The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
Shinichi Takeuchi - One of the best experts on this subject based on the ideXlab platform.
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Development of Novel Tough Hydrophone with Sensor Head with Hydrothermally PZT Film Deposited on The Back Surface of Titanium Conical Front Plate
2019 IEEE International Ultrasonics Symposium (IUS), 2019Co-Authors: Fujimaru Kaise, Nagaya Okada, Michihisa Shiiba, Minoru Kurosawa, Morishita Takeshi, Shinichi TakeuchiAbstract:We had developed a tough Hydrophone using a titanium front plate and hydrothermally synthesized PZT polycrystalline film. Currently, there are two kinds of Hydrophones we are developing, one is a tough Hydrophone with a cylindrical front plate, and the other is a tough Hydrophone with a conical front plate. These two kinds of Hydrophones are not decreased their sensitivity even if they are exposed to a sound field with acoustic cavitation in the ultrasound cleaner for a total of 50 hours. However, there are differences in the scratches on the surface of the front plate. In this study, we observed the behavior of acoustic cavitation bubbles around the tip of the Hydrophone using a high-speed video camera and a laser light sheet. In the tough Hydrophone with a cylindrical front plate, a cavitation bubble cloud has been adhered to the tip of the Hydrophone from the beginning of observation. On the other hand, even with a tough Hydrophone with a conical front plate, a cavitation bubble cloud was adhered to the tip of the Hydrophone at the beginning of observation. However, when the adhered cavitation bubble cloud collided with another cavitation bubble cloud, we were able to observe behavior the adhered cavitation bubble cloud flows along the shape of the tip of the Hydrophone.
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Developing of tough Hydrophone for high intensity acoustic field at low frequency
2016 IEEE International Ultrasonics Symposium (IUS), 2016Co-Authors: Nagaya Okada, Michihisa Shiiba, Shinichi TakeuchiAbstract:Novel tough Hydrophones were developed by the depositing hydrothermally synthesized lead zirconate titanate thick film on the back-side surface of titanium plate to protect from acoustic cavitation. This Hydrophone was resistant to damage at a high-intensity acoustic field generated by a high-intensity focused ultrasound (HIFU) transducer. Since the generation of acoustic bubbles cannot be avoided at high-intensity ultrasound field, an influence of the tough Hydrophone's shape on the spatial distribution of acoustic bubbles around the Hydrophone tip was investigated for accurate and precise evaluation of acoustic fields. As the result of the visualization by particle image velocimetry (PIV) system and finite-element method (FEM) simulation, the measurements of sound fields was not affected by the influence of the Hydrophone with flat-shape tip with 3.5 mm in diameter lower than a hundred and some dozens of kHz. On the other hand, the influence of the tough Hydrophone with flat-shape tip was strongly affected located at focal point of the 1.6 MHz HIFU transducer. Indeed, the trapped acoustic bubbles derived from the standing wave were observed even if the Hydrophone has the needle-shape tip.
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Development of anti-cavitation Hydrophone with hydrothermal PZT film
2015 IEEE International Ultrasonics Symposium (IUS), 2015Co-Authors: Michihisa Shiiba, Nagaya Okada, Minoru K. Kurosawa, Shinichi TakeuchiAbstract:Novel anti-cavitation Hydrophones were fabricated by depositing a hydrothermally synthesized lead zirconate titanate polycrystalline thick film on the back of a titanium plate. We could observe that output waveform from our new type anti-cavitation Hydrophone was similar with the output waveform from the commercial anti-high acoustic pressure Hydrophone at focal point on focused ultrasound field by the ultrasound diagnostic equipment. A durability test on our fabricated anti-cavitation Hydrophone was performed by exposure to the ultrasound acoustic field with the generation of acoustic cavitation in the focal point of the focused ultrasound field and the water tank of an ultrasound cleaner. These Hydrophones were not damaged by the measurement of the acoustic field formed by a high-intensity focused ultrasound device.
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Influence of tough Hydrophone shapes with titanium front plate and hydrothermal PZT thick film on distribution of acoustic bubbles around focal point of HIFU transducer
2015 IEEE International Ultrasonics Symposium (IUS), 2015Co-Authors: Nagaya Okada, Michihisa Shiiba, Minoru K. Kurosawa, Shinichi TakeuchiAbstract:Novel tough Hydrophones were developed by the depositing hydrothermally synthesized lead zirconate titanate thick film on the back-side surface of Ti plate to protect from acoustic cavitation. This Hydrophone was resistant to damage at a high-intensity acoustic field formed by a high-intensity focused ultrasound (HIFU) transducer. Since the generation of acoustic bubbles cannot be avoided at high-intensity ultrasound field, an influence of the tough Hydrophone's shape on the spatial distribution of acoustic bubbles around focal point of HIFU transducer was investigated for accurate and precise evaluation of acoustic fields. As the result of the visualization by sonochemiluminescence in luminol, a stripe pattern derived from the standing wave was observed. Similarly, the trapping acoustic bubbles derived from the standing wave and moving acoustic bubbles derived from acoustic radiation forces were observed using visualization by the ultrasonic diagnostic equipment. By contrast, as the result of the observation using needle type Hydrophone, the amount of the trapping acoustic bubbles reduced, while the moving bubbles remained and thinned in shape. The present shape of tough Hydrophone tip was good use for low frequency ranges several tens kHz, whereas the influence of existence of the tough Hydrophone with round shape tip was reduced as compared to that with flat shaped tip at high frequency.
