Evaluation of Three-Dimensional Leaf Distribution within a Closed Canopy Based on Low-Cost Laser Scanning Data during Leafless Season

In recent decades, 3D acquisition by laser scanning or digital photogrammetry has become one of the standard methods of documenting cultural heritage, because it permits one to analyze the shape, geometry, and location of any artefact without necessarily coming into contact with it. The recording of three-dimensional metrical data of an asset allows one to preserve and monitor, but also to understand and explain the history and cultural heritage shared. In essence, it constitutes a digital archive of the state of an artefact, which can be used for various purposes, be remodeled, or kept safely stored. With the introduction of 3D printing, digital data can once again take on material form and become physical objects from the corresponding mathematical models in a relatively short time and often at low cost. This possibility has led to a different consideration of the concept of virtual data, no longer necessarily linked to simple visual fruition. The importance of creating high-resolution physical copies has been reassessed in light of different types of events that increasingly threaten the protection of cultural heritage. The aim of this research is to analyze the critical issues in the production process of the replicas, focusing on potential problems in data acquisition and processing and on the accuracy of the resulting 3D printing. The metric precision of the printed model with 3D technology are fundamental for everything concerning geomatics and must be related to the same characteristics of the digital model obtained through the survey analysis.

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Assessing the Orange Tree Crown Volumes Using Google Maps as a Low-Cost Photogrammetric Alternative

Agronomy ◽

10.3390/agronomy10060893 ◽

2020 ◽

Vol 10 (6) ◽

pp. 893 ◽

Cited By ~ 1

Author(s):

Carmen Marín-Buzón ◽

Antonio Pérez-Romero ◽

Fabio Tucci-Álvarez ◽

Francisco Manzano-Agugliaro

Keyword(s):

Laser Scanning ◽

Low Cost ◽

Three Dimensional ◽

Average Error ◽

Tree Crown ◽

High Definition ◽

Google Maps ◽

Traditional Methods ◽

Aerial Photogrammetry ◽

Dimensional Approximation

The accurate assessment of tree crowns is important for agriculture, for example, to adjust spraying rates, to adjust irrigation rates or even to estimate biomass. Among the available methodologies, there are the traditional methods that estimate with a three-dimensional approximation figure, the HDS (High Definition Survey), or TLS (Terrestrial Laser Scanning) based on LiDAR technology, the aerial photogrammetry that has re-emerged with unmanned aerial vehicles (UAVs), as they are considered low cost. There are situations where either the cost or location does not allow for modern methods and prices such as HDS or the use of UAVs. This study proposes, as an alternative methodology, the evaluation of images extracted from Google Maps (GM) for the calculation of tree crown volume. For this purpose, measurements were taken on orange trees in the south of Spain using the four methods mentioned above to evaluate the suitability, accuracy, and limitations of GM. Using the HDS method as a reference, the photogrammetric method with UAV images has shown an average error of 10%, GM has obtained approximately 50%, while the traditional methods, in our case considering ellipsoids, have obtained 100% error. Therefore, the results with GM are encouraging and open new perspectives for the estimation of tree crown volumes at low cost compared to HDS, and without geographical flight restrictions like those of UAVs.

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Software-Based Three-Dimensional Deconvolution Microscopy of Cytoskeletal Proteins in Cultured Fibroblast Using Open-Source Software and Open Hardware

Journal of Imaging ◽

10.3390/jimaging5120088 ◽

2019 ◽

Vol 5 (12) ◽

pp. 88

Author(s):

Kazuo Katoh

Keyword(s):

Open Source ◽

Open Source Software ◽

Laser Scanning ◽

Low Cost ◽

Three Dimensional ◽

Cytoskeletal Proteins ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Actual Measurement ◽

Open Hardware

As conventional fluorescence microscopy and confocal laser scanning microscopy generally produce images with blurring at the upper and lower planes along the z-axis due to non-focal plane image information, the observation of biological images requires “deconvolution.” Therefore, a microscope system’s individual blur function (point spread function) is determined theoretically or by actual measurement of microbeads and processed mathematically to reduce noise and eliminate blurring as much as possible. Here the author describes the use of open-source software and open hardware design to build a deconvolution microscope at low cost, using readily available software and hardware. The advantage of this method is its cost-effectiveness and ability to construct a microscope system using commercially available optical components and open-source software. Although this system does not utilize expensive equipment, such as confocal and total internal reflection fluorescence microscopes, decent images can be obtained even without previous experience in electronics and optics.

