Research on Resistivity Measurement System of Submarine Sediment

2013 ◽  
Vol 455 ◽  
pp. 486-490
Author(s):  
Lai Jie Wu ◽  
Bin Ma ◽  
Yuan Hong Yang
Keyword(s):  
Measurement System ◽  
Cross Correlation ◽  
Resistivity Measurement ◽  
Matlab Simulation ◽  
Theoretical Derivation ◽  
Correlation Algorithm ◽  
Improve Accuracy ◽  
Voltage Signal ◽  
The Cross

This paper developed a resistivity measurement system on the platform of in-situ detector which based on seafloor drilling machine. In order to precisely process the weak voltage signal which outputted by the resistivity probe, the paper carried out the cross-correlation algorithm theoretical derivation and MATLAB simulation, then ported the algorithm to TMS320F28069 DSP processor and designed hardware. A mass of contrast experiment shows that the cross-correlation algorithm is an effective method to process weak signal. It can improve accuracy and anti-jamming ability of the submarine sediment resistivity measurement system. The method of submarine sediment resistivity measurement can be widely used in fields of marine geological survey, marine environment research, etc.

Application of Cross-Correlation Algorithm in Submarine Sediment Resistivity Measurement

2013 ◽  
Vol 446-447 ◽  
pp. 1123-1128
Author(s):  
Lai Jie Wu ◽  
Bin Ma ◽  
Qi Chen ◽  
Wei Jiang
Keyword(s):  
Measurement System ◽  
Cross Correlation ◽  
Resistivity Measurement ◽  
Matlab Simulation ◽  
Theoretical Derivation ◽  
Correlation Algorithm ◽  
Improve Accuracy ◽  
Voltage Signal ◽  
The Cross

This paper developed a resistivity measurement system on the platform of in-situ detector which based on seafloor drilling machine. In order to precisely process the weak voltage signal which outputted by the resistivity probe, the paper carried out the cross-correlation algorithm theoretical derivation and MATLAB simulation, then ported the algorithm to TMS320F28069 DSP processor and designed hardware. A mass of contrast experiment shows that the cross-correlation algorithm is an effective method to process weak signal. It can improve accuracy and anti-jamming ability of the submarine sediment resistivity measurement system. The method of submarine sediment resistivity measurement can be widely used in fields of marine geological survey, marine environment research, etc.

Study on Velocity Measurement of Gas/Solid Flow Based on Electrostatic Sensor

2014 ◽  
Vol 614 ◽  
pp. 275-278
Author(s):  
Yu Tang ◽  
Xiang Deng ◽  
Shuo Tian
Keyword(s):  
Measurement System ◽  
Velocity Measurement ◽  
Flow Measurement ◽  
Cross Correlation ◽  
Low Cost ◽  
High Sensitivity ◽  
Two Phase ◽  
Solid Flow ◽  
Correlation Algorithm ◽  
Electrostatic Induction

Electrostatic sensor is based on the principle of electrostatic induction. It is widely used for gas/solid two-phase flow measurement because it has the advantages of simple structure, high sensitivity, low cost, etc. In this paper, a velocity measurement system of gas/solid flow based on electrostatic sensor and cross-correlation algorithm is discussed. Electrostatic sensor with circular electrode is adopted. By COMSOL optimum simulation, the axial length of the electrode is designed. The signal conditioning circuits are discussed and cross-correlation algorithm is analyzed. The initial experimental results demonstrate that the velocity measurement system of gas/solid flow designed in this paper is feasible.

A New Image-Based Soil Deformation Measurement System

2012 ◽  
Vol 629 ◽  
pp. 488-492
Author(s):  
Yan Jiao Zhao ◽  
Yu Xin Wang ◽  
Guo He ◽  
Hong Hua Zhao
Keyword(s):  
Neural Network ◽  
Measurement System ◽  
Cross Correlation ◽  
Particle Image ◽  
Research Field ◽  
Deformation Measurement ◽  
Practical Significance ◽  
Soil Deformation ◽  
Correlation Algorithm ◽  
Image Velocimetry

A Soil Deformation Measurement System using OPENCV library and FFTW library in C++ was developed in this paper. The system applied camera calibration based on neural network and Fasst Fourier Transform (FFT) cross-correlation algorithm for Particle Image Velocimetry (PIV). It is used to obtain soil deformation data, such as displacements, velocity and strain, and visualize the deformation. Experiments show that this system could acquire deformation data from soil images accurately, efficiently and continuously, which provides a strong proof that image processing technology has practical significance and application value in the research field of geotechnical engineering.

