scholarly journals Improved FCM algorithm for fisheye image cluster analysis for tree height calculation

2021 ◽  
Vol 18 (6) ◽  
pp. 7806-7836
Author(s):  
Jiayin Song ◽  
◽  
Yue Zhao ◽  
Zhixiang Chi ◽  
Qiang Ma ◽  
...  
Keyword(s):  
Relative Error ◽  
Measurement Accuracy ◽  
Tree Height ◽  
Measuring Method ◽  
High Accuracy ◽  
Fisheye Lens ◽  
Important Index ◽  
Standing Trees ◽  
Clustering Effect ◽  
Shooting Distance

<abstract> <p>The height of standing trees is an important index in forestry research. This index is not only hard to measure directly but also the environmental factors increase the measurement difficulty. Therefore, the measurement of the height of standing trees is always a problem that experts and scholars are trying to improve. In this study, improve fuzzy c-means algorithm to reduce the calculation time and improve the clustering effect, used on this image segmentation technology, a highly robust non-contact measuring method for the height of standing trees was proposed which is based on a smartphone with a fisheye lens. While ensuring the measurement accuracy, the measurement stability is improved. This method is simple to operate, just need to take a picture of the standing tree and determine the shooting distance to complete the measurement. The purpose of the fisheye lens is to ensure that the tree remains intact in the photograph and to reduce the shooting distance. The results of different stability experiments show that the measurement error ranged from -0.196m to 0.195m, and the highest relative error of tree measurement was 3.05%, and the average relative error was 1.45%. Analysis shows that compared with previous research, this method performs better at all stages. The proposed approach can provide a new way to obtain tree height, which can be used to analyze growing status and change in contrast height because of high accuracy and permanent preservation of images.</p> </abstract>

Detecting Thread Features Based on Digital Image Processing Techniques

2014 ◽  
Vol 889-890 ◽  
pp. 1107-1110
Author(s):  
Han Ming Cai ◽  
Pei Yao Wang ◽  
Xiao Mei Song
Keyword(s):  
Image Processing ◽  
Digital Image Processing ◽  
Digital Image ◽  
Measurement Accuracy ◽  
Measuring Method ◽  
Image Processing Techniques ◽  
Basic Image ◽  
The Cost ◽  
Processing Techniques ◽  
Gauge Measurement

Thread features of the traditional measuring method mainly adopts working gauge measurement, due to limitations in the traditional thread features measurement accuracy is relatively low, the efficiency is low, the cost is high. The thread features detection method based on digital image processing techniques using CCD to obtain basic image of thread, processing the thread image, extracting thread outline, calculating thread features through the computer, improves the efficiency, saves the cost.

scholarly journals Assessment of the Accuracy of a Multi-Beam LED Scanner Sensor for Measuring Olive Canopies

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4406 ◽  
Author(s):  
Rafael Sola-Guirado ◽  
Sergio Bayano-Tejero ◽  
Antonio Rodríguez-Lizana ◽  
Jesús Gil-Ribes ◽  
Antonio Miranda-Fuentes
Keyword(s):  
Laboratory Test ◽  
Real Time ◽  
Relative Error ◽  
Laser Scanner ◽  
Field Tests ◽  
High Accuracy ◽  
Field Conditions ◽  
Canopy Trees ◽  
Canopy Volume

Canopy characterization has become important when trying to optimize any kind of agricultural operation in high-growing crops, such as olive. Many sensors and techniques have reported satisfactory results in these approaches and in this work a 2D laser scanner was explored for measuring canopy trees in real-time conditions. The sensor was tested in both laboratory and field conditions to check its accuracy, its cone width, and its ability to characterize olive canopies in situ. The sensor was mounted on a mast and tested in laboratory conditions to check: (i) its accuracy at different measurement distances; (ii) its measurement cone width with different reflectivity targets; and (iii) the influence of the target’s density on its accuracy. The field tests involved both isolated and hedgerow orchards, in which the measurements were taken manually and with the sensor. The canopy volume was estimated with a methodology consisting of revolving or extruding the canopy contour. The sensor showed high accuracy in the laboratory test, except for the measurements performed at 1.0 m distance, with 60 mm error (6%). Otherwise, error remained below 20 mm (1% relative error). The cone width depended on the target reflectivity. The accuracy decreased with the target density.

scholarly journals High-Accuracy Calibration Based on Linearity Adjustment for Eddy Current Displacement Sensor

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2842 ◽  
Author(s):  
Wei Liu ◽  
Bing Liang ◽  
Zhenyuan Jia ◽  
Di Feng ◽  
Xintong Jiang ◽  
...  
Keyword(s):  
Eddy Current ◽  
Measurement Accuracy ◽  
Characteristic Curve ◽  
Calibration Method ◽  
High Accuracy ◽  
Output Characteristic ◽  
Displacement Sensor ◽  
Support Vector ◽  
Displacement Sensors ◽  
Calibration Accuracy

