Academic literature on the topic '3DF Zephyr'

<p class="normal">The main objective of this paper is to analyse the potential as well as the limitations of an action camera (GoPro Hero 3 Black) in photogrammetric application for architectural cultural heritage reconstruction. The investigations were carried out in a site of notable historical interest, “Villa Giulia Felice” in Pompeii, Italy. In order to estimate the work pipeline, the time-consuming processing and the output product accuracy using fisheye camera images, three commercial image processing software packages were tested: Agisoft PhotoScan, Pix4Dmapper and 3DF Zephyr Aerial. Several comparisons among the final 3D models produced have been developed and the results achieved. Despite the problems found related to lens distortion and the small distance from the camera to the object (average distance ~80 cm), the test has provided good results in terms of accuracy (average error 2 - 3.5 cm) and reliability.</p>

<p><strong>Abstract.</strong> Museums and exhibits are conventionally experienced first-hand through physical interaction with the display and features. Afar from these museums, photographs and videos provide a way to view these museums, but this is an experience far from the actual physical interaction. We study in this research how 3D modelling and photogrammetry can be used to create a virtual reality (VR) environment of a university museum named Bulwagan ng Dangal in the University of the Philippines-Diliman. The main software used were 3DF Zephyr for photogrammetric modelling and AutoDesk Maya for 3D modelling of the VR environment. Models were created based of photographs taken using a DSLR camera and mobile phones. Model validation results show 2.42% to 7.00% errors. The study suggests that photogrammetric methods can be used to create a VR environment of museums or similar indoor exhibits for the purpose of experience and effective visualization.</p>

Abstract. Nowadays digital tools are booming. The evolution of the technologies used in archeology and in architecture is such that we are going more and more towards low cost and time saving. Indeed, today we can use free softwares in photogrammetry in order to make 3D surveys of architectural buildings. Fifteen years ago it only required the use of the 3D laser scanner, a very expensive technique.As part of the course reform of the second year at the national school of architecture and urban planning Tunisia in the course of descriptive geometry and perspective drawing, an experiment was conducted in order to introduce low cost photogrammetry using the free software 123 D catch by autodesk, 3DF Zephyr or Scann 3D on the mobile phone. The objective of this course is to make students experiment different techniques of representation such as photogrammetry, perspective drawing, using a mobile phone , a digital camera or a pen. The object of the representation is the Tunisian cultural heritage such as the archeological site of Carthage.

In recent years, the combination of Structure-from-Motion (SfM) algorithms and UAV-based aerial images has revolutionised 3D topographic surveys for natural environment monitoring, offering low-cost, fast and high quality data acquisition and processing. A continuous monitoring of the morphological changes through multi-temporal (4D) SfM surveys allows, e.g., to analyse the torrent dynamic also in complex topography environment like debris-flow catchments, provided that appropriate tools and procedures are employed in the data processing steps. In this work we test two different software packages (3DF Zephyr Aerial and Agisoft Photoscan) on a dataset composed of both UAV and terrestrial images acquired on a debris-flow reach (Moscardo torrent &amp;ndash; North-eastern Italian Alps). Unlike other papers in the literature, we evaluate the results not only on the raw point clouds generated by the Structure-from- Motion and Multi-View Stereo algorithms, but also on the Digital Terrain Models (DTMs) created after post-processing. Outcomes show differences between the DTMs that can be considered irrelevant for the geomorphological phenomena under analysis. This study confirms that SfM photogrammetry can be a valuable tool for monitoring sediment dynamics, but accurate point cloud post-processing is required to reliably localize geomorphological changes.

Currently, products that are obtained by Unmanned Aerial Systems (UAS) image processing based on structure-from-motion photogrammetry (SfM) are being investigated for use in high precision projects. Independent of the georeferencing process being done directly or indirectly, Ground Control Points (GCPs) are needed to increase the accuracy of the obtained products. A minimum of three GCPs is required to bring the results into a desired coordinate system through the indirect georeferencing process, but it is well known that increasing the number of GCPs will lead to a higher accuracy of the final results. The aim of this study is to find the suitable number of GCPs to derive high precision results and what is the effect of GCPs systematic or stratified random distribution on the accuracy of the georeferencing process and the final products, respectively. The case study involves an urban area of about 1 ha that was photographed with a low-cost UAS, namely, the DJI Phantom 3 Standard, at 28 m above ground. The camera was oriented in a nadiral position and 300 points were measured using a total station in a local coordinate system. The UAS images were processed using the 3DF Zephyr software performing a full BBA with a variable number of GCPs i.e., from four up to 150, while the number and the spatial location of check points (ChPs) was kept constant i.e., 150 for each independent distribution. In addition, the systematic and stratified random distribution of GCPs and ChPs spatial positions was analysed. Furthermore, the point clouds and the mesh surfaces that were automatically derived were compared with a terrestrial laser scanner (TLS) point cloud while also considering three test areas: two inside the area defined by GCPs and one outside the area. The results expressed a clear overview of the number of GCPs needed for the indirect georeferencing process with minimum influence on the final results. The RMSE can be reduced down to 50% when switching from four to 20 GCPs, whereas a higher number of GCPs only slightly improves the results.

Nowadays, Unmanned Aerial Systems (UASs) are a wide used technique for acquisition in order to create buildings 3D models, providing the acquisition of a high number of images at very high resolution or video sequences, in a very short time. Since low-cost UASs are preferred, the accuracy of a building 3D model created using this platforms must be evaluated. To achieve results, the dean's office building from the Faculty of “Hydrotechnical Engineering, Geodesy and Environmental Engineering” of Iasi, Romania, has been chosen, which is a complex shape building with the roof formed of two hyperbolic paraboloids. Seven points were placed on the ground around the building, three of them being used as GCPs, while the remaining four as Check points (CPs) for accuracy assessment. Additionally, the coordinates of 10 natural CPs representing the building characteristic points were measured with a Leica TCR 405 total station. The building 3D model was created as a point cloud which was automatically generated based on digital images acquired with the low-cost UASs, using the image matching algorithm and different software like 3DF Zephyr, Visual SfM, PhotoModeler Scanner and Drone2Map for ArcGIS. Except for the PhotoModeler Scanner software, the interior and exterior orientation parameters were determined simultaneously by solving a self-calibrating bundle adjustment. Based on the UAS point clouds, automatically generated by using the above mentioned software and GNSS data respectively, the parameters of the east side hyperbolic paraboloid were calculated using the least squares method and a statistical blunder detection. Then, in order to assess the accuracy of the building 3D model, several comparisons were made for the facades and the roof with reference data, considered with minimum errors: TLS mesh for the facades and GNSS mesh for the roof. Finally, the front facade of the building was created in 3D based on its characteristic points using the PhotoModeler Scanner software, resulting a CAD (Computer Aided Design) model. The results showed the high potential of using low-cost UASs for building 3D model creation and if the building 3D model is created based on its characteristic points the accuracy is significantly improved.

L'elaborato descrive le capacità di vari software di aerofotogrammetria testati con relativa comparazione dei risultati, descrizione degli errori, caratterizzazione delle ottiche delle camera da presa utilizzate. All'inizio dell'elaborato è fornita un'introduzione teorica degli aspetti fondamentali dell'aerofotogrammetria.