Due to the continuous increase in the volume of spatially located information, the current requirements imposed on the Spatial Information System (SIS) concern increasing data mining capabilities. Modern measurement s...
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Due to the continuous increase in the volume of spatially located information, the current requirements imposed on the Spatial Information System (SIS) concern increasing data mining capabilities. Modern measurement systems, based on devices which enable the automatic recording of observation results on a mass scale (LiDAR-Light Detection and Ranging, MBES-Multi Beam Echo Sounder, etc.), allow for a very large volume of information on the surface to be measured and acquired in a relatively short time. One of the methods to reduce the volume of data enabling the generation of a model surface is to convert unevenly distributed measurement points into a regular network of squares (GRID). However, the generation of a complete grid is not always possible. In the measurement spectrum, there may be areas where measurement points have not been recorded. Measurement points can also be eliminated by either filtering the erroneously recorded data or eliminating the measured vegetation or the utilities in the area. To address these problems, the current article proposes a method for complementing the missing internal nodes in a regular network of squares using polynomial interpolation algorithms. Moreover, the paper demonstrates the possibilities of using the presented method for adding additional points between the already existing nodes of the network of squares. The application of the methodology presented in this article enables the effective elimination of (or a reduction in) the gaps in the GRID structure, which, in turn, allows such a network of squares to be used to generate a more accurate Digital Terrain Model.
With the continuous optimization of methods for acquiring high-resolution and high-precision elevation data, the efficiency of traditional manual contouring plotting has become increasingly difficult to satisfy the ra...
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ISBN:
(纸本)9798400709777
With the continuous optimization of methods for acquiring high-resolution and high-precision elevation data, the efficiency of traditional manual contouring plotting has become increasingly difficult to satisfy the rapid growth of practical demands. Automatic contouring technology, leveraging its ability to automatically generate contour lines from discrete point elevation data, has significantly reduced labor and resource costs while ensuring consistent results. This has led to its widespread application in terrain analysis. The capability of current general algorithms and software to capture subtle geomorphological features when dealing with the complexity of inland water terrains remains limited. This paper reviews some of the mainstream algorithms in automatic contouring, including interpolation methods based on regular grids and irregular triangular meshes, as well as line-tracing methods. Additionally, it elucidates several major automatic contouring software systems, such as the EPS software system developed by Tsinghua Shanwei Company and the ArcGIS platform, and emphasizes the application prospects of hybrid programming techniques combining VC++ and MATLAB in this field. Future research should focus on developing specialized contouring algorithms tailored for the unique geomorphology of inland water areas, designing integrated and efficient hybrid algorithm systems, and developing professional integrated software. Automation technologies should be incorporated throughout the entire mapping workflow to further enhance the accuracy and applicability of inland water contouring.
The uniaxial absolute stress in steel members is a vital indicator for evaluating the performance of steel struc-tures. Non-destructive ultrasonic detection is widely applied in the absolute stress measurement of stee...
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The uniaxial absolute stress in steel members is a vital indicator for evaluating the performance of steel struc-tures. Non-destructive ultrasonic detection is widely applied in the absolute stress measurement of steel members with the advantages of easy implementation, no limits on materials and high precision. The acquisition algorithm of time-of-flight (TOF), the sampling rate of ultrasonic signal and the processing of outliers determine the ac-curacy of the stress measurement. In this study, we proposed a norm and interpolation based algorithm for absolute stress measurement using the longitudinal critically refracted (Lcr) waves, which improves the accuracy and velocity of the absolute stress measurement. Firstly, the norm was designed to obtain the TOF of the ul-trasonic signal. When only the Lcr wave arose in the ultrasonic signal, the two-norm similarity algorithm was found to be consistent with the cross-correlation-based algorithm and the corresponding theoretical expressions were derived. With the non-Lcr wave in the ultrasonic echo, the two-norm similarity algorithm has stronger anti-interference ability. Secondly, the pchipslopes, spline and linear interpolation algorithms were introduced via which the TOF of ultrasound with low sampling rate reaches the same accuracy as that of high sampling rate signal. Finally, a special class of outliers in TOF was explored, and a threshold based on the number of shift points and the stress feature was proposed to calibrate these outliers to normal values. Experiments demonstrate the proposed algorithm improves the accuracy and velocity of uniaxial absolute stress measurement in structural steel members.