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TRIANGULATION AND TIME-OF-FLIGHT BASED 3D DIGITISATION TECHNIQUES OF CULTURAL HERITAGE STRUCTURES

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xliii-b2-2021-825-2021 ◽

2021 ◽

Vol XLIII-B2-2021 ◽

pp. 825-830

Author(s):

C. Altuntas

Keyword(s):

Cultural Heritage ◽

Laser Scanning ◽

Low Cost ◽

Measurement Techniques ◽

Three Dimensional ◽

Laser Scanner ◽

Time Of Flight ◽

Cost Effective ◽

Cloud Data ◽

Dense Point

Abstract. This study aims to introduce triangulation and ToF measurement techniques used in three-dimensional modelling of cultural heritages. These measurement techniques are traditional photogrammetry, SfM approach, laser scanning and time-of-flight camera. The computer based approach to photogrammetric measurement that is named SfM creates dense point cloud data in a short time. It is low-cost and very easy to application. However traditional photogrammetry needs a huge effort for creating 3D wire-frame model. On the other hand active measurement techniques such as terrestrial laser scanner and time-of-flight camera have also been used in three-dimensional modelling for more than twenty years. Each one has specific accuracy and measurement effectiveness. The large or small structures have different characters, and require proper measurement configurations. In this study, after these methods are introduced, their superior and weak properties in cultural heritage modelling to make high accuracy, high density and labour and cost effective measurement.

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Replica Fabrication of a Greek Paleontological Find Utilising Laser Scanning and Fused Deposition Modeling

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.657.795 ◽

2014 ◽

Vol 657 ◽

pp. 795-799 ◽

Cited By ~ 1

Author(s):

Anastasios Chatzikonstantinou ◽

Dimitrios Tzetzis ◽

Panagiotis Kyratsis ◽

Nikolaos Bilalis

Keyword(s):

Point Cloud ◽

Laser Scanning ◽

Fused Deposition Modeling ◽

Complex Geometry ◽

Low Cost ◽

Three Dimensional ◽

Laser Scanner ◽

Analytical Methodology ◽

Fused Deposition ◽

Deposition Modeling

The current work demonstrates a feasibility study on the generation of a copy, having a highly complex geometry, of a Greek paleontological find utilising reverse engineering and low-cost rapid prototyping techniques. A part of the jaw bone of a cave bear (Ursus spelaeus) that lived during the Pleistocene and became extinct about 10,000 years ago was digitized using a three-dimensional laser scanner. The resulting point-cloud of the scans was treated with a series of advanced software for the creation of surfaces and ultimately for a digital model. The generated model was three-dimensionally built by the aid of a Fused Deposition Modeling (FDM) apparatus. An analytical methodology is presented revealing the step by step approach from the scanning to the prototyping. It is believed that a variety of interested parties could benefit from such an analytical approach, including, production engineers, three-dimensional CAD users and designers, paleontologists and museum curators.

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Accuracy Evaluation of Videogrammetry Using A Low-Cost Spherical Camera for Narrow Architectural Heritage: An Observational Study with Variable Baselines and Blur Filters

Sensors ◽

10.3390/s19030496 ◽

2019 ◽

Vol 19 (3) ◽

pp. 496 ◽

Cited By ~ 4

Author(s):

Zheng Sun ◽

Yingying Zhang

Keyword(s):

Laser Scanning ◽

Low Cost ◽

Three Dimensional ◽

Ground Truth ◽

3D Models ◽

Accuracy Evaluation ◽

Architectural Heritage ◽

Video Frames ◽

Image Pairs ◽

Spherical Camera

Three-dimensional (3D) reconstruction using video frames extracted from spherical cameras introduces an innovative measurement method in narrow scenes of architectural heritage, but the accuracy of 3D models and their correlations with frame extraction ratios and blur filters are yet to be evaluated. This article addresses these issues for two narrow scenes of architectural heritage that are distinctive in layout, surface material, and lighting conditions. The videos captured with a hand-held spherical camera (30 frames per second) are extracted to frames with various ratios starting from 10 and increasing every 10 frames (10, 20, …, n). Two different blur assessment methods are employed for comparative analyses. Ground truth models obtained from terrestrial laser scanning and photogrammetry are employed for assessing the accuracy of 3D models from different groups. The results show that the relative accuracy (median absolute errors/object dimensions) of spherical-camera videogrammetry range from 1/500 to 1/2000, catering to the surveying and mapping of architectural heritage with medium accuracy and resolution. Sparser baselines (the length between neighboring image pairs) do not necessarily generate higher accuracy than those from denser baselines, and an optimal frame network should consider the essential completeness of complex components and potential degeneracy cases. Substituting blur frames with adjacent sharp frames could reduce global errors by 5–15%.

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Underwater High-Precision 3D Reconstruction System Based on Rotating Scanning

Sensors ◽

10.3390/s21041402 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1402

Author(s):

Qingsheng Xue ◽

Qian Sun ◽

Fupeng Wang ◽

Haoxuan Bai ◽

Bai Yang ◽

...

Keyword(s):

3D Reconstruction ◽

High Precision ◽

Laser Scanning ◽

Low Cost ◽

Three Dimensional ◽

Reconstruction Error ◽

Scanning System ◽

Standard Sphere ◽

Underwater Camera ◽

The Impact

This paper presents an underwater high-precision line laser three-dimensional (3D) scanning (LLS) system with rotary scanning mode, which is composed of a low illumination underwater camera and a green line laser projector. The underwater 3D data acquisition can be realized in the range of field of view of 50° (vertical) × 360° (horizontal). We compensate the refraction of the 3D reconstruction system to reduce the angle error caused by the refraction of light on different media surfaces and reduce the impact of refraction on the image quality. In order to verify the reconstruction effect of the 3D reconstruction system and the effectiveness of the refraction compensation algorithm, we conducted error experiments on a standard sphere. The results show that the system’s underwater reconstruction error is less than 0.6 mm within the working distance of 140 mm~2500 mm, which meets the design requirements. It can provide reference for the development of low-cost underwater 3D laser scanning system.

