scholarly journals Determination of Radial Segmentation of Point Clouds Using K-D Trees with the Algorithm Rejecting Subtrees

Symmetry ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1451 ◽  
Author(s):  
Jerzy Orlof ◽  
Paweł Ozimek ◽  
Piotr Łabędź ◽  
Adrian Widłak ◽  
Mateusz Nytko
Keyword(s):  
Computer Graphic ◽  
Point Clouds ◽  
Binary Trees ◽  
Graphic Method ◽  
Triangulated Irregular Network ◽  
Mathematical Algorithm

This paper presents an innovative computer graphic method for viewshed generation from big point clouds. The proposed approach consists in simplification of typical methods for viewshed formation that are based on sorting and binary trees. The proposed method is based on the k-d tree concept optimized with radial segmentation and a dedicated mathematical algorithm for subtree rejection. The final visualization of the viewshed is designed with a graphic method using triangulated irregular network (TIN) surfaces from the accepted subtrees.

Accuracy Analysis of Fringe Projection Systems Based on Blue Light Technology

2014 ◽  
Vol 615 ◽  
pp. 9-14 ◽  
Author(s):  
Claudio Bernal ◽  
Beatriz de Agustina ◽  
Marta María Marín ◽  
Ana Maria Camacho
Keyword(s):  
Blue Light ◽  
Point Clouds ◽  
Fringe Projection ◽  
Accuracy Analysis ◽  
Scanning Procedure ◽  
Structured Light Scanner ◽  
Cloud Of Points ◽  
3D Digitizing

Some manufacturers of 3D digitizing systems are developing and market more accurate, fastest and affordable systems of fringe projection based on blue light technology. The aim of the present work is the determination of the quality and accuracy of the data provided by the LED structured light scanner Comet L3D (Steinbichler). The quality and accuracy of the cloud of points produced by the scanner is determined by measuring a number of gauge blocks of different sizes. The accuracy range of the scanner has been established through multiple digitizations showing the dependence on different factors such as the characteristics of the object and scanning procedure. Although many factors influence, accuracies announced by manufacturer have been achieved under optimal conditions and it has been noted that the quality of the point clouds (density, noise, dispersion of points) provided by this system is higher than that obtained with laser technology devices.

scholarly journals Simple estimation of granule size distribution and sludge bed porosity in a UASB reactor

2013 ◽  
Vol 10 (1) ◽  
pp. 73-79
Keyword(s):  
Size Distribution ◽  
Granular Sludge ◽  
Granule Size ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Reactor Performance ◽  
Efficient Operation ◽  
Mathematical Algorithm ◽  
Bed Porosity

Granular sludge is the key factor for an efficient operation of an upflow anaerobic sludge blanket (UASB) reactor. In order to monitor the granularity of anaerobic sludge, the determination of the granule size distribution is of vital importance. Another critical parameter for the UASB reactor performance is the sludge bed porosity. For this reason, several techniques have been proposed, however they are either tedious, imprecise or expensive and hardly applicable in full scale treatment plants. There was then the need for a simple and low cost technique. This technique involves the determination of the settling velocities of a sludge sample and of extrapolating the corresponding diameters using a mathematical algorithm. In the proposed algorithm, the granules density was calculated, the flow regime was examined and finally the granule size distribution was obtained. Some very important correlations were suggested by the experimental results. The granule density and diameter as well as the sludge bed porosity were strongly correlated with the VSS/TSS ratio.

scholarly journals Use of geotechnologies in mining planning in Quarries carbonated rocks - Contribution to the digital transition (Industry 4.0)

2021 ◽  
Vol 906 (1) ◽  
pp. 012015
Author(s):  
João Duarte ◽  
Francisco Sousa ◽  
Bruno Valente
Keyword(s):  
Industry 4.0 ◽  
Economic Valuation ◽  
Reference Value ◽  
Point Clouds ◽  
Detection Algorithm ◽  
Second Phase ◽  
Ornamental Stone ◽  
Use Of Resources ◽  
Photogrammetric Method

