Dynamic measurement method for pointing accuracy of communication antenna based on multi-view stereo vision

2020 ◽  
Author(s):  
Changyu Long ◽  
Zhang Bin ◽  
Yi Wangmin ◽  
Ruan Guowei ◽  
Wang Wei ◽  
...  
Keyword(s):  
Stereo Vision ◽  
Measurement Method ◽  
Dynamic Measurement ◽  
Pointing Accuracy

Research on Damage Status of the Reinforced Concrete Ground Floor Columns

2012 ◽  
Vol 226-228 ◽  
pp. 1436-1440
Author(s):  
Li Jun Gao ◽  
Yong Sheng Zhang ◽  
Qin Li
Keyword(s):  
Reinforced Concrete ◽  
Measurement Method ◽  
Damping Ratio ◽  
Simple Calculation ◽  
Dynamic Measurement ◽  
Concrete Column ◽  
Destructive Testing ◽  
Reinforced Concrete Column ◽  
First Order ◽  
Vibration Model

In this paper, dynamic measurement method is applied to test the damage of the bottom reinforced concrete column. The comparison between the calculated first order frequency of the bottom reinforced concrete column and the measured first order frequency shows that the result is consistent. This indicates that this approach is feasible. However, in recent years, dynamic measurement method is widely used in non-destructive testing of bridges and floors. The principle of the dynamic measurement method for the detection of reinforced concrete column utilizes the measured natural frequency, vibration model and damping ratio of reinforced concrete column and such inherent dynamic characteristics of indicators to reflect the damage of reinforced concrete column. And there is no secondary injury for the column. The simplified method of structure dynamics is applied to calculate the frequency of the bottom reinforced concrete column. And the simple calculation method is verified by experiment and practice.

Accurate profile measurement method for industrial stereo-vision systems

Sensor Review ◽  
2020 ◽  
Vol 40 (4) ◽  
pp. 445-453
Author(s):  
Yang Zhang ◽  
Wei Liu ◽  
Yongkang Lu ◽  
Xikang Cheng ◽  
Weiqi Luo ◽  
...  
Keyword(s):  
Stereo Vision ◽  
Measurement Method ◽  
Vision System ◽  
Practical Implication ◽  
Image Features ◽  
Reference Points ◽  
Profile Measurement ◽  
Surface Boundary ◽  
Content Type ◽  
Profile Reconstruction

Purpose Profile measurement with boundary information plays a vital role in the detection of quality in the assembly of aviation parts. The purpose of this paper is to improve the evaluation accuracy of the aerodynamic shapes of airplanes, the profiles of large-sized parts need to be measured accurately. Design/methodology/approach In this paper, an accurate profile measurement method based on boundary reference points is proposed for the industrial stereo-vision system. Based on the boundary-reference points, the authors established a priori constraint for extracting the boundary of the measured part. Combining with the image features of background and the measured part, an image-edge compensation model is established to extract the boundary of the measured part. The critical point of a laser stripe on the edge of the measured part is extracted corresponding to the boundary constraint. Finally, as per the principle of binocular vision, the profile of the measured part is reconstructed. Finding Laboratory experiments validate the measurement accuracy of the proposed method which is 0.33 mm. In the analysis of results between the measured data and the theoretical model, the measuring accuracy of the proposed method was found to be significantly higher than that of the other traditional methods. Practical implication An aviation part was measured in the part-assembly shop by the proposed method, which verified the feasibility and effectiveness of this method. The research can realize the measurement of smooth surface boundary which can solve existing profile reconstruction problems for aviation parts. Originality/value According to the two-dimensional contour constraint, critical points of the laser strip sequence at the edge of measured part are extracted and the accurate profile reconstruction with the boundary is realized.

scholarly journals An Efficient Pose Measurement Method of a Space Non-Cooperative Target Based on Stereo Vision

IEEE Access ◽  
2017 ◽  
Vol 5 ◽  
pp. 22344-22362 ◽  
Author(s):  
Jianqing Peng ◽  
Wenfu Xu ◽  
Han Yuan
Keyword(s):  
Stereo Vision ◽  
Measurement Method

The robustness verification of the D-VHS trick play using dynamic measurement method for evaluating mechanism

2000 ◽  
Vol 46 (3) ◽  
pp. 481-486
Author(s):  
M. Matsumaru ◽  
T. Ohishi ◽  
T. Eino ◽  
Y. Togo ◽  
M. Tsuruta
Keyword(s):  
Measurement Method ◽  
Dynamic Measurement

Model Acquisition for Modal Analysis of Flexible Media Based on Stereo Vision

2014 ◽  
Author(s):  
Yen-Hao Chang ◽  
Jen-Yuan (James) Chang
Keyword(s):  
Modal Analysis ◽  
Stereo Vision ◽  
Manufacturing Process ◽  
Measurement Method ◽  
Metal Sheet ◽  
Mode Shapes ◽  
Shape Information ◽  
Sheet Rolling ◽  
The Media ◽  
Significant Change

To enhance and ensure machine reliability and accuracy, obtaining its mechanical properties in real-time dynamic conditions is of engineering importance. In both roll to roll printing and metal sheet rolling processes, it is well known that any misalignment or orientation arrangement between rollers can significant change stress distribution in the high speed transporting flexible media, leading to quite different dynamic responses in the manufacturing process. In sheet metal manufacturing process, to eliminate residual in the flexible media, it is a common process to place two adjacent rollers at different orientations and location, causing the media to deform largely and even to twist. In this case, common non-contact vibration measurement method using either single point or scanning laser Doppler vibrometry cannot accurately capture the vibratory response from the media due to the significant change in geometry to scatter the reflective laser light. In this paper, instead of adjusting the laser perpendicular to the curved surface of the media at each measurement point to capture modal information through experimental modal analysis, which is achieved by utilizing the excitation and measurement apparatuses to directly discover the modes of the media, a novel non-contact measurement method is proposed by using stereo vision to first acquire the shape of the flexible homogeneous metal sheet through one camera with a fixed focal length from two different views, and then calculate the coordinate by computer vision algorithm. The calculated coordinates and shape information will be input to the commercial FEA software and compute its modal information, namely natural frequencies and mode shapes. Lastly, the results gained by the method proposed will be compared with that acquired directly by the experimental methods.

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