Biological Acoustic Microscopy - Living Cells at 37°C and Fixed Cells in Cryogenic Liquids

1982 ◽  
Vol 40 ◽  
pp. 174-177
Author(s):  
J.A. Hildebrand ◽  
D. Rugar ◽  
C.F. Quate
Keyword(s):  
High Frequency ◽  
Acoustic Microscopy ◽  
Single Element ◽  
Acoustic Image ◽  
Acoustic Reflection ◽  
Glass Substrates ◽  
Acoustic Images ◽  
Cryogenic Liquids ◽  
Chick Heart ◽  
Coupling Medium

The scanning reflection acoustic microscope uses high frequency sound to create images with sub-micron resolution. A single-element sapphire lens focuses sound to a diffraction-limited spot in a liquid coupling medium. With the object placed near the focus, the spot of sound is mechanically scanned while the magnitude of the acoustic reflection is recorded for each point on the object. The resulting acoustic image is bright in areas of large acoustic reflection and dark in areas of small acoustic reflection. Acoustic images of biological cells contain information on cellular viscous, elastic and topographic properties. This paper presents acoustic images of living and fixed chick heart fibroblasts grown on glass substrates.

scholarly journals Underwater Acoustic Image Denoising Using Stationary Wavelet Transform and Various Shrinkage Functions

2021 ◽  
Vol 20 (2) ◽  
Author(s):  
Priyadharsini Ravisankar
Keyword(s):  
Wavelet Transform ◽  
Image Denoising ◽  
High Frequency ◽  
Low Frequency ◽  
Stationary Wavelet Transform ◽  
Acoustic Image ◽  
Underwater Acoustic ◽  
Acoustic Images ◽  
Frequency Components ◽  
Shrinkage Functions

Underwater acoustic images are captured by sonar technology which uses sound as a source. The noise in the acoustic images may occur only during acquisition. These noises may be multiplicative in nature and cause serious effects on the images affecting their visual quality. Generally image denoising techniques that remove the noise from the images can use linear and non-linear filters. In this paper, wavelet based denoising method is used to reduce the noise from the images. The image is decomposed using Stationary Wavelet Transform (SWT) into low and high frequency components. The various shrinkage functions such as Visushrink and Sureshrink are used for selecting the threshold to remove the undesirable signals in the low frequency component. The high frequency components such as edges and corners are retained. Then the inverse SWT is used for reconstruction of denoised image by combining the modified low frequency components with the high frequency components. The performance measure Peak Signal to Noise Ratio (PSNR) is obtained for various wavelets such as Haar, Daubechies,Coiflet and by changing the thresholding methods.

Practical Design of a High Frequency Phased-Array Acoustic Microscope Probe: A Preliminary Study

2017 ◽  
Author(s):  
Jeong Nyeon Kim ◽  
Richard L. Tutwiler ◽  
Judith A. Todd
Keyword(s):  
High Frequency ◽  
Phased Array ◽  
Incident Angle ◽  
Focal Length ◽  
Acoustic Microscopy ◽  
Mode Shapes ◽  
Single Element ◽  
Acoustic Microscope ◽  
Acoustic Lens ◽  
Microscope Probe

Scanning acoustic microscopy (SAM) has been a well-recognized tool for both visualization and quantitative evaluation of materials at the microscale since its invention in 1974. While there have been multiple advances in SAM over the past four decades, some issues still remain to be addressed. First, the measurement speed is limited by the mechanical movement of the acoustic lens. Second, a single element transducer acoustic lens only delivers a predetermined beam pattern for a fixed focal length and incident angle, thereby limiting control of the inspection beam. Here, we propose to develop a phased-array probe as an alternative to overcome these issues. Preliminary studies to design a practical high frequency phased-array acoustic microscope probe were explored. A linear phased-array, comprising 32 elements and operating at 5 MHz, was modeled using PZFlex, a finite-element method software. This phased-array system was characterized in terms of electrical input impedance response, pulse-echo and impulse response, surface displacement profiles, mode shapes, and beam profiles. The results are presented in this paper.

