scholarly journals SPICE-Based SAR Tomography Over Forest Areas Using a Small Number of P-band Airborne F-SAR Images Characterized by Non-Uniformly Distributed Baselines

2019 ◽  
Vol 11 (8) ◽  
pp. 975 ◽  
Author(s):  
Peng ◽  
Li ◽  
Wang ◽  
Zhu ◽  
Liang ◽  
...  

Synthetic aperture radar tomography (TomoSAR) has been proven to be a useful way to reconstruct vertical structure over forest areas with P-band images, on account of its three-dimensional imaging ability. In the case of a small number of non-uniformly distributed acquisitions, compressive sensing (CS) is generally adopted in TomoSAR. However, the performance of CS depends on the selected hyperparameter, which is closely related to the noise of a pixel. In this paper, to overcome this limitation, we propose a sparse iterative covariance-based estimation (SPICE) approach based on the wavelet and orthogonal sparse basis (W&O-SPICE) for application over forest areas. SPICE is a sparse spectral estimation method that achieves a high vertical resolution, and takes account of the noise adaptively for each resolution cell. Thus, it does not require the user to select a hyperparameter. Furthermore, the used sparse basis not only ensures the sparsity of the forest canopy scattering contribution, but it can also keep the original sparse information of the ground contribution. The proposed method was tested in simulated experiments and the results demonstrated that W&O-SPICE can successfully reconstruct the vertical structure of a forest. Moreover, three P-band fully polarimetric airborne SAR images with non-uniformly distributed baselines were applied to reconstruct the vertical structure of a tropical forest in Mabounie, Gabon. The underlying topography and forest height were estimated, and the root-mean-square errors (RMSEs) were 6.40 m and 4.50 m with respect to the LiDAR digital terrain model (DTM) and canopy height model (CHM), respectively. In addition, W&O-SPICE showed a better performance than W&O-CS, beamforming, Capon, and the iterative adaptive approach (IAA).

2014 ◽  
Vol 587-589 ◽  
pp. 1091-1094
Author(s):  
Xi Sheng ◽  
Hua Peng Luo ◽  
Ping Wang

Belonging to the Bentley Microstation series which work as one of the BIM platforms, the Bentley Power Rail Track shows huge advantages in the railway design for its visibility, high efficiency, advance, reliability and so on. This paper introduces the way to build the digital terrain model, alignments, cross sections, turnouts and to display the three-dimensional model of the railway for the Bentley Power Rail Track 3D railway design software. It provides application preparation for the BIM railway design and achieves the preliminary exploration of BIM applications. Bentley Power Rail Track proves capable of the BIM railway design.


2021 ◽  
Vol 93 ◽  
pp. 05007
Author(s):  
Elena Sazonova ◽  
Veronica Borisova ◽  
Sergey Terentyev ◽  
Olga Kramlikh ◽  
Irina Sidorenkova

One of the topical trends in the development of agriculture in the Russian Federation is digitalization and automation of methods for processing spatial information about various land resources. The main element of the implementation of this direction in practice can be considered a three-dimensional digital terrain model. This model allows solving many problems in the field of land management, in particular, such as analyzing the surface of the terrain in order to determine its suitability for agricultural production. Despite a number of existing problems in this area, an automated digital land management system will enable public authorities to implement an integrated and systematic approach to management, that is, to more efficiently use the land resources, influence the land market, as well as attract the investments and create the necessary conditions. for sustainable development of the territory.


2014 ◽  
Vol 1044-1045 ◽  
pp. 1278-1282
Author(s):  
Xing Guo Qiu ◽  
Zheng Liu

Aiming at the folds caused by the sparse data in the process of DTM (Digital Terrain Model), this article proposed a method of interpolating spatial control points based on Delaunay triangulation and Kriging interpolation algorithm. The terrain data of an area with complex terrain in Xianyang was used to construct terrain model according to the proposed algorithm. Experimental results show that the method can finish the interpolation of the terrain denser data quickly and accurately, and it provides an efficient technological tool for building a true three-dimensional terrain model.


