Jul 2026· The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences· 0 citations· 24 references
Abstract
Abstract. High-resolution 3D documentation of cultural heritage sites is essential for their preservation. While terrestrial laser scanning (TLS) remains the gold standard, it is often cost-intensive compared to photogrammetry. This study evaluates three image-based reconstruction techniques, Multi-View Stereo (MVS), Neural Radiance Fields (NeRF) and 3D Gaussian Splatting (3DGS), by applying them to a complex scene featuring a chapel and its surrounding vegetation, sensed from an uncrewed aerial vehicle (UAV). A hybrid TLS/MVS model provides a high-accuracy reference. Using identical interior and exterior camera parameters of the 105 UAV-acquired images, we generate dense point clouds with all methods and assess geometric accuracy and completeness using the M3C2 algorithm. Results show that MVS achieves superior accuracy (standard deviation of all M3C2 distances: MVS = 0.11 m, NeRF = 0.15 m), whereas NeRF attains up to 20% higher completeness, particularly in low-texture and vegetation-occluded regions. The 3DGS point cloud was deemed too sparse and was therefore not used for further analysis. The study highlights the potential of NeRFs to recover partially occluded or sparsely textured geometries that are challenging for MVS and suggests a complementary use of both approaches for cost-efficient documentation of cultural heritage.
Abstract. The 3D documentation of complex scenes—characterized by restricted spaces, irregular geometries, and poor lighting—remains a significant challenge in cultural heritage. This study proposes a rapid data acquisition methodology based on the multi-sensor fusion of Terrestrial Laser Scanning (TLS) and Spherical Photogrammetry (SP). The approach was validated in two distinct complex environments: an ancient Egyptian rock-cut tomb (QH36, Aswan, Egypt) and a natural Iberian sanctuary cave (Cueva de la Lobera, Jaén, Spain). The methodology uses TLS to establish a high-precision geometric backbone, achieving registration errors below 0.5 cm. By extracting Ground Control Points (GCPs) directly from the TLS point cloud, the reliance on traditional total station surveying was significantly reduced, enhancing fieldwork efficiency. SP was implemented to obtain realistic textures and to support geometry by using a 360-degree multi-camera with integrated LED lighting, providing full spherical coverage and high-resolution textures. Results indicate that SP is at least six times faster than conventional photogrammetry. Furthermore, the use of TLS-derived meshes enabled advanced digital masking to remove non-interest objects (e.g., archaeological equipment) from the final models. While conventional photogrammetry remains the benchmark for fine architectural details, this research demonstrates that the TLS-SP fusion is the most viable solution for the rapid, high-accuracy documentation of constrained heritage sites. This hybrid workflow ensures geometric integrity while drastically reducing acquisition times, providing a robust framework for future archaeological and conservation projects.
A. Mozas-Calvache, José Luis Pérez-García, J. M. Gómez-López et al.· The International Archives o...· 0 citations
This study evaluates the metric reliability of nadir and hybrid RTK-UAV photogrammetric models for surface detail extraction on a two-story building without using Ground Control Points (GCPs). Two photogrammetric models were generated: a standard model based only on nadir images and a hybrid model combining nadir, oblique, and manual façade-oriented images. Both models were assessed using terrestrial reference data obtained from GNSS and reflector less total station measurements. The evaluation was performed at three levels: point-based, length-based, and surface-based comparisons. The point-based results indicate that the nadir model allowed 21 of the 35 reference points to be reconstructed, whereas the hybrid model allowed the 3D positions of all. The hybrid model also substantially improved vertical and overall 3D accuracy, reducing the ΔZ MAE from 0.355 m to 0.029 m and the 3D RMSE from 0.454 m to 0.046 m. In the length-based analysis, the nadir model was included where both endpoints of a selected linear element could be clearly identified. The nadir model allowed only 4 of the 14 selected length pairs to be measured, whereas the hybrid model allowed all 14 length pairs to be evaluated. On the other hand, the hybrid model had close agreement with the reference lengths, with a MAE of 0.012 m and RMSE of 0.016 m. Also, there is no statistically significant difference observed between reference and model lengths. In the surface-based comparison, the nadir model could represent only 4 of 7 reference surfaces, a limited number of reference surfaces, whereas the hybrid model enabled all selected surfaces to be evaluated, including upper-floor and under-eave regions. Although the nadir model produced lower average errors on some reconstructed surfaces, its limited surface coverage reduced its practical applicability. Overall, the findings demonstrate that hybrid RTK-UAV image acquisition provides a more robust and reliable solution than nadir-only acquisition for building surface documentation, particularly in façade areas with restricted visibility.