Study of the elastic properties of sprayed SnO2 and SnS2 layers

2000 ◽  
Vol 77 (9) ◽  
pp. 705-715
Author(s):  
M Mnari ◽  
B Cros ◽  
M Amlouk ◽  
S Belgacem ◽  
D Barjon
Keyword(s):  
High Frequency ◽  
Chemical Structure ◽  
Spray Pyrolysis Technique ◽  
Acoustic Microscopy ◽  
Acoustic Parameters ◽  
Force Microscopy ◽  
Photovoltaic Application ◽  
Atomic Force ◽  
Acoustic Signature ◽  
Acoustic Images

SnO2 and SnS2 thin films have been prepared by the spray pyrolysis technique for photovoltaic application purposes and characterized by high-frequency acoustic microscopy (570 MHz).The surface acoustic images reveal contrasts explained by differences in topography according to atomic force microscopy studies. The acoustic signature V(z) of the systemslayer/substrate were modelled and refined to fit with the experimental V(z). The acoustic parameters of the layers were calculated using the results of the final simulation. The values of Young's modulus deduced from the acoustic parameters, 401 and 56 GPa for SnO2 and SnS2, respectively, are discussed in relation with the chemical structure and bonding involved. PACS Nos.: 43.35Ns and 62.65

scholarly journals Use of Ultrasound Microscopy for Ex Vivo Analysis of Acoustic Impedance in Mouse Liver with Steatohepatitis

Acoustics ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 3-10
Author(s):  
Hideki Kumagai ◽  
Kazuto Kobayashi ◽  
Sachiko Yoshida ◽  
Koji Yokoyama ◽  
Norio Hirota ◽  
...  
Keyword(s):  
Acoustic Impedance ◽  
Ex Vivo ◽  
Acoustic Microscopy ◽  
Control Group ◽  
Scanning Acoustic Microscopy ◽  
Central Frequency ◽  
Deficient Diet ◽  
Acoustic Images ◽  
Ultrasound Microscopy

Scanning acoustic microscopy reveals information on histology and acoustic impedance through tissues. The objective of the present study was to investigate whether acoustic impedance values in the liver over time reflect the progression of steatohepatitis through different grades and stages, and whether this approach can visualize histologic features of the disease. Mice were divided into two groups: a control group and a steatohepatitis group prepared by keeping the mice on a methionine and choline-deficient diet for 56 weeks. The hepatic lobe was excised for measurement of impedance and observation of microscopic structure using a commercially available scanning acoustic microscopy system with a central frequency of 320 MHz. Scanning acoustic microscopy revealed that acoustic impedance through liver tissue with steatohepatitis temporarily decreased with the degree of fat deposition and then increased in parallel with the progression of inflammation and fibrosis. However, the acoustic images obtained did not allow discrimination of detailed microstructures from those seen using light microscopy. In conclusion, estimation of acoustic impedance appears to have potential clinical applications, such as for monitoring or follow-up studies.

Design, fabrication, and evaluation of high frequency, single-element transducers incorporating different materials

2002 ◽  
Vol 49 (2) ◽  
pp. 169-176 ◽  
Author(s):  
K.A. Snook ◽  
Jian-Zhong Zhao ◽  
C.H.F. Alves ◽  
J.M. Cannata ◽  
Wo-Hsing Chen ◽  
...  
Keyword(s):  
High Frequency ◽  
Single Element

scholarly journals Synthetic Aperture Imaging Using High-Frequency Convex Array for Ophthalmic Ultrasound Applications

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2275
Author(s):  
Hae Gyun Lim ◽  
Hyung Ham Kim ◽  
Changhan Yoon
Keyword(s):  
Image Quality ◽  
Penetration Depth ◽  
Spatial Resolution ◽  
High Frequency ◽  
Imaging System ◽  
Ex Vivo ◽  
Synthetic Aperture ◽  
Single Element ◽  
High Frequency Ultrasound ◽  
Synthetic Aperture Imaging

High-frequency ultrasound (HFUS) imaging has emerged as an essential tool for pre-clinical studies and clinical applications such as ophthalmic and dermatologic imaging. HFUS imaging systems based on array transducers capable of dynamic receive focusing have considerably improved the image quality in terms of spatial resolution and signal-to-noise ratio (SNR) compared to those by the single-element transducer-based one. However, the array system still suffers from low spatial resolution and SNR in out-of-focus regions, resulting in a blurred image and a limited penetration depth. In this paper, we present synthetic aperture imaging with a virtual source (SA-VS) for an ophthalmic application using a high-frequency convex array transducer. The performances of the SA-VS were evaluated with phantom and ex vivo experiments in comparison with the conventional dynamic receive focusing method. Pre-beamformed radio-frequency (RF) data from phantoms and excised bovine eye were acquired using a custom-built 64-channel imaging system. In the phantom experiments, the SA-VS method showed improved lateral resolution (>10%) and sidelobe level (>4.4 dB) compared to those by the conventional method. The SNR was also improved, resulting in an increased penetration depth: 16 mm and 23 mm for the conventional and SA-VS methods, respectively. Ex vivo images with the SA-VS showed improved image quality at the entire depth and visualized structures that were obscured by noise in conventional imaging.

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