An Imaging Processing Method for Stress Wave Reflection Period Extracting to Measure Guardrail Column Length

Author(s):  
Panpan Gong ◽  
Mingzhang Luo ◽  
Chuan Xu ◽  
Luoyu Zhou
1962 ◽  
Vol 29 (2) ◽  
pp. 440-440
Author(s):  
S. D. Weiner

2012 ◽  
Vol 446-449 ◽  
pp. 2229-2233 ◽  
Author(s):  
Xian Kai Bao ◽  
Yi Li

Bolt has been used widely in geoengineering all over the world in recent years, the testing technique of bolt develops quickly too. This paper summarizes simply the history of bolt testing technique, describes in detail stress wave reflection method. It is useful and valuable nondestructive.Testing method is verified with several parameters which estimate quality of bolting integrity.


Author(s):  
Chuan Xu ◽  
Mingzhang Luo ◽  
Chuang Hei ◽  
Gangbing Song

A roadway guardrail, as the driver’s last safety barrier, is an important part of a transportation system. The buried depth of the metal pipe directly determines the bearing capacity of the guardrail during an impact. It is important to estimate the buried depth during the inspection of a guardrail system. In this paper, we proposed an original method by integrating wavelet denoising, multiple self-correlation analysis (MSA) and energy spectrum analysis (ESA) to estimate the length of buried metal pipe based on the stress wave reflection. The stress wave is initiated by an impact on the exposed end of the buried pipe and stress wave reflection is detected by a PZT (Lead Zirconate Titanate) transducer. To execute the proposed method, firstly, Wavelet denoising is used to process the reflected stress wave signal to improve the signal-to-noise ratio. Then, the MSA detects the major frequency of the reflected signal. At last, the ESA extracts the time interval between the reflected signal and the excitation signal with the help of Short Time Fourier Transform (STFT) that acquires the frequency band where the reflected signal is located. Experimental verifications were carried out, and two different lengths of buried metal pipes are selected to verify the feasibility of the proposed method. The experimental results indicate that the proposed method can accurately extract the length of buried metal pipes. The superiority of the proposed method over the traditional methods, such as Peak-Peak Discriminance (PPD) and Phase Analysis Method (PAM), is demonstrated by experimental comparative studies.


Sensors ◽  
2017 ◽  
Vol 17 (3) ◽  
pp. 444 ◽  
Author(s):  
Mingzhang Luo ◽  
Weijie Li ◽  
Bo Wang ◽  
Qingqing Fu ◽  
Gangbing Song

Measurement ◽  
2018 ◽  
Vol 122 ◽  
pp. 563-572 ◽  
Author(s):  
Ming Lei ◽  
Weijie Li ◽  
Mingzhang Luo ◽  
Gangbing Song

2020 ◽  
Vol 10 (10) ◽  
pp. 3486 ◽  
Author(s):  
Panpan Gong ◽  
Mingzhang Luo ◽  
Luoyu Zhou ◽  
Liming Jiang ◽  
Xuemin Chen

The stress wave reflection method is widely used in the detection of structure size and integrity due to its advantages of low environmental impact and convenience. The detection accuracy depends on the accurate extraction of the stress wave reflection period. The traditional peak–peak method (PPM) measures the time interval between the first two peaks of the reflected waves to extract the reflection period. However, human interpretation is not avoidable for identifying the weak peak due to signal energy leaks into the surrounding environment. This paper proposes an algorithm for automatic extraction of the stress wave reflection period based on image processing to avoid human interference. The image is the short-time Fourier transform (STFT) spectrogram of the reflected wave signal after applying wavelet denoising and quadratic self-correlation operations. The edge detection method of image processing is used to extract the periodically occurring trough in the image. Graying and filtering are performed to eliminate interference. The frequency of the trough distribution is calculated by using the fast Fourier transform (FFT), and then the reflection period of the stress wave is obtained. The effectiveness and accuracy of the proposed method are validated by measuring the different lengths of two buried metal piles in soil. Comparing with the existing method of extracting the stress wave reflection period, this new algorithm comprehensively utilizes the time–frequency domain information of the stress wave reflection signal.


2011 ◽  
Vol 128-129 ◽  
pp. 525-529
Author(s):  
Qiang Gao ◽  
Xin Wei ◽  
Zhen Nan Wang ◽  
Dan Tong Na

An imaging processing method for the linear array antenna ISAR (LAA ISAR) was concerned in this paper. Range-Doppler algorithm was adopted to realize the image of each echo first; then the cross-correlation method was used for rough registration. On the basis of it, the method based on image entropy was used for precise registration. Simulations based on this method showed that the image registration was realized finely, and the target resolution was enhanced effectively.


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