Abstract As part of the strategy for Industry 4.0, this work was developed to outline a methodology that is an important contribution to improve the efficiency and productivity of processes in the ornamental stone extraction industry. Since this sector is important for the Portuguese economy, it is imperative to optimize processes to improve their efficiency in the use of resources, economic valuation, and economic viability. Knowing that one of the main factors to take into account in the feasibility of an exploration of ornamental rocks is the density, persistence and attitude of the discontinuities present in the rock mass, a methodology is proposed that aims to map and characterize the existing discontinuities in the using the latest digital technologies and whenever possible open access (CloudCompare, Stereonet, 3D Block Expert). To this end, work was initially carried out on an active exploration front, identifying and characterizing, through the traditional method (compass and clinometer) and photogrammetry, existing discontinuities and statistically analysing their occurrence. The data analysis shows a variation in the attitude of the discontinuities in a range of -17.72 ° to 14.7 °, this variation corresponding to the strike. As a percentage, there is also a variation in the range of values, from -5.30% to 4.91%, with the reference value being the value obtained by the photogrammetric method. This step was also used to compare the acquired data and verify the variations between them depending on the method used. Photogrammetry was used with another complementary purpose, but very important for the proposed methodology, which is related to the 3D modelling of the fronts and the subsequent projection or extraction of the existing discontinuity plans. The determination of the attitude of the discontinuities was obtained through the manipulation of the point clouds obtained by the photogrammetric modelling, based on the technique of Structure for Motion [SfM] and application of the RANSAC Shape Detection algorithm of the CloudCompare® program, which allows the determination of the attitude of the discontinuities. The characterization of the discontinuities by the photogrammetric method provided the data that was used in the present study to calculate the blocometry in that sector. This was calculated using the 3D BlockExpert software, based on the exploration sequences. The program calculated the predicted volumes in each one, based on a standard dimension for the block of 2.7 × 3.0 × 2.0 meters. As a result, it was possible to compare a number of blocks the value predicted by the 449 modellings and the number of blocks produced 490. This difference of approximately 10% for this order of magnitude is acceptable and confirms the reliability of the proposed methodology. This evaluation using Geotechnologies allows data modelling to be effectively an important process in the planning of the extractive process, and with the development of this approach, it may introduce in a second phase the decision automation of the extractive process, based on economic and commercial criteria and last and third stage, the automation of the extractive process.

Graphic method for the determination of titration end-points

Talanta ◽  
1966 ◽  
Vol 13 (10) ◽  
pp. 1431-1442 ◽  
Author(s):  
Folke Ingman ◽  
Ebbe Still
Keyword(s):  
Graphic Method ◽  
End Points

scholarly journals Low-Frequency Magnetic Scanning Device and Algorithm for Determining the Magnetic and Non-Magnetic Fractions of Moving Metallurgical Raw Materials

2019 ◽  
Vol 9 (10) ◽  
pp. 2001
Author(s):  
Vladimir Kochemirovsky ◽  
Svetlanav Kochemirovskaia ◽  
Michael Malygin ◽  
Alexey Kuzmin ◽  
Maxim Novomlinsky ◽  
...  
Keyword(s):  
Mass Fraction ◽  
Raw Materials ◽  
Low Frequency ◽  
Raw Material ◽  
Magnetic Characteristics ◽  
Magnetic Fraction ◽  
Measuring Device ◽  
Mathematical Algorithm ◽  
Macroscopic Objects

The development of an algorithm to automate the process of measuring the magnetic properties of macroscopic objects in motion is an important problem in various industries, especially in ferrous metallurgy and at factories where ferrous scrap is a strategic raw material. The parameter that requires work control is the hidden mass fraction of a non-magnetic substance that is present in the ferromagnetic raw material. The solution to this problem has no prototypes. In our work, a simple measuring device and a mathematical algorithm for calculating the mass fraction of the non-magnetic fraction in a strongly magnetic matrix were developed. The device is an inductance coil, in which the angle of the electromagnet losses is related to the mass of the magnetic material moving the coil. The magnitude of the instantaneous values of the lost angle integral was compared with the result of weighing the object on scales. This allowed us to calculate the proportion of the magnetic and non-magnetic fractions. The use of this prototype is herein illustrated. The experimental results of the determination of the magnetic-fractional composition depending on the mass of scrap metal and its bulk and the magnetic characteristics are presented.