Capabilities of some algorithms of interpolation of quadrature signals currently used for creating parallel-type interface modules for high-resolution encoders of linear and angular displacements are analyzed.
Capabilities of some algorithms of interpolation of quadrature signals currently used for creating parallel-type interface modules for high-resolution encoders of linear and angular displacements are analyzed.
Most current digital imaging technologies are based on Bayer color filter array and interpolation algorithms to achieve color image restoration. Common interpolation algorithms include bilinear interpolation algorithm...
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ISBN:
(数字)9781510651890
ISBN:
(纸本)9781510651890;9781510651883
Most current digital imaging technologies are based on Bayer color filter array and interpolation algorithms to achieve color image restoration. Common interpolation algorithms include bilinear interpolation algorithm, edge-directed image interpolation algorithm, and so on. Hibbard algorithm, a kind of edge-directed image interpolation algorithm, significantly improves zipper effect and blurred edges through a gradient-based method and constant chromatic aberration ideas compared with the bilinear interpolation algorithm. However, it only considers the possibility of horizontal and vertical edges, ignoring further judgement for edges in other directions. For solving the severe problems, we propose an oblique interpolation algorithm with the addition of oblique direction gradient factors. In this way, we consider the edges in both main diagonal and sub-diagonal directions. The adjacent pixel information in these directions is used to restore the red and blue channels. The experimental results show that images reconstructed by our algorithm are closer to original images. The reconstructed images have a certain improvement on the sharpness and coherence of oblique edges and arc edges. And the problem of false color in edges with an obvious color difference on both sides is weakened.
Under shear and non-uniform loads, the deformation of the section shape of a casing results in an irregular section, and the spatial continuity is poor. The change in the distance between the wall of the casing before...
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Under shear and non-uniform loads, the deformation of the section shape of a casing results in an irregular section, and the spatial continuity is poor. The change in the distance between the wall of the casing before and after stress is recorded to analyze the deformation of the casing, and the distance value is taken as the key characteristic of the casing. A large number of the key characteristic values of shale gas casing deformation can be obtained by using the circular traversal detection method. At the same time, this article focuses on the center deviation between the laser sensor axis and the pipe string axis, as well as on the disturbance problem during measurement. An eccentricity error correction algorithm is derived to correct the eccentricity error that occurs during the detection process, and then we use interpolation algorithms to draw cubic spline curves to improve detection accuracy. The test results show that the algorithm can effectively eliminate eccentricity errors in measurement and achieve the accurate measurement of deformation casing characteristic values, which can provide basic data for the study of a shale gas casing deformation mechanism.
作者：
Xu, TianzhuoYu, MinghaoLanzhou Univ
Sch Informat Sci & Engn Lanzhou 730107 Gansu Peoples R China Jilin Univ
Sch Software Engn Zhuhai Coll Nanning 530000 Guangxi Peoples R China
Traditional digital cameras use a Bayer array and image interpolation approach to restore a full-colour image. But there is only one-color sampling on each pixel, and the restoration of other colours on each pixel nee...
