Robust frequency diversity based algorithm for clutter noise reduction of ultrasonic signals using multiple sub-spectrum phase coherence

2014 ◽  
Author(s):  
R. Gongzhang ◽  
M. Li ◽  
B. Xiao ◽  
T. Lardner ◽  
A. Gachagan
Keyword(s):  
Noise Reduction ◽  
Phase Coherence ◽  
Frequency Diversity ◽  
Ultrasonic Signals

Noise Reduction Using Wavelet Transform in Ultrasonic Flaw Detection of Small-Diameter Steel Pipe with Thick Wall

2011 ◽  
Vol 383-390 ◽  
pp. 4755-4761
Author(s):  
Shao Jiang Wang ◽  
Li Hou ◽  
Yu Lin Wang ◽  
Jian Quan Zhang
Keyword(s):  
Wavelet Transform ◽  
Noise Reduction ◽  
Flaw Detection ◽  
Small Diameter ◽  
Internal Noise ◽  
Thick Wall ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Ultrasonic Signals ◽  
Steel Pipes

In order to ensure that small diameter steel pipes with thick wall have high intensity and high quality, ultrasonic immersion method with focusing probe was used to detect the flaw of the small-diameter steel pipes with thick wall. In practice, the echoes are often corrupted with external noise or internal noise, therefore, it is necessary to reduce the noise and to enhance the SNR of ultrasonic signals. A technique for improving the SNR of ultrasonic signals using wavelet transform is presented. In this method, WT, consider as one band-pass filter, is used to remove the noises. The performance of this technique has been verified by experimental, which is done by using a series of flaw ultrasonic echoes obtained from a specimen of the small-diameter steel pipes with thick wall. In particular we have found the processing of the ultrasonic signals using wavelet transform extremely useful for noise reduction. After processing, the SNR of ultrasonic signals are enhanced substantially. All experimental results show that this technique is effective for removing the white noise from the ultrasonic signals.

scholarly journals Signal Separation in Ultrasonic Non-Destructive Testing

10.14311/992 ◽  
2007 ◽  
Vol 47 (6) ◽  
Author(s):  
V. Matz ◽  
M. Kreidl ◽  
R. Šmíd
Keyword(s):  
Noise Reduction ◽  
Wiener Filter ◽  
Signal Separation ◽  
Material Structure ◽  
Discrete Wavelet ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Ultrasonic Signals ◽  
Signal Processing Methods ◽  
Non Destructive

In ultrasonic non-destructive testing the signals characterizing the material structure are commonly evaluated. The sensitivity and resolution of ultrasonic systems is limited by the backscattering and electronic noise level commonly contained in the acquired ultrasonic signals. For this reason, it is very important to use appropriate advanced signal processing methods for noise reduction and signal separation. This paper compares algorithms used for efficient noise reduction in ultrasonic signals in A-scan. Algorithms based on the discrete wavelet transform and the Wiener filter are considered. Part of this paper analyses and applies blind source separation, which has never been used in practical ultrasonic non-destructive testing. All proposed methods are evaluated on both simulated and acquired ultrasonic signals. 

GRAIN NOISE REDUCTION BY PHASE COHERENCE IMAGING

2010 ◽  
Author(s):  
J. Camacho ◽  
J. Brizuela ◽  
C. Fritsch ◽  
Donald O. Thompson ◽  
Dale E. Chimenti
Keyword(s):  
Noise Reduction ◽  
Phase Coherence ◽  
Coherence Imaging

Satisfaction With Noise Reduction Circuits

1993 ◽  
Vol 2 (1) ◽  
pp. 51-53 ◽  
Author(s):  
Ruth A. Bentler
Keyword(s):  
Noise Reduction

КОНЦЕПЦІЯ СТВОРЕННЯ СИЛОВОЇ УСТАНОВКИ СІМЕЙСТВА РЕГІОНАЛЬНИХ ПАСАЖИРСЬКИХ ЛІТАКІВ АН-148/АН-158

2019 ◽  
pp. 50-63
Author(s):  
О. Д. Донець ◽  
В. П. Іщук
Keyword(s):  
Power Plant ◽  
Noise Reduction ◽  
Fuel Consumption ◽  
Electronic System ◽  
Electronic Control ◽  
Level Of Automation ◽  
Auxiliary Power ◽  
Power Plant Control ◽  
Technical Status ◽  
Air Intake

The basic results of calculation and research works carried out in the process of creation of power unit of regional passenger airplanes’ family are given. The design features of the propulsion engines and engine of the auxiliary power plant are described. The aforementioned propulsion system includes propulsion engines D-436-148 and engine AI-450-MS of auxiliary power plant. In order to comply with the requirements of Section 4 of the ICAO standard (noise reduction of the aircraft in site), in part of ensuring the noise reduction of engines, when creating the power plant of the An-148/An-158 aircraft family, a single- and double-layer acoustic filler was used in the structure of the engine nacelle and air intake. The use of electronic system for automatic control of propulsion engines such as FADEC and its integration into the digital airborne aircraft complex ensured the operation of engines, included in the power plant provided with high specific fuel consumption, as well as increased the level of automation of the power plant control and monitoring, and ensured aircraft automation landing in ICAO category 3A. In addition, the use of the aforementioned electronic system, allowed to operate the power plant of the aircraft in accordance with technical status. The use of the AI-450-MS auxiliary power plant with an electronic control system such as FADEC, and the drive of the service compressor from a free turbine, eliminated the effect of changes in power and air takeoff, on the deviation of the engine from optimal mode, which also minimized the fuel consumption. The use of fuel metering system TIS-158, allowed to ensure control of its condition and assemblies, without the use of auxiliary devices, built-in control means. In the fire protection system, the use of the electronic control and monitor unit, as well as the use of digital serial code for the exchange of information between the elements of the system and the aircraft systems, has reduced the number of connections, which increased the reliability of the system and reduced its weight characteristics.

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