The success of ultrasonic nondestructive testing technology depends not only on the generation and measurement of the desired waveform, but also on the signal processing of the measured waves. The traditional time-dom...The success of ultrasonic nondestructive testing technology depends not only on the generation and measurement of the desired waveform, but also on the signal processing of the measured waves. The traditional time-domain methods have been partly successful in identifying small cracks, but not so successful in estimating crack size, especially in strong backscattering noise. Sparse signal representation can provide sparse information that represents the signal time-frequency signature, which can also be used in processing ultrasonic nondestructive signals. A novel ultrasonic nondestructive signal processing algorithm based on signal sparse representation is proposed. In order to suppress noise, matching pursuit algorithm with Gabor dictionary is selected as the signal decomposition method. Precise echoes information, such as crack location and size, can be estimated by quantitative analysis with Gabor atom. To verify the performance, the proposed algorithm is applied to computer simulation signal and experimental ultrasonic signals which represent multiple backscattered echoes from a thin metal plate with artificial holes. The results show that this algorithm not only has an excellent performance even when dealing with signals in the presence of strong noise, but also is successful in estimating crack location and size. Moreover, the algorithm can be applied to data compression of ultrasonic nondestructive signal.展开更多
针对传统的混凝土检测系统检测精度低、成本高、信号处理能力差的缺点,提出了一种一发四收超声信号处理系统。该系统选用200 k Hz的超声,以合成孔径聚焦成像算法为基础,将四路信号整合为一路信号,通过判断回波信号声时、声幅和主频的变...针对传统的混凝土检测系统检测精度低、成本高、信号处理能力差的缺点,提出了一种一发四收超声信号处理系统。该系统选用200 k Hz的超声,以合成孔径聚焦成像算法为基础,将四路信号整合为一路信号,通过判断回波信号声时、声幅和主频的变化来对混凝土质量进行检测,大大增加了混凝土缺陷回波的分辨率,提高了系统的检测精度。实验表明,系统性能稳定,精度高,有广阔的应用前景。展开更多
基金supported by National Natural Science Foundation of China (Grant No. 60672108, Grant No. 60372020)
文摘The success of ultrasonic nondestructive testing technology depends not only on the generation and measurement of the desired waveform, but also on the signal processing of the measured waves. The traditional time-domain methods have been partly successful in identifying small cracks, but not so successful in estimating crack size, especially in strong backscattering noise. Sparse signal representation can provide sparse information that represents the signal time-frequency signature, which can also be used in processing ultrasonic nondestructive signals. A novel ultrasonic nondestructive signal processing algorithm based on signal sparse representation is proposed. In order to suppress noise, matching pursuit algorithm with Gabor dictionary is selected as the signal decomposition method. Precise echoes information, such as crack location and size, can be estimated by quantitative analysis with Gabor atom. To verify the performance, the proposed algorithm is applied to computer simulation signal and experimental ultrasonic signals which represent multiple backscattered echoes from a thin metal plate with artificial holes. The results show that this algorithm not only has an excellent performance even when dealing with signals in the presence of strong noise, but also is successful in estimating crack location and size. Moreover, the algorithm can be applied to data compression of ultrasonic nondestructive signal.
文摘针对传统的混凝土检测系统检测精度低、成本高、信号处理能力差的缺点,提出了一种一发四收超声信号处理系统。该系统选用200 k Hz的超声,以合成孔径聚焦成像算法为基础,将四路信号整合为一路信号,通过判断回波信号声时、声幅和主频的变化来对混凝土质量进行检测,大大增加了混凝土缺陷回波的分辨率,提高了系统的检测精度。实验表明,系统性能稳定,精度高,有广阔的应用前景。