2021 ◽  
Vol 12 (25) ◽  
pp. 158
Author(s):  
Pablo Aparicio-Resco ◽  
Alejandro García Álvarez-Busto ◽  
Iván Muñiz-López ◽  
Noelia Fernández-Calderón

<p class="VARKeywords">The virtual reconstruction of a site is the mirror in which the archaeological research process is reflected, with all its uncertainties and certainties, generating a space for reflection on the lost materiality while the vestige itself is reconfigured into a didactic and social resource. Here we present the result of the three-dimensional (3D) reconstruction of the archaeological structures preserved in the Peñón de Raíces, in Castrillón (Asturias), which correspond to the ruins of the castle of Gauzón, a famous fortification of the Asturian kings in which La Cruz de la Victoria was made in 908.</p><p>The article begins with an introduction and a first part (Section 2) dedicated to the explanation of the site itself from an archaeological and historical point of view. We believe that this analysis should be the basis of any scientific virtual reconstruction. The virtual reconstruction presented here is dated to the 9-10th centuries and corresponds to the fortification built in the time of the Asturian kings. We offer a detailed analysis of the morphological and architectural components that have been documented in this defensive settlement in the light of archaeological research, and that provide the main foundations for the infographic reconstruction.</p><p>In the second part of the article (Section 3), we analyse the specific sources of historical and archaeological information that support the reconstruction and serve as a reference for it. The historical-archaeological sources used for the representation, for example, of the walls and the palaeoenvironmental environment, are detailed. Likewise, we comment on the process of discussion of the different hypotheses that, finally, lead to the presented result. It is important to note that without this discussion process it is not possible to produce a sound and solid proposal over time.</p><p>In the third part (Section 4), we show the result of the virtual reconstruction with a series of images. To obtain the virtual reconstruction presented in this article, the Blender Geographic Information System (GIS) addon has been used, which allows us to have a digital terrain model (DTM) on our 3D desktop easily so that we can begin to carry out the work from it. The archaeological planimetries were arranged on it and, based on all this information, the modelling process began. In the first place, basic modelling of volumes was carried out that served to raise the first sketches and, on them, to continue discussing the reconstructive hypotheses. Little by little the geometry of the virtual reconstruction was detailed and the castle took shape. The next step was to carry out texturing in a photorealistic way, for which it was decided to use Substance Painter software. We continued with the texturing and addition of details of the surrounding terrain using particle systems, which has been one of the most complex phases to carry out given the level of realism that we set ourselves as a goal. Later, other types of minor details were added: objects, characters and animals, which help to better understand the context. Finally, the final renderings are carried out and their post-processing is developed in Adobe Photoshop, for which matte painting techniques were used that merge 3D images with photographs and digital drawing.</p><p>Our interest was to carry out scientific graphic work, for which we have emphasized the importance of using the scale depicting historical/archaeological evidence for virtual reconstructions, a tool that allows us to ensure the principles of authenticity and scientific transparency of any virtual reconstruction (Aparicio et al., 2016). In this case, thanks to this tool, it is clear that the highest level of evidence is found in the castle itself excavated in the acropolis, while the town and the surrounding palisade clearly show a lower level of evidence. We hope that subsequent excavations in this area will allow us to review the reconstruction and thus also reflect a higher level of evidence in this area.</p><p>We believe that the work presented here constitutes a good example of the use of virtual scientific reconstruction for the development and consolidation of new hypotheses not only reconstructive but also interpretive of an archaeological site. Furthermore, the result presented here demonstrates the power of this graphic resource for the dissemination of historical-archaeological knowledge, a fundamental objective when carrying out any scientific work.</p><p><strong>Highlights:</strong></p><ul><li><p>Reconstrucción infográfica de una de las principales fortificaciones del reino de Asturias (s. VIII-X), a partir de la evidencia material documentada en las campañas de excavación arqueológica realizadas en el yacimiento.</p></li><li><p>Desarrollo de hipótesis reconstructivas de arquitectura militar altomedieval arruinada mediante la interpretación de vestigios arqueológicos aplicando un enfoque multidisciplinar.</p></li><li><p>Ejemplo de uso de la escala de evidencia histórico-arqueológica y de las unidades reconstructivas (UR) como instrumentos que permiten garantizar los principios de autenticidad y transparencia científica.</p></li></ul>


