An Adaptive Multi‐Grid Solver for Applications in Computer Graphics

Kazhdan, Michael; Hoppe, Hugues

doi:10.1111/cgf.13449

Cited by 20 publications

(15 citation statements)

References 35 publications

(72 reference statements)

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“…We used the surface reconstruction method, which fits a mesh on the 3D point cloud density of each plot (the filtered point clouds and not voxel grids) (Attene & Spagnuolo, 2000). We applied the Poisson surface reconstruction method, which fits a mesh on all oriented points (perpendicular vectors to the tangential plane to the surface at that point) (Kazhdan & Hoppe, 2019). Poisson surface reconstruction is the preferred method for TLS data due to its stability and reliability (Berger et al., 2014; Gupta & Shukla, 2018).…”

Section: Methodsmentioning

confidence: 99%

Biodiversity facets affect community surface temperature via 3D canopy structure in grassland communities

et al. 2021

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Canopy structure is an important driver of the energy budget of grassland ecosystem and is, at the same time, altered by plant diversity. Diverse plant communities typically have taller and more densely packed canopies than less diverse communities. With this, they absorb more radiation, have a higher transpiring leaf surface and are better coupled to the atmosphere which leads to cooler canopy surfaces. However, whether plant diversity generally translates into a cooling potential remains unclear and lacks empirical evidence. Here, we assessed how functional identity, functional diversity and species richness of grassland communities in the Jena Experiment predict the mean and variation of plant surface temperature mediated via effects of canopy structure. Using terrestrial laser scanning, we estimated canopy structure describing metrics of vertical structure (mean height, LAI), the distribution (evenness) and the highest allocation (centre of gravity) of biomass along height strata. As metrics of horizontal structure, we considered community stand gaps, canopy surface variation and emergent flowers. We measured surface temperature with a thermal camera. We used SEM models to predict biodiversity effects on the surface temperature during two seasonal peaks of biomass. Before the first cut in May, herb‐dominated communities directly promoted lower leaf surface temperatures. However, communities with lower centre of gravity (mostly herb dominated) also increased canopy surface temperatures compared with grass‐dominated communities with higher biomass stored in the top canopy. Grass‐dominated communities showed a smaller variation of surface temperatures, which was also positively affected by species richness via an increase in mean height. In August, mean surface temperature decreased with increasing community CC and LAI. The variation of surface temperature was greater in herb‐dominated than in grass‐dominated communities and increased with plant species richness (direct effects). Synthesis. The mean and variation of canopy surface temperature were driven by differences in functional group composition (herbs‐ vs. grass dominance) and to a lesser extent by plant diversity. These effects were partly mediated the metrics of canopy structure but also by direct effects unrelated to the structural metrics considered.

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Section: Methodsmentioning

confidence: 99%

Biodiversity facets affect community surface temperature via 3D canopy structure in grassland communities

et al. 2021

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“…Moreover, linear system solvers are important for image processing as these transform linear equations into discrete ones and are often employed in very specific scenarios like image stitching where its solutions are evaluated near the connections of two images. with this in mind, an adaptive, efficient solver was developed in [102] to help solve random levels of a number of finite elements, in symmetric systems, which allows random dimensions and is able to support integral and pointwise constraints.…”

Section: Isosurface Extractionmentioning

confidence: 99%

“…The dimensionality is allowed by integration and evaluation is separated and performed over the existing dimensions using dimensional windows, neighbor lookups, and template specialization. The constraints are supported by allowing the user to impose the coefficients of functions in relation to the B-Spline levels [102].…”

Section: Isosurface Extractionmentioning

confidence: 99%

How to Build a 2D and 3D Aerial Multispectral Map?—All Steps Deeply Explained

Vong

Matos-Carvalho

Toffanin³

et al. 2021

Remote Sensing

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The increased development of camera resolution, processing power, and aerial platforms helped to create more cost-efficient approaches to capture and generate point clouds to assist in scientific fields. The continuous development of methods to produce three-dimensional models based on two-dimensional images such as Structure from Motion (SfM) and Multi-View Stereopsis (MVS) allowed to improve the resolution of the produced models by a significant amount. By taking inspiration from the free and accessible workflow made available by OpenDroneMap, a detailed analysis of the processes is displayed in this paper. As of the writing of this paper, no literature was found that described in detail the necessary steps and processes that would allow the creation of digital models in two or three dimensions based on aerial images. With this, and based on the workflow of OpenDroneMap, a detailed study was performed. The digital model reconstruction process takes the initial aerial images obtained from the field survey and passes them through a series of stages. From each stage, a product is acquired and used for the following stage, for example, at the end of the initial stage a sparse reconstruction is produced, obtained by extracting features of the images and matching them, which is used in the following step, to increase its resolution. Additionally, from the analysis of the workflow, adaptations were made to the standard workflow in order to increase the compatibility of the developed system to different types of image sets. Particularly, adaptations focused on thermal imagery were made. Due to the low presence of strong features and therefore difficulty to match features across thermal images, a modification was implemented, so thermal models could be produced alongside the already implemented processes for multispectral and RGB image sets.

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“…Conceptually different approaches include the popular Screened Poisson Surface Reconstruction (SPSR) [24][25][26][27], which is probably one of the most commonly used point cloud reconstruction methods. In direct comparison, however, SPSR tends to produce rather smoothed out results, whereas ours generally appear sharper and capture finer details, even at lower resolution.…”

Section: Related Workmentioning

confidence: 99%

Be water my friend: mesh assimilation

Bukenberger

Lensch

2021

Vis Comput

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Inspired by the ability of water to assimilate any shape, if being poured into it, regardless if flat, round, sharp, or pointy, we present a novel, high-quality meshing method. Our algorithm creates a triangulated mesh, which automatically refines where necessary and accurately aligns to any target, given as mesh, point cloud, or volumetric function. Our core optimization iterates over steps for mesh uniformity, point cloud projection, and mesh topology corrections, always guaranteeing mesh integrity and $$\epsilon $$ ϵ -close surface reconstructions. In contrast with similar approaches, our simple algorithm operates on an individual vertex basis. This allows for automated and seamless transitions between the optimization phases for rough shape approximation and fine detail reconstruction. Therefore, our proposed algorithm equals established techniques in terms of accuracy and robustness but supersedes them in terms of simplicity and better feature reconstruction, all controlled by a single parameter, the intended edge length. Due to the overall increased versatility of input scenarios and robustness of the assimilation, our technique furthermore generalizes multiple established approaches such as ballooning or shrink wrapping.

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An Adaptive Multi‐Grid Solver for Applications in Computer Graphics

Cited by 20 publications

References 35 publications

Biodiversity facets affect community surface temperature via 3D canopy structure in grassland communities

Biodiversity facets affect community surface temperature via 3D canopy structure in grassland communities

How to Build a 2D and 3D Aerial Multispectral Map?—All Steps Deeply Explained

Be water my friend: mesh assimilation

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