Journal: IEEE transactions on ultrasonics, ferroelectrics, and frequency control

Article Title: Fast Local Phase Velocity Based Imaging (LPVI): Shear Wave Particle Velocity and Displacement Motion Study

doi: 10.1109/TUFFC.2019.2948512

Figure Lengend Snippet: Computation time (a) for reconstruction of a final 2-D shear wave phase velocity map based on the LR and RL waves, for the original implementation of the LPVI method proposed in [22] (green and blue curves) and the modified, new approach proposed in this manuscript (red curve). Original 1 stands for adopting a built-in fft2(·) function in MATLAB whereas, Original 2 represents data for using dual fft(·) functions, respectively. Peak memory requirements, for all implementations, is marked as a dashed, square line in (b). Results are presented against number of DOFs corresponding to the number of pixels present in the spatial wavefield data (z and x). Calculations were performed on a standalone computer equipped with Windows 7 Professional operating system and the Intel(R) Xeon(R) CPU E5–2683 v4 @2.10 GHz processor. Padding factor of 1024 was used in the directions z and x, as well as, in the time domain.

Article Snippet: The original LPVI method was studied twofold: by adopting a built-in fft2( · ) function in MATLAB (Original 1, green curve), and by using dual fft( · ) functions (Original 2, blue curve), for calculating F 2 D . Results are presented against number of degrees-of-freedom (DOFs) corresponding to the number of pixels present in a 2-D spatial wavefield data ( z and x ).

Techniques: Shear, Modification

Journal: Crystal Growth & Design

Article Title: Effect of Ultrasound Standing Wave-Induced Acoustophoresis in Monoglyceride Oleogel Structuration

doi: 10.1021/acs.cgd.5c00291

Figure Lengend Snippet: Top two rows: Bright-field optical microscopy images of 10% (S10#) and 5% (S5#) MG sonicated samples from distinct locations. Left-most column: bright-field optical microscopy images of 10% (R10#1) and 5% (R5#1) MG reference samples. Lowest row: Power spectra plots for 10% (left) and 5% (right) MG samples, respectively.

Article Snippet: The image processing consisted of five steps: (i) microscopy images (stored as uncompressed.TIF files) were imported into MATLAB ( , step i); (ii) the complement of the imported image was taken, and a circular diffuse (Gaussian) mask was applied ( , step ii); (iii) following this, the 2D FFT operation was numerically carried out utilizing the MATLAB’ built-in fft2 () function, and the result was centrally shifted using the fftshift () function ( , step iii); (iv) sharp bandpass filters were applied once again utilizing MIMT ( , step iv), where the appropriate spatial frequency axes were calculated utilizing the spatial resolution provided by our microscope; and (v) the resulting spatial frequency space matrix was mapped to polar coordinates, with the origin at the center of the matrix ( , step v).

Techniques: Microscopy, Sonication

Journal: Crystal Growth & Design

Article Title: Effect of Ultrasound Standing Wave-Induced Acoustophoresis in Monoglyceride Oleogel Structuration

doi: 10.1021/acs.cgd.5c00291

Figure Lengend Snippet: Coded excitation scanning acoustic microscopy images for (A) 10% MG reference sample, (B) 5% MG reference sample, (C) 10% MG sonicated sample, and (D) 5% MG sonicated sample. Images are 3 × 3 mm 2 in size. The scale bar shown applies for all images (A–D).

Article Snippet: The image processing consisted of five steps: (i) microscopy images (stored as uncompressed.TIF files) were imported into MATLAB ( , step i); (ii) the complement of the imported image was taken, and a circular diffuse (Gaussian) mask was applied ( , step ii); (iii) following this, the 2D FFT operation was numerically carried out utilizing the MATLAB’ built-in fft2 () function, and the result was centrally shifted using the fftshift () function ( , step iii); (iv) sharp bandpass filters were applied once again utilizing MIMT ( , step iv), where the appropriate spatial frequency axes were calculated utilizing the spatial resolution provided by our microscope; and (v) the resulting spatial frequency space matrix was mapped to polar coordinates, with the origin at the center of the matrix ( , step v).

Techniques: Microscopy, Sonication

Journal: Scientific Reports

Article Title: Angular compounding for speckle reduction in optical coherence tomography using geometric image registration algorithm and digital focusing

doi: 10.1038/s41598-020-58454-0

Figure Lengend Snippet: Speckle reduction by angular compounding in an OCT system. ( a ) The incident angle \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha $$\end{document} α is manipulated by the offsetting distance \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$d$$\end{document} d , the distance between the lens optical axis and the galvo centerline, and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha \approx \arctan (d/f)$$\end{document} α ≈ arctan ( d / f ) . The scanning direction is along the \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$x$$\end{document} x -direction. ( b ) The detected area for a point is determined by the light wavefronts and the axial resolution. ( c ) The area rotates with the incident angle. The dark blue dots represent strong scatterers and the light blue ones are weak scatterers. ( d ) Speckle can be generated by two strong scatterers with similar scattering amplitudes. ( e , f ) Finite element analysis (FEA) simulations by COMSOL software are applied to demonstrate the feasibility of speckle-reduction, the details of which can be found in method section. The light source is 920 nm and the light spatial frequency is doubled in the figure due to the round-trip optical path. The beam is rotated by the incident angle and the optical pathlength difference between the two scatterers is modulated simultaneously, changing the total amplitude ( g ) and phase difference ( h ) of the two scatterers. The distance \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${D}_{12}$$\end{document} D 12 is 2 μm.

Article Snippet: In practice, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$F{T}_{x,z}$$\end{document} F T x , z is calculated from built-in Matlab functions, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$F{T}_{x,z}=|fftshift(fft2(CI))|$$\end{document} F T x , z = | f f t s h i f t ( f f t 2 ( C I ) ) | , here \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$fft2$$\end{document} f f t 2 is for the two-dimensional (2D) fast Fourier transform and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$fftshift$$\end{document} f f t s h i f t shifts the zero-frequency component to the center of the matrix.

Techniques: Generated, Software