scholarly journals Vision-based Size Estimation and Centroid Positioning of Partially Occluded Fruits

2020 ◽  
Vol 37 (3) ◽  
Author(s):  
Nay Zar Aung ◽  
Mya Thin Kyu Kyu Kyu
Keyword(s):  
Processing Time ◽  
Experimental Tests ◽  
Conic Section ◽  
Circle Fitting ◽  
Size Estimation ◽  
Image Processing Algorithm ◽  
Mathematical Properties ◽  
Fitting Method ◽  
Partially Occluded ◽  
Robust Prediction

The objective of this study was to propose a simple and efficient image processing algorithm for estimating the size and centroid of partially occluded round fruits. In the proposed method, the size and centroid of partially occluded fruit were estimated based on the mathematical properties of the arc-radius. The experimental tests were conducted in a laboratory with orange, Sunkist, apple, and tomato fruits by setting different occlusion conditions. The occlusion percentage was varied between 0% and 90%. The accuracy and processing time of the proposed method were compared with that of the widely-used conic-section circle fitting method. The results showed that the proposed method resulted in an overall accuracy of 95.1% and processing time of 0.66 s, as opposed to 60.2% and 0.68 s, respectively, using the conic-section equation. Compared with the conic-section equation, the proposed method was able to give a more robust prediction, even for low resolution images.

Long Range Pupil Location Algorithm Based on the Improved Circle Fitting Method

2019 ◽  
pp. 295-303
Author(s):  
Yongliang Zhang ◽  
Xiaoxiao Qian ◽  
Zhongsu Luo ◽  
Keyi Zhu ◽  
Minjun Yu
Keyword(s):  
Long Range ◽  
Circle Fitting ◽  
Fitting Method ◽  
Location Algorithm

scholarly journals Debonding Size Estimation in Reinforced Concrete Beams Using Guided Wave-Based Method

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 389 ◽  
Author(s):  
Beata Zima ◽  
Rafał Kędra
Keyword(s):  
Reinforced Concrete ◽  
Guided Waves ◽  
Concrete Beams ◽  
Load Capacity ◽  
Experimental Tests ◽  
Concrete Cover ◽  
Guided Wave ◽  
Reinforced Concrete Beams ◽  
Size Estimation ◽  
Advantages And Disadvantages

The following paper presents the results of the theoretical and experimental analysis of the influence of debonding size on guided wave propagation in reinforced concrete beams. The main aim of the paper is a development of a novel, baseline-free method for determining the total area of debonding between steel rebar embedded in a concrete cover on the basis of the average wave velocity or the time of flight. The correctness of the developed relationships was verified during the experimental tests, which included propagation of guided waves in concrete beams with the varying debonding size, shape and location. The analysis of the collected results proved that guided waves can be efficiently used not only in the debonding detection, but also in an exact determining of its total area, which is extremely important in the context of the nondestructive assessment of the load capacity of the reinforced concrete structures. The undeniable advantage of the proposed method is that there are no requirements for any baseline signals collected for an undamaged structure. The paper comprises of the detailed step by step algorithm description and a discussion of both the advantages and disadvantages.

Radius Constraint Least-Square Circle Fitting Method

2011 ◽  
Vol 411 ◽  
pp. 241-244
Author(s):  
Qiang Zhu ◽  
Guo Hui Zhang ◽  
Zhen Xu
Keyword(s):  
Circle Method ◽  
Least Square Method ◽  
Least Square ◽  
Circle Fitting ◽  
Excellent Performance ◽  
Testing Environment ◽  
Least Square Fitting ◽  
Fitting Method ◽  
Radius Constraint ◽  
Short Arc

Short arc usually lost the most part of information in measurement, therefore the fitting center can not be found accurately. The shortage of least-square method is analyzed in short arc fitting. The uncertainty of fitting center direction and fitting radius is illustrated. And we derived the solution to estimation of fitting center direction. Base on the testing environment, radius constraint least-square fitting circle method is proposed. Simulations demonstrated excellent performance of this algorithm.

scholarly journals An Approximate Estimation Approach of Fault Size for Spalled Ball Bearing in Induction Motor by Tracking Multiple Vibration Frequencies in Current

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1631 ◽  
Author(s):  
Chidong Qiu ◽  
Xinbo Wu ◽  
Changqing Xu ◽  
Xiang Qiu ◽  
Zhengyu Xue
Keyword(s):  
Experimental Tests ◽  
Friction Torque ◽  
Vibration Frequencies ◽  
Size Estimation ◽  
Characteristic Vibration ◽  
Multiple Characteristic ◽  
Fault Features ◽  
Approximate Estimation ◽  
Voltage Frequency ◽  
Harsh Conditions

