Visualization of Shear Stress With Micro Imaging Chip and Discrete Wavelet Transform

2002 ◽  
Vol 124 (4) ◽  
pp. 1018-1024 ◽  
Author(s):  
Motoaki Kimura ◽  
Masahiro Takei ◽  
Chih-Ming Ho ◽  
Yoshifuru Saito ◽  
Kiyoshi Horii
Keyword(s):  
Reynolds Number ◽  
Shear Stress ◽  
Wavelet Transform ◽  
Discrete Wavelet Transform ◽  
Wavelet Transforms ◽  
Wave Number ◽  
Discrete Wavelet ◽  
Two Dimensional ◽  
Micro Electro Mechanical Systems ◽  
Low Speed

The two-dimensional low-speed structure of a turbulent boundary layer has been clearly visualized by a combination of a shear stress sensor using micro electro mechanical systems and the discrete wavelet transform. The application of two-dimensional discrete wavelet transforms to the visualization of wall shear stress data obtained using the micro shear stress imaging chip is described. The experiment was carried out under various Reynolds number conditions. It is shown that it is possible to visualize the low-speed streak structure as contours of two-dimensional wavelet level corresponding to spanwise wave number as a function of Reynolds number.

scholarly journals The Improvement of Discrete Wavelet Transform

2021 ◽  
Author(s):  
Zhihua Zhang
Keyword(s):  
Wavelet Transform ◽  
Decay Rate ◽  
Discrete Wavelet Transform ◽  
Wavelet Transforms ◽  
Polynomial Interpolation ◽  
Discrete Wavelet ◽  
Two Dimensional ◽  
Wavelet Coefficients ◽  
Periodic Wavelet ◽  
Improved Algorithm

Discrete wavelet transform and discrete periodic wavelet transform have been widely used in image compression and data approximation. Due to discontinuity on the boundary of original data, the decay rate of the obtained wavelet coefficients is slow. In this study, we use the combination of polynomial interpolation and one-dimensional/two-dimensional discrete periodic wavelet transforms to mitigate boundary effects. The decay rate of the obtained wavelet coefficients in our improved algorithm is faster than that of traditional two-dimensional discrete wavelet transform. Moreover, our improved algorithm can be extended naturally to the higher-dimensional case.

Flexible architecture for the implementation of the two-dimensional discrete wavelet transform (2D-DWT) oriented to FPGA devices

2004 ◽  
Vol 28 (9) ◽  
pp. 509-518 ◽  
Author(s):  
Ricardo José Colom-Palero ◽  
Rafael Gadea-Girones ◽  
Francisco José Ballester-Merelo ◽  
Marcos Martı́nez-Peiro
Keyword(s):  
Wavelet Transform ◽  
Discrete Wavelet Transform ◽  
Discrete Wavelet ◽  
Two Dimensional ◽  
Flexible Architecture
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