scholarly journals Strain Measurement Based on Speeded-up Robust Feature Algorithm Applied to Microimages from a Smartphone-Based Microscope

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2805 ◽  
Author(s):  
Botao Xie ◽  
Jinke Li ◽  
Xuefeng Zhao
Keyword(s):  
Health Monitoring ◽  
Strain Measurement ◽  
Measurement Method ◽  
Feature Points ◽  
Matching Effect ◽  
Point Tracking ◽  
Feature Point Tracking ◽  
M Estimator ◽  
Practical Engineering ◽  
Accuracy And Stability

The objective of this study is to evaluate and improve the accuracy and stability of a strain measurement method that uses the speeded-up robust feature (SURF) method to trace the displacement of feature points in microimages and obtain the strain in objects. The microimages were acquired using a smartphone with a portable microscope, which has a broad prospect of application. An experiment was performed using an unpacked optical fiber as the experimental carrier. The matching effect of the SURF method was analyzed in the microimage, and the M-estimator sample consensus (MSAC) algorithm was used to reject outliers generated by SURF. The results indicated that the accuracy of strain measurement using the proposed method is improved by modifying the feature point tracking method and measurement method. When compared with the fiber Bragg grating (FBG) data, the maximum standard error corresponded to 2.5 με, which satisfies the requirement of structural health monitoring (SHM) in practical engineering.

scholarly journals A New Rotor Position Measurement Method for Permanent Magnet Spherical Motors

2018 ◽  
Vol 8 (12) ◽  
pp. 2415 ◽  
Author(s):  
Yin Lu ◽  
Cungang Hu ◽  
Qunjing Wang ◽  
Yi Hong ◽  
Weixiang Shen ◽  
...  
Keyword(s):  
Permanent Magnet ◽  
High Speed ◽  
Measurement Method ◽  
Coordinate Frame ◽  
Feature Points ◽  
Position Measurement ◽  
Experimental Platform ◽  
Rotor Position ◽  
Straight Line ◽  
The World

This paper proposes a new high-precision rotor position measurement (RPM) method for permanent magnet spherical motors (PMSMs). In the proposed method, a LED light spot generation module (LSGM) was installed at the top of the rotor shaft. In the LSGM, three LEDs were arranged in a straight line with different distances between them, which were formed as three optical feature points (OFPs). The images of the three OFPs acquired by a high-speed camera were used to calculate the rotor position of PMSMs in the world coordinate frame. An experimental platform was built to verify the effectiveness of the proposed RPM method.

Feature point tracking in time-varying images

1990 ◽  
Vol 11 (12) ◽  
pp. 843-848 ◽  
Author(s):  
Paul M. Griffin ◽  
Sherri L. Messimer
Keyword(s):  
Feature Point ◽  
Time Varying ◽  
Point Tracking ◽  
Feature Point Tracking

An Approach to Analyse Errors Introduced in the Random Grid Strain Measurement Method

Strain ◽  
2008 ◽  
Vol 46 (3) ◽  
pp. 258-266 ◽  
Author(s):  
A. P. Iliopoulos ◽  
N. P. Andrianopoulos
Keyword(s):  
Strain Measurement ◽  
Measurement Method ◽  
Random Grid

scholarly journals Vision-based Deformation Measurement for Pile-soil Testing

2019 ◽  
Vol 275 ◽  
pp. 03009
Author(s):  
Kun Zhou ◽  
Linhua Chen ◽  
Shanshan Yu
Keyword(s):  
Measurement Method ◽  
Optical Measurement ◽  
High Sensitivity ◽  
Steel Tube ◽  
Image Features ◽  
Deformation Measurement ◽  
Measurement Technology ◽  
Full Field ◽  
Progressive Development ◽  
Point Tracking

Image measurement technology has been widely used in monitoring the deformation of the soil field around the pile with its advantages of no damage, no contact, full-field measurement, no added quality and high sensitivity. But there are few researches on image-based bearing deformation measurement of the pile. Through an indoor pile-soil semi-model test, the rigid body displacement and load-bearing deformation of a new type of prefabricated steel tube pile foundation under horizontal load was measured based on image features. In this study, the concept of optical extensometer is first applied to the measurement of local average strain of a non-uniform deformed structure. Based on an improved feature point tracking algorithm SURF-BRISK, non-contact measurement of tiny strain of pile body is realized. In addition, based on DIC technology, this study also obtained the progressive development of displacement field of soil around pile. The above work fully reflects the non-contact convenience and full-field richness of the optical measurement method compared with the traditional measurement method.

The Measurement of Dynamic Stress for The Top-Cutter Machine of Cotton

2010 ◽  
Vol 34-35 ◽  
pp. 1323-1327 ◽  
Author(s):  
Chun Mei Xu ◽  
Chun Yao Wang ◽  
Fa Chen ◽  
Min Lei ◽  
Yong Xin Jiang ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Strain Measurement ◽  
Measurement Method ◽  
Dynamic Stress ◽  
Stress Condition ◽  
Dynamic Strain ◽  
Measurement Result

In this paper, we used the dynamic strain measurement method to measure the top-cutter machine of cotton’s stress under its working state. With sorting out data and analyzing it, we obtained the stress condition of the framing and the working parts. And the measurement result could be used to analyze the axle’s fatigue strength and check whether it was safe or not. It provided integrant basis for the further design of the machine.

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