energy and Sustainable Economic Development” (ENEA) and the “Italian Ministry of Cultural Heritage and Activities” (MIBACT).Photogrammetric scanning and FE modelling were applied within the project together with many other monitoring techniques in order to assess the bridge cracks pattern and its structural health by a multidisciplinary approach that allows their mutual validation [2].As one of the most important problems in the use of photogrammetric 3D reconstruction is the considerable demand in terms of hardware and software resources for images processing and data storage, thanks to the HPC (High Performance Computing) resources provided by the CRESCO infrastructure (Research Computational Centre on Complex Systems), it was possible to analyse and process a large amount of high-resolution photos in order to detect the crack pattern and to assess the actual damage state to be monitored over time [3].

Abstract: Current practice in excavation projects is characterized by a deficient control of work progress that includes estimates of daily work progress by indirect means such as manual records of truck movements, estimates of soil swelling and occasional topographic measurements (usually at start and end of projects). In this article we propose a procedure to calculate earth work volume and progress by using geotagged digital photographs taken at the construction site. This methodology helps construction managers to improve excavation progress control and it systematizes excavation records. The procedure is grounded on literature review, the experience gained from controlled experiments and its application on a case study. With a relatively low effort (approx. 3 hrs.) the proposal enabled us to measure excavation work progress from around 50 geotagged digital photos with a precision of about 8-10% as compared to the traditional excavation volume estimate obtained from truck movement records. Best results were realized for large earth movements recorded on a weekly basis. Precision decreased for small earth movements (e.g., daily work progress control). The proposal includes recommendations for capturing the digital photos; formation of a point cloud model using photogrammetric software; formation of a mesh model and calculation of the excavation volume. Considerations for obstructing construction equipment and complex geometries are included.

Abstract: An approach to implementation of spatial navigation based on photogrammetry principles is proposed. A prototype of a tracking navigation system implementing the abovementioned approach is developed; experimental research of developed system is conducted.

Abstract: 3D printed plastic components are nowadays frequently used parts in all areas of industrial sphere. These components are often made by FDM technology. The main advantage of this technology is quick manufacturing process, price and also possibility of producing complex parts. This paper is aimed to the component made by FDM technology from the view of their strength. Specially designed chair was loaded by different force and the maximum load before destruction was measured. Chair was under inspection of two different optical strain measurement systems working on different principles. System PONTOS working on the principle of digital photogrammetry and system ARAMIS working on the principle of digital image correlation were used. These systems were used in order to investigate and identify weak places of this chair.

Abstract: CAD technology has introduced a turning point in the way of design. In the period before the introduction of computer systems, drafts were traditionally made by pen and each mistake meant erasing, whereas bigger mistakes often required re-creation of the anatomical documentation. The closely linked development of CAD/CAM technology marked the upturn in obtaining the anatomic shape and its creation. This article gives a brief insight into 3D digitization in the field of making the anatomic insole.

Abstract: These days are in the automotive industry going to be still more and more used new types of protective coatings on the Zn-Mg basis. The advantage of these coatings is their excellent protection against corrosion of basic material. On the other hand disadvantage is mainly their low formability which takes effect at own stamping process. Such paper deals with the research influence of the deformation on the damage process of this coating. Size of deformation at different stress states was measured with the help of photogrammetry (system ARAMIS). Coating damage process at these stress states was monitored by means of optical and electron microscopy. Results of protective coating Zn-Mg damage process are presented in the form of strain distribution maps and images from optical and electron microscope.