High precision position control is essential in the process of parts manufacturing and assembling, where eddy current displacement sensors (ECDSs) are widely used owing to the advantages of non-contact sensing, compact volume, and resistance to harsh conditions. To solve the nonlinear characteristics of the sensors, a high-accuracy calibration method based on linearity adjustment is proposed for ECDSs in this paper, which markedly improves the calibration accuracy and then the measurement accuracy. After matching the displacement value and the output voltage of the sensors, firstly, the sensitivity is adjusted according to the specified output range. Then, the weighted support vector adjustment models with the optimal weight of the zero-scale, mid-scale and full-scale are established respectively to cyclically adjust the linearity of the output characteristic curve. Finally, the final linearity adjustment model is obtained, and both the calibration accuracy and precision are verified by the established calibration system. Experimental results show that the linearity of the output characteristic curve of ECDS adjusted by the calibration method reaches over 99.9%, increasing by 1.9–5.0% more than the one of the original. In addition, the measurement accuracy improves from 11–25 μ m to 1–10 μ m in the range of 6mm, which provides a reliable guarantee for high accuracy displacement measurement.

Study on the Engine Speed Sensor Position Measuring Tool Based on Minitab

2013 ◽  
Vol 456 ◽  
pp. 211-215
Author(s):  
Wu Cen ◽  
Li Xia Xia
Keyword(s):  
Measurement Accuracy ◽  
Engine Speed ◽  
Measurement Data ◽  
Measuring Method ◽  
Speed Sensor ◽  
Sensor Position ◽  
Accuracy Of Measurement ◽  
Repeatability And Reproducibility ◽  
Measuring Tool ◽  
Engine Size

Research on key position speed sensor of automobile engine size measuring tool as an example, for studying the optimization of measuring tools through use the powerful Minitab software statistics, analysis and calculation functions. Randomly selected 10 parts as a measurement sample, then obtained the measurement data by experiment. Analysis of the measured data with Minitab and calculate the repeatability and reproducibility of the device. Find the causes of failure in measuring and explore how to optimize the measuring method. Improved measuring clamp structure, and through experiments verify its feasibility. Thereby solving the problem of measuring failure to ensure the accuracy of measurement data, and improve the measurement accuracy of the product.

Signal Sampling and Accuracy Analysis of Large Gear’s Angular Displacement Measuring its Deviation On-Machine

2011 ◽  
Vol 189-193 ◽  
pp. 4201-4204
Author(s):  
Jia Qi Jin ◽  
Hui Li
Keyword(s):  
Measurement Accuracy ◽  
Angular Displacement ◽  
Total Error ◽  
Measuring Method ◽  
Displacement Measurement ◽  
Signal Acquisition ◽  
Accuracy Analysis ◽  
Friction Disc ◽  
Large Gear ◽  
Circular Grating

To solve the critical problem of large gear deviation on-machine: angle displacement measurement that is how to get signal acquisition and accuracy analysis of angle displacement. A new measuring method is proposed, which applies the dividing mechanism (it is composed of friction disc and circular grating) to ensure index and pick up signal of gear corner correctly and strictly according to the principle of angular displacement measurement. Furthermore, the main error which affects measurement accuracy is analyzed, and accuracy is analyzed with geometrical theory such as Fourier series and error synthesis principle etc. The experimental results indicate that angel dividing and signal samplings are easier and more efficient by the dividing mechanism, furthermore, the accuracy is in the range of total error that is permitted by verification, and the mechanism can also meet the requirement of high accuracy, so the method is significance that assessing transmission accuracy of involutes gear.

scholarly journals Open-Ended Coaxial Cable Selection for Measurement of Liquid Dielectric Properties via the Reflection Method

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Jingchen Wang ◽  
Eng Gee Lim ◽  
Mark Paul Leach ◽  
Zhao Wang ◽  
Ka Lok Man
Keyword(s):  
Dielectric Properties ◽  
Reflection Coefficient ◽  
Relative Error ◽  
Measurement Accuracy ◽  
Liquid Dielectric ◽  
Coaxial Cable ◽  
Dielectric Measurement ◽  
Reflection Method ◽  
Careful Choice ◽  
Selection For

An open-ended coaxial cable is used to measure the dielectric properties of lossy liquid. The method which is based on the measurement of the reflection coefficient of the open-ended cable makes it easy to operate and postprocess. To meet the accuracy requirements, the dimensions of the coaxial cable need to be taken into consideration; therefore, it is necessary to select an appropriate coaxial cable for the measurement. This paper investigates the influence of cable dimensions on dielectric measurement accuracy. With careful choice of the coaxial cable, the relative error of calculated results can be less than 0.1%.