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Laser Scanning Confocal Microscopy and Three-Dimesnsional Reconstruction of the Mitotic Spindles of Unequally Dividing Embryonic Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100158376 ◽

1990 ◽

Vol 48 (3) ◽

pp. 166-167

Author(s):

J. Holy ◽

G. Schatten

Keyword(s):

Confocal Microscopy ◽

Mitotic Spindle ◽

Laser Scanning ◽

Three Dimensional ◽

Laser Scanning Confocal Microscopy ◽

Two Dimensions ◽

Embryonic Cells ◽

Mitotic Spindles ◽

Cleavage Division ◽

Scanning Confocal Microscopy

One of the classic limitations of light microscopy has been the fact that three dimensional biological events could only be visualized in two dimensions. Recently, this shortcoming has been overcome by combining the technologies of laser scanning confocal microscopy (LSCM) and computer processing of microscopical data by volume rendering methods. We have employed these techniques to examine morphogenetic events characterizing early development of sea urchin embryos. Specifically, the fourth cleavage division was examined because it is at this point that the first morphological signs of cell differentiation appear, manifested in the production of macromeres and micromeres by unequally dividing vegetal blastomeres.The mitotic spindle within vegetal blastomeres undergoing unequal cleavage are highly polarized and develop specialized, flattened asters toward the micromere pole. In order to reconstruct the three-dimensional features of these spindles, both isolated spindles and intact, extracted embryos were fluorescently labeled with antibodies directed against either centrosomes or tubulin.

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Automated 3-D cell population analysis in thick tissue sections using laser-scanning confocal-microscopy data

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100148642 ◽

1993 ◽

Vol 51 ◽

pp. 562-563

Author(s):

Hakan Ancin

Keyword(s):

Laser Scanning ◽

Population Analysis ◽

Three Dimensional ◽

Large Data ◽

Laser Scanning Confocal Microscopy ◽

Tissue Slices ◽

Scanning Confocal Microscopy ◽

Tissue Sections ◽

Spatially Adaptive ◽

Microscopy Data

This paper presents methods for performing detailed quantitative automated three dimensional (3-D) analysis of cell populations in thick tissue sections while preserving the relative 3-D locations of cells. Specifically, the method disambiguates overlapping clusters of cells, and accurately measures the volume, 3-D location, and shape parameters for each cell. Finally, the entire population of cells is analyzed to detect patterns and groupings with respect to various combinations of cell properties. All of the above is accomplished with zero subjective bias.In this method, a laser-scanning confocal light microscope (LSCM) is used to collect optical sections through the entire thickness (100 - 500μm) of fluorescently-labelled tissue slices. The acquired stack of optical slices is first subjected to axial deblurring using the expectation maximization (EM) algorithm. The resulting isotropic 3-D image is segmented using a spatially-adaptive Poisson based image segmentation algorithm with region-dependent smoothing parameters. Extracting the voxels that were labelled as "foreground" into an active voxel data structure results in a large data reduction.

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Measurement of erosion state and refractory lining thickness of blast furnace hearth by using three-dimensional laser scanning method

Metallurgical Research & Technology ◽

10.1051/metal/2020085 ◽

2020 ◽

Vol 118 (1) ◽

pp. 106

Author(s):

Lei Zhang ◽

Jianliang Zhang ◽

Kexin Jiao ◽

Guoli Jia ◽

Jian Gong ◽

...

Keyword(s):

Blast Furnace ◽

Laser Scanning ◽

Refractory Lining ◽

Three Dimensional ◽

3D Laser Scanning ◽

Scanning Method ◽

Blast Furnace Production ◽

Severe Erosion ◽

Residual Thickness ◽

Minimum Depth

The three-dimensional (3D) model of erosion state of blast furnace (BF) hearth was obtained by using 3D laser scanning method. The thickness of refractory lining can be measured anywhere and the erosion curves were extracted both in the circumferential and height directions to analyze the erosion characteristics. The results show that the most eroded positions located below 20# tuyere with an elevation of 7700 mm and below 24#–25# tuyere with an elevation of 8100 mm, the residual thickness here is only 295 mm. In the circumferential directions, the serious eroded areas located between every two tapholes while the taphole areas were protected well by the bonding material. In the height directions, the severe erosion areas located between the elevation of 7600 mm to 8200 mm. According to the calculation, the minimum depth to ensure the deadman floats in the hearth is 2581 mm, corresponding to the elevation of 7619 mm. It can be considered that during the blast furnace production process, the deadman has been sinking to the bottom of BF hearth and the erosion areas gradually formed at the root of deadman.

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