2021 ◽  
Vol 18 (2) ◽  
pp. 67
Author(s):  
MUHAMMAD HAFIZ AIZUDDIN BIN MOHD ZAIDI ◽  
Khairul Nizam Tahar

UAV or drone application of autonomy ranging can be divided into several levels, from basic hovering and position over trajectory tracking and waypoint navigation to fully autonomous navigation. This study used the DroneDeploy application for an autonomous flight mission. It is the process of taking photographs from an aircraft or other flying objects with a camera mounted on them to produce a three-dimensional (3D) map from the images captured, including a digital terrain model (DTM) and orthophotos. As for this study, the same output will be generated, but different flight parameter applications were used. Therefore, the study determined the optimum number of ground control points (GCPs) and evaluated the accuracy of the final results for each flight design. Acquired data were processed using the Pix4D modeller software due to the user-friendly factor and faster processing rate offered by the software. The results were analysed, and recommendations were made for future study improvement and to avoid similar problems. This study is useful for the mapping industry to achieve high accuracy results.  Keywords: Aerial photogrammetry, Flight Parameter, UAV apps, DTM, Orthophotos, GCPs


2021 ◽  
Vol 50 (1) ◽  
pp. 75-89
Author(s):  
Mark Abolins ◽  
Albert Ogden

A novel method to map and quantitatively describe very gentle folds (limb dip <5°) at cratonic cave sites was evaluated at Snail Shell and Nanna caves, central Tennessee, USA. Elevations from the global SRTM digital terrain model (DTM) were assigned to points on late Ordovician geologic contacts, and the elevations of the points were used to interpolate 28 m cell size natural neighbor digital elevation models (DEM’s) of the contacts. The global Forest Canopy Height Dataset was subtracted from the global 28 m cell size AW3D30 digital surface model (DSM) to create a DTM, and that DTM was applied in the same way. Comparison of mean and modal strikes of the interpolated surfaces with mean and modal cave passage trend shows that many passages are sub-parallel to the trend of an anticline. WithiSn 500 m of the caves, the SRTM- and AW3D30-based interpolated surfaces have mean strikes within 8° of the mean strike of an interpolated reference surface created with a high resolution (~0.76 m cell size and 10 cm RMSE) Tennessee, USA LiDAR DTM. This evaluation shows that the SRTM- and AW3D30-based method has the potential to reveal a relationship between the trend of a fold, on one hand, and cave passages, on the other, at sites where a geologic contact varies in elevation by >35 m within an area of <12.4 km2 and the mean dip of bedding is >0.9°.


Author(s):  
Oyunkhand Byamba ◽  
◽  
Elena L. Kasyanova ◽  

The development of science always depends on technological progress. Cartography is rapidly changing and developing with the introduction of new computer technologies, such as GIS and remote sensing of the Earth. Recently, there have been qualitatively new types of cartographic products, in particular 3D terrain models, which in cartography are becoming a universal, optimal and operational method for displaying terrain. The article discusses a method for creating a three-dimensional digital terrain model in the form of an irregular triangulation network based on SRTM data and GIS technology on the example of the Khenti aimag of Eastern Mongolia.


2012 ◽  
Vol 256-259 ◽  
pp. 179-182
Author(s):  
Peng Ran Song ◽  
Chang Ming Wang

Research the structure changes before and after collapsible experiment of loess microstructure. Using artificial preparation methods prepared different moisture samples of Liaoxi loess. Do collapsible test and Scanning electron microscope test with the prepared samples. According to Digital Terrain Model theory, three-dimensional porosities were calculated based on gray scale information from the SEM images extracted by MATLAB. The results are shown following as: the microstructure of loess samples is getting dense, the average number of pore of samples obviously increases and the pore area decreases after the sample is collapsed. The distribution before and after the collapsibility of gray value has certain regularity. The before one has double peaks, large distribution. The after one has single peak, concentrate distribution and meets normal distribution.


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