Relations of the Laser Intensity Value, the Laser Ranging Value and the Laser Incident Angle

2012 ◽  
Vol 239-240 ◽  
pp. 198-201
Author(s):  
Xiao Jun Cheng ◽  
Kai Tan ◽  
Qi Ye Lou
Keyword(s):  
Experimental Data ◽  
Laser Intensity ◽  
Incidence Angle ◽  
Incident Angle ◽  
New Method ◽  
Theoretical Formula ◽  
Laser Ranging ◽  
Target Classification ◽  
Functional Relationships ◽  
Work Done

Firstly, the functional relationships of the laser intensity value, the target reflectance, the laser ranging value and the laser incidence angle was derived theoretically in this paper, and a new method of target classification based on the laser intensity value and the target reflectance was proposed. Then, the experimental data was analyzed to verify the correctness of the theoretical formula. Finally, the work done in this paper was summarized.

scholarly journals Airborne LiDAR Intensity Correction Based on a New Method for Incidence Angle Correction for Improving Land-Cover Classification

2021 ◽  
Vol 13 (3) ◽  
pp. 511
Author(s):  
Qiong Wu ◽  
Ruofei Zhong ◽  
Pinliang Dong ◽  
You Mo ◽  
Yunxiang Jin
Keyword(s):  
Classification Accuracy ◽  
Incidence Angle ◽  
Incident Angle ◽  
Laser Scanner ◽  
Airborne Lidar ◽  
New Method ◽  
Forest Monitoring ◽  
Measurement Unit ◽  
Intensity Data ◽  
Corrected Intensity

Light detection and range (LiDAR) intensity is an important feature describing the characteristics of a target. The direct use of original intensity values has limitations for users, because the same objects may have different spectra, while different objects may have similar spectra in the overlapping regions of airborne LiDAR intensity data. The incidence angle and range constitute the geometric configuration of the airborne measurement system, which has an important influence on the LiDAR intensity. Considering positional shift and rotation angle deviation of the laser scanner and the inertial measurement unit (IMU), a new method for calculating the incident angle is presented based on the rigorous geometric measurement model for airborne LiDAR. The improved approach was applied to experimental intensity data of two forms from a RIEGL laser scanner system mounted on a manned aerial platform. The results showed that the variation coefficient of the intensity values after correction in homogeneous regions is lower than that obtained before correction. The overall classification accuracy of the corrected intensity data of the first form (amplitude) is significantly improved by 30.01%, and the overall classification accuracy of the corrected intensity data of second form (reflectance) increased by 18.21%. The results suggest that the correction method is applicable to other airborne LiDAR systems. Corrected intensity values can be better used for classification, especially in more refined target recognition scenarios, such as road mark extraction and forest monitoring. This study provides useful guidance for the development of future LiDAR data processing systems.

Performance prediction of transonic axial multistage compressor based on one-dimensional meanline method

2021 ◽  
pp. 095765092199881
Author(s):  
Yingying Zhang ◽  
Shijie Zhang
Keyword(s):  
Experimental Data ◽  
Mass Flow ◽  
Flow Separation ◽  
Performance Prediction ◽  
Factor Model ◽  
Separation Method ◽  
Prediction Program ◽  
Blockage Factor ◽  
Reliability And Robustness ◽  
Work Done

This study proposes a 1D meanline program for the modeling of modern transonic axial multistage compressors. In this method, an improved blockage factor model is proposed. Work-done factor that varies with the compressor performance conditions is added in this program, and at the same time a notional blockage factor is kept. The coefficient of deviation angle model is tuned according to experimental data. In addition, two surge methods that originated from different sources are chosen to add in and compare with the new method called mass flow separation method. The salient issues presented here deal first with the construction of the compressor program. Three well-documented National Aerodynamics and Space Administration (NASA) axial transonic compressors are calculated, and the speedlines and aerodynamic parameters are compared with the experimental data to verify the reliability and robustness of the proposed method. Results show that consistent agreement can be obtained with such a performance prediction program. It was also apparent that the two common methods of surge prediction, which rely upon either stage or overall characteristic gradients, gave less agreement than the method called mass flow separation method.

scholarly journals Towards Transabdominal Functional Photoacoustic Imaging of the Placenta: Improvement in Imaging Depth Through Optimization of Light Delivery

2021 ◽  
Author(s):  
Kristie Huda ◽  
Kenneth F. Swan ◽  
Cecilia T. Gambala ◽  
Gabriella C. Pridjian ◽  
Carolyn L. Bayer
Keyword(s):  
Delivery System ◽  
Light Propagation ◽  
Ex Vivo ◽  
Photoacoustic Imaging ◽  
Incidence Angle ◽  
Incident Angle ◽  
Placental Tissue ◽  
Light Delivery ◽  
Imaging Depth ◽  
The Impact

