Single image orthogonal fringe technique for resolution enhancement of the Fourier transform fringe analysis method

2013 ◽  
Vol 290 ◽  
pp. 33-36 ◽  
Author(s):  
Paulo J. Tavares ◽  
Mário A.P. Vaz
Keyword(s):  
Fourier Transform ◽  
Resolution Enhancement ◽  
Analysis Method ◽  
Single Image ◽  
Fringe Analysis ◽  
The Fourier Transform

Coordinate-transform technique for closed-fringe analysis by the Fourier-transform method

2001 ◽  
Vol 40 (10) ◽  
pp. 1649 ◽  
Author(s):  
Zongtao Ge ◽  
Fumio Kobayashi ◽  
Shinichi Matsuda ◽  
Mitsuo Takeda
Keyword(s):  
Fourier Transform ◽  
Fringe Analysis ◽  
Transform Method ◽  
Fourier Transform Method ◽  
The Fourier Transform ◽  
Coordinate Transform

Study on Woven Fabric Texture Based on Fourier Transform and Gabor Transform

2015 ◽  
Vol 671 ◽  
pp. 369-377 ◽  
Author(s):  
Li Qing Li ◽  
Ting Ting Shan ◽  
Le Xue ◽  
Jun Wang ◽  
Xia Chen
Keyword(s):  
Fourier Transform ◽  
Texture Analysis ◽  
Gabor Filter ◽  
Image Resolution ◽  
Woven Fabric ◽  
Gabor Transform ◽  
Analysis Method ◽  
Transform Method ◽  
Enhancement Method ◽  
The Fourier Transform

Woven fabric texture was periodic and complex, the woven fabric texture analysis method was based on Fourier transform and Gabor transform. Firstly the frequency range of woven fabric texture was obtained by using the Fourier Transform method, and the influence on fabric frequency of image resolution and fabric density was analyzed. Then the main parameters of Gabor filter was confirmed by the woven fabric texture frequency, and the sub-images which contain different texture information were obtained after the woven fabric images were decomposed and fused in different scales and directions using the Gabor filters. Finally the main texture enhancement method, the main texture elimination method, the direntional texture analysis method and extraessential texture enhancement method were discussed. The experiment proved that this method would be a powerful tool in the application of texture analysis.

scholarly journals Strain Sensitivity Enhancement of Broadband Ultrasonic Signals in Plates Using Spectral Phase Filtering

2021 ◽  
Vol 11 (6) ◽  
pp. 2582
Author(s):  
Lucas M. Martinho ◽  
Alan C. Kubrusly ◽  
Nicolás Pérez ◽  
Jean Pierre von der Weid
Keyword(s):  
Fourier Transform ◽  
Guided Waves ◽  
Strain Level ◽  
Energy Concentration ◽  
Short Time Fourier Transform ◽  
Time Frequency ◽  
Frequency Representation ◽  
The Fourier Transform ◽  
Short Time ◽  
Sensitivity Gain

The focused signal obtained by the time-reversal or the cross-correlation techniques of ultrasonic guided waves in plates changes when the medium is subject to strain, which can be used to monitor the medium strain level. In this paper, the sensitivity to strain of cross-correlated signals is enhanced by a post-processing filtering procedure aiming to preserve only strain-sensitive spectrum components. Two different strategies were adopted, based on the phase of either the Fourier transform or the short-time Fourier transform. Both use prior knowledge of the system impulse response at some strain level. The technique was evaluated in an aluminum plate, effectively providing up to twice higher sensitivity to strain. The sensitivity increase depends on a phase threshold parameter used in the filtering process. Its performance was assessed based on the sensitivity gain, the loss of energy concentration capability, and the value of the foreknown strain. Signals synthesized with the time–frequency representation, through the short-time Fourier transform, provided a better tradeoff between sensitivity gain and loss of energy concentration.

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