Identifying evolving/non-evolving plasma bubbles from SWARM observations

2021 ◽  
Author(s):  
Chinmaya Nayak ◽  
Stephan Buchert ◽  
Bharati Kakad
Keyword(s):  
Electric Field ◽  
Electron Density ◽  
Cross Correlation ◽  
Neutral Atmosphere ◽  
Magnetic Fluctuations ◽  
Equatorial Station ◽  
Plasma Bubbles ◽  
Field Fluctuations ◽  
The Cross

<p>Equatorial plasma bubbles (EPBs) are generally caused due to the Rayleigh–Taylor instability. During the initial phase of the growth of the instability, the bubbles are associated with perturbation electric and magnetic fields. We call this the evolving (active) phase of the EPB. Over time, these electric field fluctuations decay in amplitude and the bubble, embedded in the neutral atmosphere, drifts eastward without much temporal evolution. We call this the non-evolving phase. Both phases can be distinguished in ground based VHF spaced receiver scintillation observations. In the evolving phase, the cross correlation between the signals from the two receivers is significantly less than one because of rapidly evolving perturbation electric fields. However, after some time (~2 hours) as the perturbation electric field decays, the cross correlation reaches almost 1 implying very slow temporal changes. This technique is applied to identify fresh generation of post-midnight plasma bubbles during magnetically disturbed conditions. From in situ satellite observations, the EPBs are generally identified as sudden depletion from background electron density, associated with magnetic fluctuations. In fact, the plasma bubble index produced from data of the ESA Swarm mission utilizes this same criteria of concurrent density depletions and magnetic fluctuations to identify the plasma bubbles. However, it is not so straightforward to distinguish evolving and non-evolving phases of the plasma bubbles in the SWARM plasma and magnetic observations. We look into near simultaneous in situ observations of SWARM and ground based VHF spaced receiver scintillation to identify a standard criteria for distinguishing evolving/non-evolving bubbles in SWARM observations. The results suggest that the presence/absence of magnetic fluctuations associated with the depletion in electron density can be used as a criteria for evolving/non-evolving bubbles. Ideally, the electric and magnetic field fluctuations should be present simultaneously and as a result should decay simultaneously. We have looked into one year (2014) of SWARM observations of EPBs and VHF spaced receiver scintillation data from Indian equatorial station Tirunelveli. A few case studies during both magnetically quiet and disturbed conditions are discussed.</p>

Two-Component Horizontal Aerosol Motion Vectors in the Atmospheric Surface Layer from a Cross-Correlation Algorithm Applied to Scanning Elastic Backscatter Lidar Data*

2012 ◽  
Vol 29 (11) ◽  
pp. 1585-1602 ◽  
Author(s):  
Shane D. Mayor ◽  
Jennifer P. Lowe ◽  
Christopher F. Mauzey
Keyword(s):  
Cross Correlation ◽  
Empirical Relationship ◽  
Sonic Anemometer ◽  
Leading Edge ◽  
Horizontal Wind ◽  
Motion Vectors ◽  
Correlation Algorithm ◽  
Sonic Anemometers ◽  
Two Component ◽  
The Cross

Abstract Two-component horizontal motion vectors of aerosol features were calculated by applying a cross-correlation algorithm to square image blocks extracted from consecutive pairs of elastic backscatter lidar scans. The resulting vector components were compared with corresponding horizontal wind components from tower-mounted sonic anemometers located at the center of the image blocks. In the analysis 180 245 pairs of vectors derived from 75 days of field data collected between 19 March and 11 June 2007 were used. Examples of time series comparisons from 4-h periods during light, strong, and changing wind conditions are presented. Mean signal-to-noise ratios (SNRs) of the block backscatter data, maxima of the cross-correlation functions (CCFs), observed wind speed, and turbulent kinetic energy (TKE) were also calculated for each velocity component comparison. The correlation between the lidar-derived motion components and sonic anemometer wind components tends to be highest during light wind conditions with low TKE. An empirical relationship is presented that enables the elimination of vectors that are likely to be significantly different than the anemometer measurement. When applied to the entire set of scans available, this quality control (QC) method increases the correlation between the two forms of measurements. Finally, the cross-correlation algorithm and QC method are applied to a mesh of locations over pairs of scans. Two examples of two-dimensional and two-component vector flow fields are shown. In one case, the flow field reveals a rotational circulation associated with a vortex and, in the other case, convergence and transport near the leading edge of a density current front.