Assessment of the Pulpwood Quality of Standing Trees Using near Infrared Spectroscopy

1998 ◽  
Vol 6 (A) ◽  
pp. A117-A123 ◽  
Author(s):  
L. R. Schimleck ◽  
A. J. Michell ◽  
C. A. Raymond ◽  
A. Muneri
Keyword(s):  
Near Infrared ◽  
Nir Spectroscopy ◽  
Tree Height ◽  
Tree Breeding ◽  
Pulp Yield ◽  
Calibration Model ◽  
Standing Trees ◽  
Sampling Height ◽  
Individual Trees ◽  
Whole Tree

In Australia, considerable effort has been directed at improving the pulp yield of plantation grown trees through tree breeding programs. However, an improvement in pulp yield relies on the assessment of large numbers of trees. Traditional methods of assessment are expensive, time consuming and destructive, inhibiting their use. Cores can be extracted non-destructively from standing trees using TRECOR, a handheld motor driven drill. The cores are milled, their near-infrared spectra obtained and pulp yield estimated using an appropriate calibration model. The height at which the core is taken is very important. It must represent the whole tree and sampling must be easy and practical. The longitudinal and radial (within-tree) variation of pulp yield for 15 Eucalyptus nitens trees was examined using near-infrared (NIR) spectroscopy. The trees were taken from three families (five trees per family) selected for giving high, medium and low pulp yields respectively. Three trees (one from each family) were examined in detail. Maps of within-tree variation of pulp yield were developed. Pulp yield was found to be highly variable within individual trees and between trees of the same family. The yield of samples from 10% of tree height (approximately 2.2 m) gave the best correlation with whole-tree yield. Samples from 5% of tree height (approximately 1.1 m) gave a slightly lower correlation but provided a more convenient sampling height. Ten Eucalyptus globulus and ten E. nitens trees growing on five sites in Australia were used to examine the longitudinal variation of pulp yield. Trees from sites in Tasmania, Western Australia and Victoria were sampled. The optimal sampling height for E. globulus was 1.1 m. No single sampling height could be recommended for E. nitens due to large site effects.

Analysis of Underground Space Azimuth Measuring and Data Processing in a Tunnel

2014 ◽  
Vol 580-583 ◽  
pp. 2828-2832
Author(s):  
Tao Wang ◽  
Hu Rong Duan ◽  
Liu Tao Jiang ◽  
Shun Liu
Keyword(s):  
Measurement Error ◽  
Data Processing ◽  
Measurement Accuracy ◽  
High Accuracy ◽  
Measurement Precision ◽  
Underground Space ◽  
Processing Theory ◽  
Constant Measurement ◽  
Survey Results ◽  
Final Orientation

In this paper, we studied high accuracy azimuth measuring on improving the precision of traverse azimuth from the perspective of transfixion measurement error in a tunnel project. On the basis of a feasible scheme using Gyro Total Station measurement is given. Data processing theory and method are also introduced with a successful tunnel transfixion case. The transfixion results show that the instrument constant measurement precision is 3.7", baseline coordinates azimuth measurement accuracy is 4.8" into tunnel, the final orientation coordinate azimuth value and traverse measurement values differ is 11", to guide the construction of the gyro orientation with survey results achieved tunnel through smoothly.

scholarly journals Passenger Flow Prediction of Integrated Passenger Terminal Based on K-Means–GRNN

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Yifan Tan ◽  
Haixu Liu ◽  
Yun Pu ◽  
Xuemei Wu ◽  
Yubo Jiao
Keyword(s):  
Prediction Model ◽  
Cluster Algorithm ◽  
Flow Distribution ◽  
High Accuracy ◽  
Distribution Center ◽  
Passenger Transport ◽  
Passenger Flow ◽  
Flow Prediction ◽  
Passenger Travel ◽  
Clustering Effect

As the passenger flow distribution center cooperating with various modes of transportation, the comprehensive passenger transport hub brings convenience to passengers. With the diversification of passenger travel modes, the passenger flow scale gradually increases, which brings significant challenges to the integrated passenger hub. Therefore, it is urgent to solve the problem of early warning and response to the future passenger flow to avoid congestion accidents. In this paper, the passenger flow GRNN prediction model is proposed, based on the K-means cluster algorithm, and an improved index named BWPs (Between-Within Proportion-Similarity) is proposed to improve the clustering effect of K-means so that the clustering effect of the new index is verified. In addition, the passenger flow data are studied and trained by combining with the GRNN neural network model based on parameter optimization (GA); the passenger flow prediction model is obtained. Finally, the passenger flow of Chengdu East Railway Station has been taken as an example, which is divided into 16 models, and each type of passenger flow is predicted, respectively. Compared with the traditional method, the results show that the model can predict the passenger flow with high accuracy.

scholarly journals Акустический расходомер

2019 ◽  
Vol 89 (9) ◽  
pp. 1434
Author(s):  
В.А. Бузановский
Keyword(s):  
Relative Error ◽  
Flow Rate ◽  
High Speed ◽  
Volume Flow Rate ◽  
High Accuracy ◽  
Volume Flow ◽  
Metrological Characteristics ◽  
Simple Design ◽  
Liquid Substance

The design and metrological characteristics of the acoustic flowmeter of a flow of a gaseous or liquid substance are considered. It is shown that the device has a simple design, is characterized by high accuracy (relative error of measuring the volume flow rate is less than 1%) and high speed (the time to determine the flow rate is not more than a few milliseconds).

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