AbstractFunctional photoacoustic imaging of the placenta could provide an innovative tool to diagnose preeclampsia, monitor fetal growth restriction, and determine the developmental impacts of gestational diabetes. However, transabdominal photoacoustic imaging is limited in imaging depth due to the tissue’s scattering and absorption of light. The aim of this paper was to investigate the impact of geometry and wavelength on transabdominal light delivery. Our methods included the development of a multilayer model of the abdominal tissue and simulation of the light propagation using Monte Carlo methods. A bifurcated light source with varying incident angle of light, distance between light beams, and beam area was simulated to analyze the effect of light delivery geometry on the fluence distribution at depth. The impact of wavelength and the effects of variable thicknesses of adipose tissue and muscle were also studied. Our results showed that the beam area plays a major role in improving the delivery of light to deep tissue, in comparison to light incidence angle or distance between the bifurcated fibers. Longer wavelengths, with incident fluence at the maximum permissible exposure limit, also increases fluence within deeper tissue. We validated our simulations using a commercially available light delivery system and ex vivo human placental tissue. Additionally, we compared our optimized light delivery to a commercially available light delivery system, and conclude that our optimized geometry could improve imaging depth more than 1.6×, bringing the imaging depth to within the needed range for transabdominal imaging of the human placenta.

An Implicit Off-Design Deviation Angle Correlation of Axial Flow Compressor Blade Elements

2017 ◽  
Author(s):  
Wu Dong-run ◽  
Teng Jin-fang ◽  
Qiang Xiao-qing ◽  
Feng Jin-zhang
Keyword(s):  
Experimental Data ◽  
Incidence Angle ◽  
High Reliability ◽  
Axial Flow ◽  
Compressor Blade ◽  
Deviation Angle ◽  
Axial Flow Compressor ◽  
New Correlation ◽  
Classical Correlations ◽  
Flow Compressor

This paper applies a new analytical/empirical method to formulate the off-design deviation angle correlation of axial flow compressor blade elements. An implicit function of deviation angle is used to map off-design deviation curves into linear correlations (minimum linear correlation coefficient R = 0.959 in this paper). Solution of the coefficients in the correlation is given through the study of classical theories and statistical analysis of the experimental data. The off-design deviation angle can be calculated numerically. The approach requires only knowledge of the blade element geometry. The comparison among 2 classical correlations and the new correlation proposed in this paper shows the new correlation has minimum error over the entire range of incidence angle while classical correlations show high reliability only in a limited range. Experimental data in this paper is collected from NASA’s open technical reports. Rotors and stators are studied together. Considering there is significant deviation angle variation along spanwise direction, only data at 50% span is studied, if possible. The error among experimental data, statistical regressions of the experimental data, and numerical results based on the new correlation is discussed. It has to be noted that the influence of the flow condition other than incidence angle is only being discussed but with less break through.

Behavior of Tip Leakage Flow Behind an Axial Compressor Rotor

1986 ◽  
Vol 108 (1) ◽  
pp. 7-14 ◽  
Author(s):  
M. Inoue ◽  
M. Kuroumaru ◽  
M. Fukuhara
Keyword(s):  
Incidence Angle ◽  
Axial Compressor ◽  
Performance Testing ◽  
Tip Clearance ◽  
Vortex Center ◽  
Tip Leakage Flow ◽  
Flow Measurements ◽  
Wall Boundary Layer ◽  
Compressor Rotor ◽  
Work Done

Performance testing and detailed flow measurements were made in an axial compressor rotor with various tip clearances. The experiments were conducted on the condition of the same incidence angle at midspan. Thus, the effect of tip clearance distinguished from that of incidence angle was investigated on the overall performance, work-done factor, blockage factor, and increases in displacement, momentum, and blade-force-deficit thicknesses of the casing wall boundary layer, The phase-locked flow patterns obtained by the multisampling technique show clear evidence of a leakage vortex core behind the rotor. Behavior of the leakage vortex was clarified for various tip clearances by examining loci of the vortex center, decay characteristics of the vorticity at the center, and the total amount of vorticity shed from the blade tip. These results were compared with the leakage vortex model presented by Lakshminarayana.

Energy exchanges during indentation tests in fresh-water ice

1991 ◽  
Vol 15 ◽  
pp. 247-253
Author(s):  
Devinder S. Sodhi
Keyword(s):  
Experimental Data ◽  
Heat Dissipation ◽  
Graphical Form ◽  
Small Scale ◽  
Water Ice ◽  
Structure Interaction ◽  
First Law Of Thermodynamics ◽  
Indentation Tests ◽  
Energy Exchanges ◽  
Work Done

The data from a small-scale experimental study on ice-structure interaction are used to compute the energy exchanges that take place during creep deformation and intermittent and continuous crushing of ice. The energy supplied by the carriage is partly stored in the structural spring, partly converted to kinetic energy, partly dissipated in deforming and extruding the ice and partly dissipated as heat in the damping mechanisms of the structure. Except for the heat dissipation, all other forms of energy were computed from the experimental data, and the heat dissipation was computed from the energy balance using the first law of thermodynamics. Plots of all forms of energy are shown in graphical form, in which their relative magnitudes, times of occurrence and interplay can be seen. The main result of this study is the thesis that intermittent crushing or ice-induced vibration takes place whenever there is an imbalance between the rates of work done by the carriage and the indentor and that there are no vibrations when these rates of work are equal.

