scholarly journals Combined DEM Extration Method from StereoSAR and InSAR

2015 ◽  
Vol XL-7/W4 ◽  
pp. 231-234
Author(s):  
Z. Zhao ◽  
J. X. Zhang ◽  
M. Y. Duan ◽  
G. M. Huang ◽  
S. C. Yang
Keyword(s):  
Geometric Model ◽  
Three Dimensional ◽  
Phase Model ◽  
Stereo Image ◽  
Sar Images ◽  
Phase Equation ◽  
Image Coregistration ◽  
Adjustment Model ◽  
Image Pairs ◽  
Range Equation

A pair of SAR images acquired from different positions can be used to generate digital elevation model (DEM). Two techniques exploiting this characteristic have been introduced: stereo SAR and interferometric SAR. They permit to recover the third dimension (topography) and, at the same time, to identify the absolute position (geolocation) of pixels included in the imaged area, thus allowing the generation of DEMs. In this paper, StereoSAR and InSAR combined adjustment model are constructed, and unify DEM extraction from InSAR and StereoSAR into the same coordinate system, and then improve three dimensional positioning accuracy of the target. We assume that there are four images 1, 2, 3 and 4. One pair of SAR images 1,2 meet the required conditions for InSAR technology, while the other pair of SAR images 3,4 can form stereo image pairs. The phase model is based on InSAR rigorous imaging geometric model. The master image 1 and the slave image 2 will be used in InSAR processing, but the slave image 2 is only used in the course of establishment, and the pixels of the slave image 2 are relevant to the corresponding pixels of the master image 1 through image coregistration coefficient, and it calculates the corresponding phase. It doesn’t require the slave image in the construction of the phase model. In Range-Doppler (RD) model, the range equation and Doppler equation are a function of target geolocation, while in the phase equation, the phase is also a function of target geolocation. We exploit combined adjustment model to deviation of target geolocation, thus the problem of target solution is changed to solve three unkonwns through seven equations. The model was tested for DEM extraction under spaceborne InSAR and StereoSAR data and compared with InSAR and StereoSAR methods respectively. The results showed that the model delivered a better performance on experimental imagery and can be used for DEM extraction applications.

scholarly journals Three-Dimensional Glacier Changes in Geladandong Peak Region in the Central Tibetan Plateau

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1749 ◽  
Author(s):  
Junli Xu ◽  
Donghui Shangguan ◽  
Jian Wang
Keyword(s):  
Three Dimensional ◽  
Stereo Image ◽  
Surface Elevation ◽  
Glacier Area ◽  
Glacier Surface ◽  
Contour Lines ◽  
The Status ◽  
Glacier Length ◽  
Image Pairs ◽  
Increasing Temperature

In this study, contour lines from the topographic maps at a 1:100,000 scale (mapped in 1968), Landsat MSS/TM/OLI images, ASTER images and SPOT 6-7 stereo image pairs were used to study changes in glacier length, area and surface elevation. We summarized the results using the following three conclusions: (1) During the period from 1973 to 2013, glaciers retreated by 412 ± 32 m at a mean retraction rate of 10.3 ± 0.8 m·year−1 and the relative retreat was 5.6 ± 0.4%. The glacier area shrank by 7.5 ± 3.4%, which was larger than the glacier length. In the periods of 1968–2000, 2000–2005 and 2000–2013, the glacier surface elevation change rates were −7.7 ± 1.4 m (−0.24 ± 0.04 m·year−1), −1.9 ± 1.5 m (−0.38 ± 0.25 m·year−1) and −5.0 ± 1.4 m (−0.38 ± 0.11 m·year−1), respectively. The changes in the glacier area and thickness exhibited similar trends, both showing a significant increasing reduction after 2000. (2) Eleven glaciers were identified as surging glaciers. Changes of the mass balance in surging glaciers were stronger than in non-surging glaciers between 1968 and 2013. Changes of area in surging glaciers were weaker than in non-surging glaciers. (3) Increasing temperature was the major cause of glacier thickness reduction and area shrinkage. The increase in precipitation, to a certain extent, inhibited glacial ablation but it did not change the status of the shrinkage in the glacial area and the reduction in the glacier thickness.

The Optical Wonder of the Age

2014 ◽  
pp. 1-12
Author(s):  
Roger Taylor
Keyword(s):  
Three Dimensional ◽  
Historical Background ◽  
Stereo Image ◽  
Railway Network ◽  
Photographic Images ◽  
Auction Houses ◽  
Heated Debate ◽  
Image Pairs ◽  
Public Reaction ◽  
First Time

The birth of three-dimensional photography was highly controversial with much heated debate and rivalry from its proponents who competed to be first. This chapter highlights the historical background of 3-D by quoting The Great Exhibition of 1850 and the birth of commercial stereoscopic photography. For the first time audiences were introduced to Brewster's stereoscope, allied to Daguerre's photographic images and so successful was public reaction that by 1852 the system had become a commercial triumph with much to be gained. During the following decade the new steam railway network rapidly engulfed much of the British Isles and Europe, making the distribution of mass replicated stereo-views within easy reach for many. Indeed entrepreneurs, such as John Nottage, commissioned sets of stereo-views and built a catalogue of more than 10,000 stereo image pairs that are still highly sought after in todays auction houses. Public interest peaked around 1870 and thereafter began to decline, due in part to the stereo photograph, or pair, becoming ubiquitous. Roger Taylor offers a glimpse into that period of history when enthusiasm for the stereo photograph has never been surpassed.

