Flaw detection and sizing of ultrasonic images using wavelet transform and SAFT

Author(s):  
Ren-Jean Liou ◽  
Kuang-Chien Kao ◽  
Chin-Yung Yeh ◽  
Mu-Sung Chen
Author(s):  
Luka Posilovic ◽  
Duje Medak ◽  
Marko Subasic ◽  
Tomislav Petkovic ◽  
Marko Budimir ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
pp. 216-222
Author(s):  
Guiping Zhang ◽  
Lili Zhou ◽  
Xiao Zhang ◽  
Xiaoli Gao ◽  
Lingling Li

In order to improve the treatment accuracy of patients with different subtypes of bladder prolapse (BP), the value of ultrasonic images based on fuzzy theory (FT) and wavelet transform (WT) algorithm for detection and classification of subtypes of BP was discussed. First, the effects of fuzzy enhancement (FE) algorithm, WT enhancement algorithm, and FT combined wavelet algorithm on medical ultrasonic images were compared. Then, 144 cases of BP patients admitted to our hospital from October 2017 to October 2019 were selected as study objects. Ultrasound technology was used to examine the patient's bottom information. Finally, the data of posterior urethra-vesical angle (PUVA), rotation angle (RA) of urethra, mobility of bladder neck, lowest point of bladder and lowest point of posterior wall of bladder were measured under resting and Vslsalva conditions. According to Green classification, different subtypes of bladder prolapse were distinguished by the measurement data of pelvic floor (PF) ultrasound image. The clinical characteristics of Stress Urinary Incontinence (SUI), dysuria, and frequent urination of subtypes of BP were compared. The results showed that the ultrasonic image quality was the best by combining FT with WT; BP type II PUVA was more than 140°, BP type III PUVA was less than 140°, and the difference between the two was statistically significant (P < 0.05); the lowest point of the bladder in patients with type III BP was significantly higher than that in patients with type II BP (P < 0.05), and the neck mobility of type III bladder and the lowest point of the posterior wall of the bladder were significantly lower than that in patients with type II BP (P < 0.05); the difference of urethral RA between type II and type III of BP was not statistically significant (P > 0.05); the incidence of SUI in patients with type II BP was higher than that of type III BP (P < 0.05), and the incidence of dysuria in patients with type III BP was higher than that of type II BP (P < 0.05); the incidence of urinary frequency in patients with type II and type III BP was not statistically significant (P > 0.05), which showed that PF ultrasound based on FT and WT algorithm could effectively detect and identify different subtypes of BP.


2011 ◽  
Vol 31 (2) ◽  
pp. 108-116 ◽  
Author(s):  
Ahmed Kechida ◽  
Redouane Drai ◽  
Abderrezak Guessoum

2007 ◽  
Vol 347 ◽  
pp. 115-120
Author(s):  
Magdalena Rucka ◽  
Krzysztof Wilde

This paper presents experimental study on dispersive waves propagation in steel rails. The propagation of longitudinal and transverse waves was generated by an impulse hammer and measured in three points. Wavelet transform (WT) and short time Fourier transform (STFT) were applied to analyze the time signals. Analysis of signal by STFT does not provide a proper timefrequency representation due to a fixed size window. The wavelet transform can effectively identify the time-frequency components in waves. The wavelet signal processing of the experimental wave propagation signals is intended to be used for rail flaw detection.


2011 ◽  
Vol 383-390 ◽  
pp. 4755-4761
Author(s):  
Shao Jiang Wang ◽  
Li Hou ◽  
Yu Lin Wang ◽  
Jian Quan Zhang

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.


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