【摘 要】
：
The noise produced by ultrasonic testing system,material noise and coupled noise often gives difficulty in recognition and judgment of ultrasonic signals defect.Time-frequency analysis provides ultras
【机 构】
：
Institute of Automation and Electronic Engineering,Qingdao University of Science and Technology,Qing
论文部分内容阅读
The noise produced by ultrasonic testing system,material noise and coupled noise often gives difficulty in recognition and judgment of ultrasonic signals defect.Time-frequency analysis provides ultrasonic echo denoising method,but short-time Fourier uses fixed window,and its resolution is lower.Although wavelet analysis has high resolution analysis of advantages,the signal feature information distrioutes in many coefficients of the decomposition Matching pursuit algorithm according to the signal features adaptive selection function outspread linear of signal for less signal of atoms,so as to realize the noise suppression.In the processing of ultrasonic signal,we use chirplet atom which has the same structure to match the ultrasonic signals echo information effectively.Finally,through the simulation we use matching tracking method to deal with the noise,and compared to wavelet de-noising results.The results show using the method can get a good signal to noise ratio.
其他文献
Time series have included a series of data materials.These data masteries are the data that is acquired through the passing of the time or the increase of the other variables.Our world is not immutabl
Pedestrian traffic becomes a pivotal part in large cities,but also leads to many conflicts.In order to grasp the traffic characteristics of pedestrians and provide the basis for pedestrian traffic org
With a computer-aided simulation method,this study analyzes the energy cost per 10,000 passenger-kilometers of the transports completed by High-Speed Railway(HSR)trains with various target speeds on c
Shortwave communication is an important military communication way.Cognitive radio is the best way to solve the problem of shortwave resource shortage and its low use rate.In this paper,3 military sho
A High Definition video decoder for use with the Subway Vehicle Passenger Information System has been designed in the paper.Huge burden has been placed on CPU due to the massive amount of data in 1080
Passenger train plan is an important part of transport organization work.It is the core problem that how to develop a reasonable passenger train plan.For the specific operating conditions MAFN combine
From view point of complex network,this paper carries out a thorough analysis of mobile Ad hoc network architecture in four terms of node,structure,topology control and protocol stack expansion of Ad
Aiming at complex geological conditions and hydrological conditions slope deformation,monitoring system applied research was done.The slope was done real-time monitor with the methods of slope rock mo
In order to achieve the automatic monitoring of roadway roof abscission layer,timely and accurate grasp of the dynamic changes of roadway roof abscission layer,will face the roof abscission layer in a
This paper descnibes the technology of wideband digital downconverter(WDDC)for synthetic instruments(Sis).DDCs first mix the wideband signal with the local frequency generated by numerically controlle