Real-Time Prediction Method for Performance Degradation Trend Based on Reliability Experimental Data

2013 ◽  
Vol 321-324 ◽  
pp. 757-761 ◽  
Author(s):  
Chen Liang Song ◽  
Zhen Liu ◽  
Bin Long ◽  
Cheng Lin Yang
Keyword(s):  
Experimental Data ◽  
Real Time ◽  
Field Data ◽  
Prediction Method ◽  
Field Method ◽  
Performance Degradation ◽  
New Method ◽  
Time Prediction ◽  
Prediction Result ◽  
The Relationship

According to the real-time prediction for performance degradation trend, the commonly used method is just based on field data. But this methods prediction result will not be so much ideal when the fitting of degradation trend of field data is not good. To solve the problem, the paper introduces a new method which is not only based on field method but also based on reliability experimental data coming from the history experiment. We use the relationship between the field data and reliability experimental data to get the result of the two kinds of data respectively and then get the weights according to the two prediction results. Finally, the final real-time prediction result for performance degradation tendency can obtain by allocating the weights to the two prediction results.

A New Method to Assess Ductility of CFT Box Columns with Binding Bars under Axial Compression

2012 ◽  
Vol 446-449 ◽  
pp. 78-81 ◽  
Author(s):  
Yue Ling Long ◽  
Jian Cai
Keyword(s):  
Experimental Data ◽  
Axial Compression ◽  
Material Properties ◽  
New Method ◽  
Box Columns ◽  
Good Agreement

A new method based on material properties instead of experimental data was proposed to assess the ductility of concrete-filled steel box columns with binding bars and those without binding bars. Comparison between ductility coefficients based on experimental data and the calculated values by the proposed method shows good agreement.

A new method of determining the transport coefficients for high pressure arcs from experimental data

1969 ◽  
Vol 3 (2) ◽  
pp. 269-280 ◽  
Author(s):  
L. B. Kapp ◽  
P. H. Richards
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Computer Program ◽  
Numerical Method ◽  
Temperature Profile ◽  
Transport Coefficients ◽  
New Method ◽  
Radial Temperature ◽  
Current Voltage ◽  
Current Voltage Characteristics

The problem is to determine the electrical and thermal conductivities of high pressure are plasmas from measurements of the current—voltage characteristics of the are and a single radial temperature profile. A new numerical method is described together with the corresponding computer program. The latter is applied to some recent measurements on wall-stabilized nitrogen ares, covering the temperature range 4500—11,000 °K, for which radiation can be neglected, and the results are compared with those of other workers.

scholarly journals The Frequency Selective Effect of Radar Backscattering from Multiscale Sea Surface

2019 ◽  
Vol 11 (2) ◽  
pp. 160 ◽  
Author(s):  
Dengfeng Xie ◽  
Kun-Shan Chen ◽  
Jiangyuan Zeng
Keyword(s):  
Correlation Length ◽  
Incidence Angle ◽  
Incident Angle ◽  
Capillary Waves ◽  
Sea Surface ◽  
Validation Data ◽  
Effective Roughness ◽  
Spectral Components ◽  
Radar Backscattering ◽  
Radar Frequency

The sea surface essentially contains multiscale roughness with capillary waves of many sizes riding on large-scale waves that are also of many sizes. It is instructive to exploit the effect of radar frequency and observation geometry on the effective roughness scales responsible for radar backscattering so that the scattering mechanism and the scattering source can be better understood and quantitated. Based on common sea spectra and a theoretical scattering model, an attempt is made to attain the above objective. Model predictions, with selective roughness scales, are compared with wide validation data, including L-band radar observations, and predictions from C-band and Ku-band empirical models: geophysical model function (CMOD7) and NASA scatterometer (NSCAT-4) for C- and Ku-bands at different incident angles. Numerical results indicate that effective roughness scales for radar backscattering vary with radar frequency and incidence angle and are related to a portion of sea spectral components; the low limit of which is linearly proportional to the Bragg wavenumber determined by frequency and incidence angle, and the scale factor of the linear relationship is about 0.05. In addition, the root mean square (RMS) height and the correlation length of the effective roughness (i.e., scattering source) derived from the effective roughness decrease gradually as incident angle increases. In particular, the correlation length also linearly depends on the effective wavelength with a coefficient of 3.2. Moreover, these two coefficients are both independent of wind speed, radar frequency, and incident angle. These findings also reveal the essential properties of the spectral components contributing to radar backscattering and its variation with radar frequency and incident angle.

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