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frequency characteristics of receiving sensitivity and waveform of an anti acoustic cavitation Hydrophone
Japanese Journal of Applied Physics, 2014Co-Authors: Michihisa Shiiba, Nagaya Okada, Takeyoshi Uchida, Tsuneo Kikuchi, Minoru Kurosawa, Shinichi TakeuchiAbstract:Novel anti-cavitation Hydrophones were fabricated by depositing a hydrothermally synthesized lead zirconate titanate polycrystalline film on the back of a titanium plate. These Hydrophones were not damaged by the measurement of the acoustic field formed by a high-intensity focused ultrasound (HIFU) device. The Hydrophones were designed using Mason's equivalent circuit and by numerical simulation to improve their receiving characteristics for the measurement of the HIFU device. High receiving sensitivity with flat frequency characteristics was obtained by using a backing material with a specific acoustic impedance of about 20 × 106 kg/(m2 s) [Rayl]. We developed a new type of Hydrophone using a tin and titanium rods as backing materials, which have specific acoustic impedances of 24 × 106 and 27 × 106 kg/(m2 s), respectively. The fabricated anti-cavitation Hydrophone showed wide frequency characteristics of the receiving sensitivity. Furthermore, we observed the output waveform with distortion due to nonlinear propagation using the fabricated anti-cavitation Hydrophone. This Hydrophone was not damaged by exposure to a high-intensity acoustic field of an ultrasound cleaner under acoustic cavitation for duration of about ten times longer than the conventional commercial Hydrophone.
Wolfgang Eisenmenger - One of the best experts on this subject based on the ideXlab platform.
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The fiber optic probe Hydrophone
Proceedings of IEEE Ultrasonics Symposium ULTSYM-94, 1994Co-Authors: C. Wurster, J. Staudenraus, Wolfgang EisenmengerAbstract:We present a new type of Hydrophone based on a fiber-optic sensor principle for shock wave and ultrasonic measurements in water. Its detection mechanism is based on the change of the optical reflection coefficient at the end surface of a glass fiber in water by pressure signals. The relation between the intensity of the reflected light and the water pressure is defined by material constants so that calibration by reference is not necessary. Shock wave measurements were made with the fiber optic probe Hydrophone and compared with the results obtained by PVDF membrane and needle Hydrophones. Important advantages are high resolution in space and time, a reproducible response also to negative pressure signals with high accuracy, high cavitation threshold, large bandwidth (>1 GHz), ideal electromagnetic shielding, high deterioration resistance and simple calibration control
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fibre optic probe Hydrophone for ultrasonic and shock wave measurements in water
Ultrasonics, 1993Co-Authors: J. Staudenraus, Wolfgang EisenmengerAbstract:Aimed at lithotripter acoustic output measurements, a new fibre-optic probe Hydrophone overcomes most of the problems involved with the use of piezoelectric Hydrophone technology in non-linear ultrasonic and shock-wave fields. The fibre-optic principle allows for extremely wide bandwidth (larger than 1 GHz) and superior electromagnetic shielding. Contrary to hitherto existing Hydrophones a high cavitation threshold at the water-silica interface provides undistorted detection of strong rarefractional pulse pressures. Considering pure compression there is good agreement between maximum pulse pressure derived from fibre-optic Hydrophone theory and the corresponding amplitudes obtained from acoustically calibrated PVDF membrane and needle Hydrophones.
Wendong Zhang - One of the best experts on this subject based on the ideXlab platform.
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A Monolithic Integration Bio-Inspired Three-Dimensional MEMS Vector Hydrophone
IEEE Access, 2019Co-Authors: Jinlong Song, Guojun Zhang, Renxin Wang, Zhenzhen Shang, Lansheng Zhang, Wendong ZhangAbstract:Three-dimensional vector Hydrophone plays an important role in underwater spatial location. In order to solve the problems of monolithic integration and linearity of previous three-dimensional vector Hydrophones, a three-dimensional micro-electro-mechanical system (MEMS) vector Hydrophone based on the piezoresistive effect and bio-inspired principle is proposed in this paper. Different from previous three-dimensional vector Hydrophone, this three-dimensional MEMS vector Hydrophone is monolithically integrated. It has the characteristics of high consistency and batch production. Acoustic pressure gradients in xand y-directions are detected by the cilium, and acoustic pressure gradient in the z direction is detected by the supporting block and beams. Mathematical models of longitudinal stress on the surface of beams and the first three-order natural frequencies of the Hydrophone are established. The simulation results prove the accuracy of the mathematical models. Specific structure parameters of Hydrophone are determined and then the designed Hydrophone is fabricated on a silicon-on-insulator (SOI) wafer. Finally, the sensitivities and directivities of designed Hydrophone are tested. The sensitivities of X-channel and Z-channel are -187 dB and -163 dB (0 dB referring to 1 VμPa-1) at 400 Hz, respectively. The test results show that the Hydrophone promising in spatial location.