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ISBN:
(数字)9781510651890
ISBN:
(纸本)9781510651890;9781510651883
Traditional digital cameras use a Bayer array and image interpolation approach to restore a full-colour image. But there is only one-color sampling on each pixel, and the restoration of other colours on each pixel needs to be achieved through the CFA interpolation algorithms. Most algorithms have some distortions, including Zipper Effect, moire, false color, etc. For solving the problems, we proposed a novel algorithm for color image interpolation. This algorithm is based on the Hibbard algorithm and is leveraged for edge judgement. Furthermore, the algorithm involves two successive steps. The first step is to determine the direction of the edge by judging the difference in each direction. In contrast, the second step uses subsequent processing methods to improve the recovery effect of pictures. Experimental results show that compared with the Hibbard algorithm, the algorithm we proposed in this paper performs better under multiple indicators on image processing tasks.
Gully erosion is a worldwide problem of land degradation and water quality,and it is also frequent in ***,anthropic influence is the major driver of gully *** study and monitor gullies it is necessary to use specific ...
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Gully erosion is a worldwide problem of land degradation and water quality,and it is also frequent in ***,anthropic influence is the major driver of gully *** study and monitor gullies it is necessary to use specific instruments and methods to obtain accurate *** objective of this study was to use Terrestrial Laser Scanning(TLS) to create digital elevation model(DEM) accurately and define morphometric variables that characterize gullies in a mountainous *** different interpolations were evaluated using the Topogrid and GridSurfaceCreate algorithms to elaborate *** profile for gullies was used to assess modeling *** DEM of the Gully 1(G1) from the Topogrid algorithm estimated soil loss of 49%,whereas the GridSurfaceCreate algorithm estimated a soil loss of97%,in a period of 1 *** estimated soil loss for the Gully 2(G2) was 14% from the Topogrid,and 8%from the GridSurfaceCreate *** GridSurfaceCreate algorithm underestimated the volume to area ratio for G2 due to a failure on interpolating a region of low point *** Topogrid algorithm represented better the terrain irregularities,as observed through the topographic profiles traced in three regions of G1 and *** analysis showed that the GridSurfaceCreate algorithm presented lower accuracy in estimating *** underestimation trend of this algorithm was also observed in *** gullies showed considerable soil losses,which may reduce the areas suitable for agricultural activities,and silting up of water *** Topogrid algorithm presented satisfactory results,denoting great potential to produce morphometric data of gullies.
Tomographic images generated by wave propagation are important in tree inspections and can be performed in an economically more accessible way using conventional equipment and postprocessed images, but improvements ar...
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Tomographic images generated by wave propagation are important in tree inspections and can be performed in an economically more accessible way using conventional equipment and postprocessed images, but improvements are necessary to increase image quality, giving greater reliability to the results. The objective of this paper was to present a methodological proposal for the definition of parameters related to image quality produced with tomography using ultrasound equipment and postprocessed images. As a case study, the methodology was applied to five trees of the species Cenostigma pluviosum DC. Gagnon & GP Lewis (Sibipiruna). A total of 1512 tomographic images were constructed from five trees to evaluate the cutting velocity, the interpolation algorithms and the filter application. The photographs of the discs were used to evaluate the theoretical wave propagation routes in the measurement grid and to compare the tomographic images using confusion matrix metrics. The application of the methodology proposed in this species allowed us to conclude that the most appropriate velocity range for cavities inference was up to 40% Vmax and for cavities supplemented with biodeterioration up to 45% Vmax;the best interpolator was the Ellipses method with compensation, with the use of a filter;and the accuracy was the most appropriate metric for evaluating image quality.
Orthogonal frequency division multiplexing (OFDM) is a kind of highly transmission technology. It has been taken more and more attention in many ways. In this paper it mainly discussed the simulation process and sever...
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ISBN:
(纸本)9783037856949
Orthogonal frequency division multiplexing (OFDM) is a kind of highly transmission technology. It has been taken more and more attention in many ways. In this paper it mainly discussed the simulation process and several interpolation algorithms in OFDM system. Using computer we simulate the interpolation algorithms in OFDM channel estimation. Through the simulation results we compare the advantage and disadvantage of the interpolation algorithms. At last we can use the conclusion to choose the correct interpolation algorithms in OFDM channel estimation.
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