M. N. Alkan· International Journal of Geo...· 0 citations
Although accuracy is still insufficient for demanding metric applications, the results support the use of MDE as a complementary source for thematic interpretation, scene understanding, robotics, navigation, and related tasks where strict geometric precision is not required.
F. Chiabrando, Francesca Gallitto, A. Lingua et al.· The International Archives o...· 0 citations
This study presents a UAV photogrammetry and GIS-based workflow for generating high-accuracy three-dimensional cadastral models in urban environments. The proposed framework integrates RTK-enabled UAV image acquisition, ground control point (GCP) surveying, photogrammetric reconstruction, GIS-based spatial data management, and accuracy assessment within a unified workflow. A total of 454 aerial images were acquired and processed to generate a dense point cloud, digital surface model, orthomosaic, and textured 3D urban model. Positional accuracy was evaluated using 15 independently surveyed RTK GNSS checkpoints distributed throughout the study area. The results demonstrated a relative accuracy of 1.7 cm and an absolute positional accuracy of 2.47 cm based on independent checkpoint validation, confirming the suitability of the proposed workflow for large-scale cadastral mapping applications. The generated 3D cadastral model enabled accurate extraction and visualization of parcel boundaries, building footprints, and urban spatial features. The findings indicate that UAV photogrammetry combined with GIS provides a cost-effective and reliable approach for developing high-precision three-dimensional cadastral datasets that support modern land administration, urban planning, and digital city management.
Salar Mirzapour, Z. Azizi, H. Zavar et al.· Scientific Reports· 0 citations
Abstract. The proliferation of continuous Neural Radiance Field (NeRF) and 3D Gaussian Splatting (3DGS) has shifted the paradigm of 3D aerial reconstruction from relying solely on geometric stereo matching to inverse rendering optimization. However, while these emerging rendering-based frameworks excel in synthesizing photo-realistic novel views, their capability to extract accurate surfaces in complex aerial scenarios remains ambiguous compared to traditional methods. To establish a clearer understanding, this study presents a comprehensive evaluation of five representative frameworks spanning traditional Structure from Motion (SfM), purely Signed Distance Field (SDF) representations, unstructured 3D Gaussians, hybrid voxel-Gaussians, and strictly explicit sparse voxels. By systematically standardizing identical computational environments, inputs, and unified mesh-extraction pipelines on both real-world airborne LiDAR datasets and synthetic cityscapes, we assess their performance regarding visual fidelity, geometric accuracy, and resource efficiency. The experimental results reveal that while traditional MVS produces the highest overall geometric precision by strictly enforcing multi-view rigid geometry, it is prone to failures in texture-less regions. Among rendering-based representations, a fundamental trade-off exists: highly flexible, unstructured 3DGS achieve highest visual scores but degrade the underlying geometric surfaces; conversely, explicitly structured techniques demonstrate distinct superiority in regularizing topological coherence and floating artifact suppression. Furthermore, we observe that integrating structured voxels avoids the severe memory bottlenecks associated with extracting geometries from chaotic unorganized primitives. These empirical findings emphasize that for large-scale aerial photogrammetry, integrating explicit spatial structuralization into differentiable rendering pipelines is imperative for achieving scalable operations and bridging the geometric accuracy gap with traditional methods.
Shihan Chen, Zhaojin Li, Q. Yan et al.· The International Archives o...· 0 citations
Abstract. Three-dimensional (3D) modeling for the documentation, preservation, and management of cultural heritage is indispensable. To achieve this goal, a low-cost unmanned aerial vehicle (UAV) combined with the Structure from Motion (SfM) photogrammetric technique was utilized to build a 3D model and conduct surface crack measurements of cultural monuments. The results showed that, under simple conditions, non-specialists can easily generate accurate 3D models from UAV-acquired imagery. In this study, the statistical errors of checkpoints between 3D reconstruction and field measurements, expressed as total RMSE, ranged from 0.103 m to 0.848 m. However, the mean absolute errors of surface crack measurements between tape-based methods and 3D reconstruction ranged from 0.002 m to 0.099 m. Furthermore, UAV-SfM was applied to measure surface crack lengths on an inaccessible cultural monument. The findings demonstrated that employing the UAV-SfM photogrammetric technique for 3D reconstruction of cultural monuments is both feasible and reliable.
Wei-Che Huang, Wen-Cheng Liu, Yi-Shan Luo et al.· The International Archives o...· 0 citations
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