Three-dimensional Reconstruction of Microscopic Image Based on Multi-ST Algorithm

2020 ◽  
Vol 64 (2) ◽  
pp. 20506-1-20506-7
Author(s):  
Min Zhu ◽  
Rongfu Zhang ◽  
Pei Ma ◽  
Xuedian Zhang ◽  
Qi Guo
Keyword(s):  
3D Reconstruction ◽  
Three Dimensional ◽  
Scale Model ◽  
Microscopic Image ◽  
Multi Scale ◽  
Gaussian Pyramid ◽  
Cost Aggregation ◽  
Dimensional Reconstruction ◽  
Image Pairs ◽  
Accurate Matching

Abstract Three-dimensional (3D) reconstruction is extensively used in microscopic applications. Reducing excessive error points and achieving accurate matching of weak texture regions have been the classical challenges for 3D microscopic vision. A Multi-ST algorithm was proposed to improve matching accuracy. The process is performed in two main stages: scaled microscopic images and regularized cost aggregation. First, microscopic image pairs with different scales were extracted according to the Gaussian pyramid criterion. Second, a novel cost aggregation approach based on the regularized multi-scale model was implemented into all scales to obtain the final cost. To evaluate the performances of the proposed Multi-ST algorithm and compare different algorithms, seven groups of images from the Middlebury dataset and four groups of experimental images obtained by a binocular microscopic system were analyzed. Disparity maps and reconstruction maps generated by the proposed approach contained more information and fewer outliers or artifacts. Furthermore, 3D reconstruction of the plug gauges using the Multi-ST algorithm showed that the error was less than 0.025 mm.

A New Geometric Model of Laid-in Weft-Knitted Fabrics

2021 ◽  
pp. 004051752199276
Author(s):  
Ki Wai Fong ◽  
Si Qing Li ◽  
Rong Liu
Keyword(s):  
Cost Estimation ◽  
Geometric Model ◽  
Three Dimensional ◽  
Wearable Electronics ◽  
Material Consumption ◽  
Knitted Fabrics ◽  
Functional Textiles ◽  
Loop Pattern ◽  
Spatial Configurations ◽  
Consumption Prediction

Inlay yarn and laid-in structures are important technical knitting elements that have been increasingly applied in the structural design of functional textiles in industrial, medical, and wearable electronics fields. However, there is no currently established geometric model to numerically analyze their spatial morphologies and structural properties. This study presents a new geometric model and numerical analysis approach to characterize spatial configurations of inlay yarn and ground yarn in a three-dimensional scenario for laid-in weft-knitted fabrics. Loop lengths of the inlay and ground yarn materials were calculated and analyzed under different contact and deformation conditions to estimate material consumption in this complex interlooping layout. Series of laid-in weft-knitted fabrics made of different combinations of ground and inlay yarns were fabricated with the 1 × 1 laid-in loop pattern and tested for the model validation. The comparisons between the experimental and calculated results indicated that the newly developed geometric model favorably agreed with the experimental measurements regarding the ground loop lengths and inlay loop lengths applied in the laid-in weft-knitted structures. The results indicated the applicability of the developed geometric model of laid-in weft-knitted fabrics with similar structural patterns in practical use. The output of this study provides a theoretical and practical reference for structural and physical properties analysis, material consumption prediction, even cost estimation of laid-in weft-knitted fabrics.

scholarly journals Simulation and Analysis of Floodlighting Based on 3D Computer Graphics

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1042
Author(s):  
Rafał Krupiński
Keyword(s):  
Computer Graphics ◽  
External Surface ◽  
Geometric Model ◽  
Three Dimensional ◽  
Fold Increase ◽  
Luminance Level ◽  
Object Model ◽  
Geometric Mesh ◽  
Average Luminance ◽  
To Receive

The paper presents the opportunities to apply computer graphics in an object floodlighting design process and in an analysis of object illumination. The course of object floodlighting design has been defined based on a virtual three-dimensional geometric model. The problems related to carrying out the analysis of lighting, calculating the average illuminance, luminance levels and determining the illuminated object surface area are also described. These parameters are directly tied with the calculations of the Floodlighting Utilisation Factor, and therefore, with the energy efficiency of the design as well as the aspects of light pollution of the natural environment. The paper shows how high an impact of the geometric model of the object has on the accuracy of photometric calculations. Very often the model contains the components that should not be taken into account in the photometric calculations. The research on what influence the purity of the geometric mesh of the illuminated object has on the obtained results is presented. It shows that the errors can be significant, but it is possible to optimise the 3D object model appropriately in order to receive the precise results. For the example object presented in this paper, removing the planes that do not constitute its external surface has caused a two-fold increase in the average illuminance and average luminance. This is dangerous because a designer who wants to achieve a specific average luminance level in their design without optimizing the model will obtain the luminance values that will actually be much higher.