Fault size estimation is of great importance to bearing performance degradation assessment and life prediction. Until now, fault size estimation has generally been based on acoustic emission signals or vibration signals; an approach based on current signals has not yet been mentioned. In the present research, an approximate estimation approach based on current is introduced. The proposed approach is easy to implement for existing inverter-driven induction motors without complicated calculations and additional sensors, immune to external disturbances, and suitable for harsh conditions. Firstly, a feature transmission route from spall, to Hertzian forces, and then to friction torque is simulated based on a spall model and dynamic model of the bearing. Based on simulated results, the relation between spall size and the multiple characteristic vibration frequencies in friction torque is revealed. Secondly, the multiple characteristic vibration frequencies modulated in the current is investigated. Analysis results show that those frequencies modulated in the current are independent of each other, without spectrum overlap. Thirdly, to address the issue of which fault features modulated in the current are very weak, a fault-feature-highlighting approach based on reduced voltage frequency ratio is proposed. Finally, experimental tests were conducted. The obtained results validate that the proposed approach is feasible and effective for spall size estimation.

An Ellipse Fitting Algorithm Applied to the Construction of the Elliptic Arc-Shaped Leading Edge

2013 ◽  
Vol 744 ◽  
pp. 232-238
Author(s):  
Xiao Qiang Yu ◽  
Tao Ning ◽  
Yong Long Hou ◽  
Zhi Tong Chen
Keyword(s):  
Numerical Experiments ◽  
Leading Edge ◽  
Ellipse Fitting ◽  
Circle Fitting ◽  
Tangential Contact ◽  
Contact Constraint ◽  
Fitting Method ◽  
Fitting Algorithm ◽  
Strong Robustness ◽  
Precision And Accuracy

In this paper, we proposed a new ellipse fitting method converting the ellipse fitting into a circle fitting based on projection transformation. Numerical experiments demonstrate that our approach have good stability and strong robustness against noise in addition to excellent precision and accuracy. In our further research, we successfully extend our algorithm to the construction of the elliptic arc-shaped leading edge by using a tangential contact constraint. Keywords: Ellipse fitting; Projection; PSO; Leading edge

A nested circle-fitting method for micro-hole centering and its application in electrochemical deburring

2019 ◽  
Vol 233 (12) ◽  
pp. 2292-2305 ◽  
Author(s):  
Quancun Kong ◽  
Guili Liu ◽  
Xiahui Fan ◽  
Zhiqiang Wang ◽  
Dong Li ◽  
...  
Keyword(s):  
High Performance ◽  
Least Square Method ◽  
Linear Constraint ◽  
Least Square ◽  
Maximum Deviation ◽  
Circle Fitting ◽  
Accuracy Rate ◽  
Machined Surface ◽  
Fitting Method ◽  
Micro Hole

To solve these problems (i.e. the accuracy rate and stability of the centering) of enabling secondary machining of micro-holes with a size of 0.1 to 1 mm in high-performance metal alloy parts, a non-standard nested circle-fitting least-square method, with a linear constraint passing through the center (least square method with linear constraint [LSLC]), is proposed in this article. The experimental results show that the center of the circle is fitted with a maximum deviation of ±1.5 µm and good fitting precision, compared to other existing approaches. At the same time, the accuracy rate is increased by at least 20%, delivering a result of more than 99%, so the accuracy of the fitting and the stability of the centering are significantly improved. Finally, the new method is applied in actual micro-hole electrochemical deburring study. With the overall goal of ensuring centering, a rough-and-fine deburring process has been explored. On the premise that the hole is not expanded, the burrs have been quickly and completely removed, and machined surface roughness, Ra, has also reduced from 1.2 to 0.52 µm. The experiment has provided concrete validation of the feasibility of the nested circle-fitting method we have proposed.

Research on the Recursive and Step-by-Step Algorithm for Extraction of Point Laser Spot Center

2014 ◽  
Vol 1079-1080 ◽  
pp. 991-997
Author(s):  
Xu Xiao Hu ◽  
Ji Li ◽  
Ming Min Yang
Keyword(s):  
Laser Spot ◽  
Second Step ◽  
Circle Fitting ◽  
Step Method ◽  
Centroid Method ◽  
Oil Droplet ◽  
Spot Center ◽  
Fitting Method ◽  
Step Algorithm ◽  
Block Center

Whentesting the flatness of plate iron, if there is no disturbance in the spotdetection, the traditional centroid method and circle fitting method can bewell applied to extract the point laser spot center. However, the disturbanceof droplets, dusts, oil droplet and other factors are unavoidably in thepractical projects, and then the detection precision will falls sharply. In orderto solve the problem, the recursive and step-by-step method of extracting pointlaser spot center is proposed. There are two steps in this method.The thresholdcentroid method is used as the first step to extract the spots which containthe black blocks. The second step is to construct the template whose center hasa black block, then extract the black block center by running phase correlationalgorithm and the center is just the center of the point laser spot. Theresults of experiments verify that the precision of the spot center coordinateextracted by the proposed method is obviously higher than that extracted by thecentroid method and the circle fitting method with the disturbance of droplets.

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