scholarly journals TLS and SfM Approach for Bulk Density Determination of Excavated Heterogeneous Raw Materials

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 174 ◽  
Author(s):  
Peter Blistan ◽  
Stanislav Jacko ◽  
Ľudovít Kovanič ◽  
Julián Kondela ◽  
Katarína Pukanská ◽  
...  
Keyword(s):  
Bulk Density ◽  
Laser Scanning ◽  
Large Scale ◽  
Raw Materials ◽  
Terrestrial Laser Scanning ◽  
Mineral Resources ◽  
Point Clouds ◽  
Raw Material

A frequently recurring problem in the extraction of mineral resources (especially heterogeneous mineral resources) is the rapid operative determination of the extracted quantity of raw material in a surface quarry. This paper deals with testing and analyzing the possibility of using unconventional methods such as digital close-range photogrammetry and terrestrial laser scanning in the process of determining the bulk density of raw material under in situ conditions. A model example of a heterogeneous deposit is the perlite deposit Lehôtka pod Brehmi (Slovakia). Classical laboratory methods for determining bulk density were used to verify the results of the in situ method of bulk density determination. Two large-scale samples (probes) with an approximate volume of 7 m3 and 9 m3 were realized in situ. 6 point samples (LITH) were taken for laboratory determination. By terrestrial laser scanning (TLS) measurement from 2 scanning stations, point clouds with approximately 163,000/143,000 points were obtained for each probe. For Structure-from-Motion (SfM) photogrammetry, 49/55 images were acquired for both probes, with final point clouds containing approximately 155,000/141,000 points. Subsequently, the bulk densities of the bulk samples were determined by the calculation from in situ measurements by TLS and SfM photogrammetry. Comparison of results of the field in situ measurements (1841 kg∙m−3) and laboratory measurements (1756 kg∙m−3) showed only a 4.5% difference in results between the two methods for determining the density of heterogeneous raw materials, confirming the accuracy of the used in situ methods. For the determination of the loosening coefficient, the material from both large-scale samples was transferred on a horizontal surface. Their volumes were determined by TLS. The loosening coefficient for the raw material of 1.38 was calculated from the resulting values.

scholarly journals Assessing the effect of wind farms in fauna with a mathematical model

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Pablo Refoyo Román ◽  
Cristina Olmedo Salinas ◽  
Benito Muñoz Araújo
Keyword(s):  
Mathematical Model ◽  
Renewable Energy ◽  
Wind Turbines ◽  
Energy Production ◽  
Wind Farm ◽  
Considerable Increase ◽  
Wind Farms ◽  
Mathematical Algorithm ◽  
The World

Abstract Energy production by wind turbines has many advantages. The wind is a renewable energy that does not emit greenhouse gases and has caused a considerable increase in wind farms around the world. However, this type of energy is not completely free of impact. In particular, wind turbines displace and kill a wide variety of wild species what forces us to plan their location well. In any case, the determination of the effects of wind farms on fauna, especially the flying one, is difficult to determine and depends on several factors. In this work, we will try to establish a mathematical algorithm that allows us to combine all variables that affect the species with the idea of quantifying the effect that can cause the installation of a wind farm with certain characteristics in a given place. We have considered specific parameters of wind farms, the most relevant environmental characteristics related to the location of the wind farm, and morphological, ethological and legal characteristics in the species. Two types of assessment are established for the definitive valuation. Total Assessment and Weighted Assessment. Total Valuation is established based on a reference scale that will allow us to establish categories of affection for the different species while Weighted valuation allows us to establish which species are most affected.

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