Analysis of Cluttered Scenes Using an Elastic Matching Approach for Stereo Images

2006 ◽  
Vol 18 (6) ◽  
pp. 1441-1471 ◽  
Author(s):  
Christian Eckes ◽  
Jochen Triesch ◽  
Christoph von der Malsburg
Keyword(s):  
Graph Matching ◽  
Recognition Performance ◽  
Stereo Image ◽  
Matching Algorithm ◽  
Automatic Interpretation ◽  
Color Features ◽  
Occluded Objects ◽  
Elastic Graph Matching ◽  
Image Pairs ◽  
Object Models

We present a system for the automatic interpretation of cluttered scenes containing multiple partly occluded objects in front of unknown, complex backgrounds. The system is based on an extended elastic graph matching algorithm that allows the explicit modeling of partial occlusions. Our approach extends an earlier system in two ways. First, we use elastic graph matching in stereo image pairs to increase matching robustness and disambiguate occlusion relations. Second, we use richer feature descriptions in the object models by integrating shape and texture with color features. We demonstrate that the combination of both extensions substantially increases recognition performance. The system learns about new objects in a simple one-shot learning approach. Despite the lack of statistical information in the object models and the lack of an explicit background model, our system performs surprisingly well for this very difficult task. Our results underscore the advantages of view-based feature constellation representations for difficult object recognition problems.

The Vehicle Dynamical Analysis of a High-Speed Train Passing through a Tunnel

2010 ◽  
Vol 29-32 ◽  
pp. 835-840 ◽  
Author(s):  
Zhi Peng Feng ◽  
Ji Ye Zhang ◽  
Wei Hua Zhang
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Geometric Model ◽  
Three Dimensional ◽  
Grid Method ◽  
Dynamical Analysis ◽  
High Speed Train ◽  
Flow Induced Vibration ◽  
Running Safety ◽  
Dynamics Calculation

As the speed of train increases, flow-induced vibration of trains passing through tunnels has become a subject of discussion, to investigate this phenomenon, a simplified geometric model and a vehicle dynamics model of a high-speed train traveling through a tunnel were built. To analyze the unsteady three-dimensional flow around the train, the 3-D, transient, viscous, compressible Reynolds-averaged Navier-Stokes equations combined with the k- two-equation turbulence model were solved with the finite volume method. The motion of the train was carried out using the technique of sliding grid method. The dynamics response of the train was obtained by means of the computational multi-body dynamics calculation. Meanwhile the running safety and riding comfort of the train were analyzed. With the numerical simulation, the variation of aerodynamic forces was obtained. The research founds that, vibration of the train increases drastically during it passing through a tunnel. The running safety and riding quality of the train are reduced greatly but they are in the safe range.

scholarly journals Estimation of three-dimensional crustal movements in the 2011 Tohoku-oki, Japan earthquake from TerraSAR-X intensity images

2014 ◽  
Vol 2 (12) ◽  
pp. 7383-7408
Author(s):  
W. Liu ◽  
F. Yamazaki ◽  
M. Matsuoka ◽  
T. Nonaka ◽  
T. Sasagawa
Keyword(s):  
Three Dimensional ◽  
Short Time Period ◽  
Sar Images ◽  
Crustal Movements ◽  
Surface Displacements ◽  
Time Period ◽  
Intensity Images ◽  
Short Time ◽  
The Relationship ◽  
Gps Observations

Abstract. The Tohoku-Oki earthquake on 11 March 2011 caused significant widespread crustal movements. In a previous study, we proposed a method for capturing two-dimensional (2-D) surface displacements from a pair of pre- and post-event TerraSAR-X (TSX) intensity images. However, it is difficult to detect three-dimensional (3-D) displacements from one pair of TSX images. In this study, three pairs of pre- and post-event TSX images taken on different paths were used to estimate 3-D crustal movements. The relationship between the actual 3-D displacements and the converted 2-D movements in the SAR images was derived based on the observation model of a SAR sensor. The 3-D movements were then calculated from three sets of detected 2-D movements that occurred within a short time period. Compared with GPS observations, the proposed method was found to be capable of detecting the 3-D crustal movements with sub-pixel accuracy.

A Three-Dimensional Three-Phase Model of Gas Injection in AOD Converters

2013 ◽  
Vol 85 (3) ◽  
pp. 376-387 ◽  
Author(s):  
Anders Tilliander ◽  
Lage T. I. Jonsson ◽  
Pär G. Jönsson
Keyword(s):  
Gas Injection ◽  
Three Dimensional ◽  
Phase Model ◽  
Three Phase
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