scholarly journals Mathematical Models for Blood Flow Quantification in Dialysis Access Using Angiography: A Comparative Study

Diagnostics ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1771
Author(s):  
Nischal Koirala ◽  
Gordon McLennan
Keyword(s):  
Blood Flow ◽  
Curve Fitting ◽  
Cross Correlation ◽  
Blood Flow Rate ◽  
Flow Quantification ◽  
Dialysis Access ◽  
Gamma Variate ◽  
Correlation Algorithm ◽  
Angiography Suite ◽  
The Cross

Blood flow rate in dialysis (vascular) access is the key parameter to examine patency and to evaluate the outcomes of various endovascular interve7ntions. While angiography is extensively used for dialysis access–salvage procedures, to date, there is no image-based blood flow measurement application commercially available in the angiography suite. We aim to calculate the blood flow rate in the dialysis access based on cine-angiographic and fluoroscopic image sequences. In this study, we discuss image-based methods to quantify access blood flow in a flow phantom model. Digital subtraction angiography (DSA) and fluoroscopy were used to acquire images at various sampling rates (DSA—3 and 6 frames/s, fluoroscopy—4 and 10 pulses/s). Flow rates were computed based on two bolus tracking algorithms, peak-to-peak and cross-correlation, and modeled with three curve-fitting functions, gamma variate, lagged normal, and polynomial, to correct errors with transit time measurement. Dye propagation distance and the cross-sectional area were calculated by analyzing the contrast enhancement in the vessel. The calculated flow rates were correlated versus an in-line flow sensor measurement. The cross-correlation algorithm with gamma-variate curve fitting had the best accuracy and least variability in both imaging modes. The absolute percent error (mean ± SEM) of flow quantification in the DSA mode at 6 frames/s was 21.4 ± 1.9%, and in the fluoroscopic mode at 10 pulses/s was 37.4 ± 3.6%. The radiation dose varied linearly with the sampling rate in both imaging modes and was substantially low to invoke any tissue reactions or stochastic effects. The cross-correlation algorithm and gamma-variate curve fitting for DSA acquisition at 6 frames/s had the best correlation with the flow sensor measurements. These findings will be helpful to develop a software-based vascular access flow measurement tool for the angiography suite and to optimize the imaging protocol amenable for computational flow applications.

Flow Measurement with Digital Correlator Realized by FPGA

2012 ◽  
Vol 462 ◽  
pp. 641-646
Author(s):  
Yan Long Wang ◽  
Jun Hua Zhang ◽  
Lu Lu Bu ◽  
Jun Yang ◽  
Xin Ling Shi
Keyword(s):  
Measurement System ◽  
Flow Measurement ◽  
Cross Correlation ◽  
High Reliability ◽  
Gate Arrays ◽  
Time Flow ◽  
Field Programmable ◽  
Programmable Gate Arrays ◽  
The Cross ◽  
Digital Correlator

Cross correlator is the core device of the cross-correlation flow measurement system. This paper describes the theory of the cross-correlation flow measurement system and realizes the digital correlator for flow measurement based on field programmable gate arrays (FPGA). The correlation algorithm is realized by verilog language, and the result of Modelsim simulation shows that this correlator can be used to calculate the cross functions of random signal. This correlator which has a simple hardware structure, high reliability and high accuracy, can meet the demand of the real-time flow measurement system.

Astronomical Image Matching Based on the Cross-Correlation Algorithm

2014 ◽  
Vol 989-994 ◽  
pp. 3827-3833
Author(s):  
Ji Jun Sun
Keyword(s):  
Image Registration ◽  
Image Matching ◽  
Cross Correlation ◽  
Medical Image Analysis ◽  
Correlation Method ◽  
Remote Sensing Data ◽  
Correlation Algorithm ◽  
Astronomical Image ◽  
The Cross ◽  
Astronomical Images

Image registration is widely used in the areas of image fusion, target tracking, remote sensing data analysis, medical image analysis such as organization pathological changes, under the constantly exploring to the image registration technology. In this paper astronomical image matching based on the cross-correlation algorithm is proposed and we focuses on adopting the registration form using the cross-correlation method after segmenting the astronomical images. The method can effectively solve the difficulties of the overall matching, represent the salient regions of features and implement local matching.

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