Optical Computerized Tomography for Visualization of Ultrasonic Fields Using Michelson Interferometer

Obuchi, Takeshi; Masuyama, Hiroyuki; Mizutani, Koichi; Nakanishi, Satoshi

doi:10.1143/jjap.45.7152

Cited by 15 publications

(20 citation statements)

References 21 publications

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“…6) Then, sound field at z = z 2 is calculated from the measured sound field at z = z 1 using applied NAH with an initially set sound velocity distribution. Difference between calculated and measured sound fields at z = z 2 is minimized by optimizing the sound velocity distribution.…”

Section: Principles Of Temperature Estimationmentioning

confidence: 99%

Temperature Distribution Estimated by Optimization and Near-Field Acoustical Holography

et al. 2012

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We propose a method to estimate temperature distribution non-destructively using combination of near-field acoustical holography (NAH) method and optimization method. NAH method is valid to calculate forward and back propagations of ultrasonic wave in a uniform medium. To estimate of temperature distribution, we proposed a modified method of NAH, called sectional NAH (SNAH), for using NAH in an inhomogeneous medium. In SNAH, a calculation space is discretized into a number of sections, so that the temperature in each section becomes nearly uniform, and NAH calculation is performed in each section. Calculation results using SNAH in the inhomogeneous medium well agreed with the calculation result using finite element method (FEM). By using SNAH, the temperature distribution is estimated as bellows. Firstly, sound fields, which are complex amplitude of harmonic oscillation, in three planes are measured. Next, sound field at one of measured plane is calculated from the other measured sound fields, which are calculated from other measurement planes using SNAH, with an initial sound velocity distribution. Then, difference between calculated and measured sound fields is minimized by optimizing the sound velocity distribution using multi-start downhill simplex method. In this method, a temperature distribution is obtained as the sound velocity distribution. In simulations, temperature distributions given as linear and Gaussian distributions were estimated. Validity of our proposal methods is confirmed by simulations.

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Section: Principles Of Temperature Estimationmentioning

confidence: 99%

Temperature Distribution Estimated by Optimization and Near-Field Acoustical Holography

et al. 2012

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“…The signals are projection data of the real and imaginary part of the complex sound pressure amplitude, respectively. Thus, some projections are obtained with rotation scannings, and the radiated sound field is reconstructed from projections using CT method [3].…”

Section: Principle Of Measurement 21 Reconstruction Of the Sound Fieldsmentioning

confidence: 99%

“…For measuring the temperature with obstacles on the sound beam axis, we propose two methods. Firstly, to measure the sound wave, we use an optical probe [3]. To measure the sound wave with the optical probe, a refractive index fluctuation by the sound wave is utilized.…”

Section: Introductionmentioning

confidence: 99%

Measurement of Sound Velocity in Water Using Optical Probe and Acoustical Holography

Ohbuchi

Mizutani

Wakatsuki³

et al. 2008

The Journal of the Acoustical Society of America

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We propose a method for determining a sound velocity in three-dimensional space with obstacles using a Michelson interferometer, optical computerized tomography (O-CT) and near-field acoustical holography (NAH). Ultrasonic waves affect the phase of a test light passing through the radiated sound fields. Zeroth-order diffraction light including sound pressure information is electrically acquired by an avalanche photodiode (APD). Projection data along the optical axis is obtained by single linear scannings in the range of ±20 mm and electronically quadrature-detected as complex amplitude signal. Eighteen projections are acquired in the range of 0 ≤ θ < π rad, and the complex sound fields are reconstructed in a region of 28 × 28 mm 2 by O-CT. Then another plane separated by 5 mm is propagated using NAH from the acquired sound fields, and the same plane is reconstructed. Comparing the phase of the reconstructed and propagated sound fields in wave number domain, we determine the sound velocity in a region of 28 × 28 × 5 mm 3. The experimental results are in agreement with a reference value.

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“…4,5) An interferometer has been adopted to measure a two-dimensional ultrasound field using computerized tomography. [6][7][8] Visualization methods for phase objects, such as the schlieren method, [9][10][11][12] shadowgraph method, 13,14) and optical phase contrast method, 15) were used to measure ultrasound.…”

Section: Introductionmentioning

confidence: 99%

Measurement of pressure amplitude of ultrasonic standing wave based on method of obtaining optical wavefront using phase retrieval

Kuroyama

Mizutani

Wakatsuki

et al. 2014

Jpn. J. Appl. Phys.

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A method for measuring the pressure amplitude of one-dimensional standing ultrasound was proposed. An optical wavefront of a laser beam introduced parallel to the ultrasound wavefront was measured by a Fourier iterative phase retrieval method. The optical wavefront was fitted by a power series and the pressure amplitude of the standing ultrasound was calculated from the firstand second-order terms of the power series. To confirm the validity of the proposed method, an experimental verification was performed with 47 kHz standing ultrasound established in a glass cell with dimensions of 50 ' 50 ' 160 mm 3 . The pressure amplitude measured by the proposed method was compared with that measured using a hydrophone. It was confirmed that the pressure amplitudes measured by the proposed method and using the hydrophone showed the same trend. The viability of pressure amplitude measurement in ultrasound using the proposed method was established.

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Optical Computerized Tomography for Visualization of Ultrasonic Fields Using Michelson Interferometer

Cited by 15 publications

References 21 publications

Temperature Distribution Estimated by Optimization and Near-Field Acoustical Holography

Temperature Distribution Estimated by Optimization and Near-Field Acoustical Holography

Measurement of Sound Velocity in Water Using Optical Probe and Acoustical Holography

Measurement of pressure amplitude of ultrasonic standing wave based on method of obtaining optical wavefront using phase retrieval

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