Phase retrieval in digital speckle pattern interferometry using a chirped Gaussian wavelet transform and a smoothed time-frequency distribution

2003 ◽  
Author(s):  
Alejandro Federico ◽  
Guillermo H. Kaufmann
Keyword(s):  
Wavelet Transform ◽  
Frequency Distribution ◽  
Phase Retrieval ◽  
Speckle Pattern ◽  
Time Frequency ◽  
Digital Speckle Pattern Interferometry ◽  
Digital Speckle ◽  
Time Frequency Distribution

Simultaneous Measurement of In-Plane and Out-of-Plane Deformations Using Dual-Beam Spatial-Carrier Digital Speckle Pattern Interferometry

2015 ◽  
Vol 782 ◽  
pp. 316-325 ◽  
Author(s):  
Kai Liu ◽  
Si Jin Wu ◽  
Xin Ya Gao ◽  
Lian Xiang Yang
Keyword(s):  
High Speed ◽  
Phase Retrieval ◽  
Speckle Pattern ◽  
High Tech ◽  
Advanced Technique ◽  
Digital Speckle Pattern Interferometry ◽  
Dual Beam ◽  
Out Of Plane ◽  
Digital Speckle ◽  
Plane Deformations

Digital speckle pattern interferometry (DSPI) is an advanced technique for both in-plane and out-of-plane deformation measurements of diffuse surfaces in nanoscale. It has been widely used in aerospace engineering and other high-tech industries due to the advantages of non-contact, high-accuracy and full-field measurement. Traditionally, DSPI uses temporal phase shifting method to achieve precise deformation measurement, but it is only suitable for quasi-static deformation. Spatial-carrier method is another effective phase retrieval method used in DSPI and its validity has been verified in some DSPI setups. DSPI with spatial-carrier method enjoys the advantages of simple optical arrangement, easy operation, and above all, high-speed measurement of deformation. This paper introduces a dual-beam spatial-carrier digital speckle pattern interferometry system, with which in-plane and out-of-plane deformations can be measured simultaneously as well as quickly. In the optical setup, two lasers are employed to illuminate the measured object with different illumination angles, and two single-mode fibers server as carriers to transmit the reference beams. In-plane and out-of-plane deformations can be obtained by combining the phase maps of both channels. Theoretical discussion and experimental analysis are both presented.

Extension of Traditional Frequency and Research on Time-Frequency Distribution

2010 ◽  
Vol 44-47 ◽  
pp. 2089-2093
Author(s):  
Shu Lin Liu ◽  
Xian Ming Wang ◽  
Hui Wang ◽  
Hai Feng Zhao
Keyword(s):  
Wavelet Transform ◽  
Frequency Distribution ◽  
Frequency Analysis ◽  
Physical Meaning ◽  
The Novel ◽  
Analysis Method ◽  
Hilbert Huang Transform ◽  
Time Frequency ◽  
Novel Approach ◽  
Time Frequency Distribution

The concept of traditional frequency is extended and the concept of local frequency is proposed, which makes the physical meaning of frequency clearer. The wide adaptability of local frequency is also discussed. Moreover, a novel time-frequency analysis method is presented based on local frequency. The time-frequency distribution of continuous triangular wave signal is analyzed by the novel approach. Compared with wavelet transform and Hilbert-Huang transform (HHT), the results show that the concept of local frequency is correct and the novel time-frequency approach is effective.

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