Single station location method in NLOS environment: The circle fitting algorithm

2010 ◽  
Vol 54 (2) ◽  
pp. 381-385 ◽  
Author(s):  
TianChi Yang ◽  
Liang Jin
Keyword(s):  
Circle Fitting ◽  
Location Method ◽  
Single Station ◽  
Fitting Algorithm ◽  
Station Location

A probabilistic framework for single-station location of seismicity on Earth and Mars

2017 ◽  
Vol 262 ◽  
pp. 48-65 ◽  
Author(s):  
M. Böse ◽  
J.F. Clinton ◽  
S. Ceylan ◽  
F. Euchner ◽  
M. van Driel ◽  
...  
Keyword(s):  
Probabilistic Framework ◽  
Single Station ◽  
Station Location

scholarly journals Relative source location using coda-wave interferometry: Method, code package, and application to mining-induced earthquakes

Geophysics ◽  
2019 ◽  
Vol 84 (3) ◽  
pp. F73-F84 ◽  
Author(s):  
Youqian Zhao ◽  
Andrew Curtis
Keyword(s):  
Single Channel ◽  
Source Region ◽  
Source Location ◽  
Coda Wave ◽  
Data Set ◽  
Seismic Stations ◽  
Location Method ◽  
Wide Range ◽  
Single Station ◽  
Coda Wave Interferometry

A wide range of applications requires the relative locations of sources of energy to be known accurately. Most conventional location methods are either subject to errors that depend strongly on inaccuracy in the model of propagation velocity used or demand a well-distributed network of surrounding seismic stations to produce reliable results. A new source location method based on coda-wave interferometry (CWI) is relatively insensitive to the number of seismic stations and to the source-to-station azimuthal coverage. Therefore, it opens new avenues for research, for applications in areas with unfavorable recording geometries, and for applications that require a complementary method. This method uses CWI to estimate distances between pairs of seismic events with a similar source mechanism recorded at the same station. These separation estimates are used to solve for the locations of clusters of events relative to one another within a probabilistic framework through optimization. It is even possible to find the relative locations of clusters of events with one single-channel station. Given these advantages, it is likely that one reason that the method is not used more widely is the lack of reliable code that implements this multistage method. Therefore, we have developed a well-commented MATLAB code that does so, and we evaluate examples of its applications. It can be used with seismic data from a single-station channel, and it enables data recorded by different channels and stations to be used simultaneously. It is therefore possible to combine data from permanent yet sparse networks and from temporary arrays closer to the source region. We use the code to apply the location method to a selected data set of the New Ollerton earthquakes in England to demonstrate the validity of the code. The worked example is provided within the package. A way to assess the quality of the location results is also provided.

scholarly journals A High Precision Laser-Based Autofocus Method Using Biased Image Plane for Microscopy

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Chao-Chen Gu ◽  
Hao Cheng ◽  
Kai-Jie Wu ◽  
Liang-Jun Zhang ◽  
Xin-Ping Guan
Keyword(s):  
Laser Beam ◽  
High Precision ◽  
Low Cost ◽  
Image Plane ◽  
Circle Fitting ◽  
Essential Factor ◽  
Assembly Accuracy ◽  
Fitting Algorithm ◽  
Experiment Device ◽  
Study Designs

This study designs and accomplishes a high precision and robust laser-based autofocusing system, in which a biased image plane is applied. In accordance to the designed optics, a cluster-based circle fitting algorithm is proposed to calculate the radius of the detecting spot from the reflected laser beam as an essential factor to obtain the defocus value. The experiment conduct on the experiment device achieved novel performance of high precision and robustness. Furthermore, the low demand of assembly accuracy makes the proposed method a low-cost and realizable solution for autofocusing technique.

scholarly journals Waveforms clustering and single-station location of microearthquake multiplets recorded in the northern Sicilian offshore region

2013 ◽  
Vol 194 (3) ◽  
pp. 1789-1809 ◽  
Author(s):  
Antonino D’Alessandro ◽  
Giorgio Mangano ◽  
Giuseppe D’Anna ◽  
Dario Luzio
Keyword(s):  
Single Station ◽  
Station Location ◽  
Offshore Region

Automatic Calibration Method for Mounting Position of Protein Crystal Mounting Robot Based on Visual Positioning

2020 ◽  
Author(s):  
Jiangping Qin ◽  
Zhaolong Li ◽  
Bo Sun ◽  
Feng Yu ◽  
Yi Liu ◽  
...  
Keyword(s):  
Calibration Method ◽  
Image Features ◽  
Protein Crystal ◽  
External Parameter ◽  
Automatic Calibration ◽  
Relationship Matrix ◽  
Laser Sensor ◽  
Circle Fitting ◽  
Visual Positioning ◽  
Fitting Algorithm

Abstract With the popularization of automounting robots in protein crystal diffraction experiment beamline stations, the coordinate calibration of the robot sample mounting position has become an inevitable task in the daily maintenance of the beamline station. In this method, the image features of the laser sensor spot and goniometer are extracted by color extraction and edge detection, respectively, and the noise is eliminated by median filtering. Then, after locating the pixel coordinates of the center of the circle through the Hough circle detection and the minimum closed circle fitting algorithm, the coordinates in the base coordinate system are obtained using the camera internal and external parameter matrices and the hand-eye relationship matrix. Finally, according to the deviation of the laser spot and the visual positioning coordinate of the goniometer, the position of the robot is compensated to improve the positioning accuracy, and the automatic calibration of the sample point is realized.

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