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The Development of the Differential MEMS Vector Hydrophone.
Sensors, 2017Co-Authors: Guojun Zhang, Nixin Shen, Xubo Wang, Wendong ZhangAbstract:To solve the problem that MEMS vector Hydrophones are greatly interfered with by the vibration of the platform and flow noise in applications, this paper describes a differential MEMS vector Hydrophone that could simultaneously receive acoustic signals and reject acceleration signals. Theoretical and simulation analyses have been carried out. Lastly, a prototype of the differential MEMS vector Hydrophone has been created and tested using a standing wave tube and a vibration platform. The results of the test show that this Hydrophone has a high sensitivity, Mv = −185 dB (@ 500 Hz, 0 dB reference 1 V/μPa), which is almost the same as the previous MEMS vector Hydrophones, and has a low acceleration sensitivity, Mv = −58 dB (0 dB reference 1 V/g), which has decreased by 17 dB compared with the previous MEMS vector Hydrophone. The differential MEMS vector Hydrophone basically meets the requirements of acoustic vector detection when it is rigidly fixed to a working platform, which lays the foundation for engineering applications of MEMS vector Hydrophones.
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research of doa estimation based on single mems vector Hydrophone
Sensors, 2009Co-Authors: Wendong Zhang, Guojun Zhang, Ling Gang Guan, Kai Rui Zhang, Jianping WangAbstract:The MEMS vector Hydrophone is a novel acoustic sensor with a "four-beam- cilia" structure. Based on the MEMS vector Hydrophone with this structure, the paper studies the method of estimated direction of arrival (DOA). According to various research papers, many algorithms can be applied to vector Hydrophones. The beam-forming approach and bar graph approach are described in detail. Laboratory tests by means of the a standing-wave tube are performed to validate the theoretical results. Both the theoretical analysis and the results of tests prove that the proposed MEMS vector Hydrophone possesses the desired directional function.
Gerald R. Harris - One of the best experts on this subject based on the ideXlab platform.
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Pressure Pulse Distortion by Needle and Fiber-Optic Hydrophones due to Nonuniform Sensitivity
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2018Co-Authors: Keith A. Wear, Gerald R. HarrisAbstract:Needle and fiber-optic Hydrophones have frequency-dependent sensitivity, which can result in substantial distortion of nonlinear or broadband pressure pulses. A rigid cylinder model for needle and fiber-optic Hydrophones was used to predict this distortion. The model was compared with measurements of complex sensitivity for a fiber-optic Hydrophone and three needle Hydrophones with sensitive element sizes (d) of 100, 200, 400, and 600 μm. Theoretical and experimental sensitivities agreed to within 12 ± 3% [root-mean-square (RMS) normalized magnitude ratio] and 8° ± 3° (RMS phase difference) for the four Hydrophones over the range from 1 to 10 MHz. The model predicts that distortions in peak positive pressure can exceed 20% when d/λ0 7% and can exceed 40% when d/λ0 14%, where λ0 is the wavelength of the fundamental component and SI is the fraction of power spectral density contained in harmonics. The model predicts that distortions in peak negative pressure can exceed 15% when d/λ0
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Correction for frequency-dependent Hydrophone response to nonlinear pressure waves using complex deconvolution and rarefactional filtering: application with fiber optic Hydrophones
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2015Co-Authors: Keith A. Wear, Paul Gammell, Subha Maruvada, Gerald R. HarrisAbstract:Nonlinear acoustic signals contain significant energy at many harmonic frequencies. For many applications, the sensitivity (frequency response) of a Hydrophone will not be uniform over such a broad spectrum. In a continuation of a previous investigation involving deconvolution methodology, deconvolution (implemented in the frequency domain as an inverse filter computed from frequency-dependent Hydrophone sensitivity) was investigated for improvement of accuracy and precision of nonlinear acoustic output measurements. Timedelay spectrometry was used to measure complex sensitivities for 6 fiber-optic Hydrophones. The Hydrophones were then used to measure a pressure wave with rich harmonic content. Spectral asymmetry between compressional and rarefactional segments was exploited to design filters used in conjunction with deconvolution. Complex deconvolution reduced mean bias (for 6 fiber-optic Hydrophones) from 163% to 24% for peak compressional pressure (p+), from 113% to 15% for peak rarefactional pressure (p-), and from 126% to 29% for pulse intensity integral (PII). Complex deconvolution reduced mean coefficient of variation (COV) (for 6 fiber optic Hydrophones) from 18% to 11% (p+), 53% to 11% (p-), and 20% to 16% (PII). Deconvolution based on sensitivity magnitude or the minimum phase model also resulted in significant reductions in mean bias and COV of acoustic output parameters but was less effective than direct complex deconvolution for p+ and p-. Therefore, deconvolution with appropriate filtering facilitates reliable nonlinear acoustic output measurements using Hydrophones with frequency-dependent sensitivity.
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Suppression of pressure measurement artifacts from fiber optic Hydrophones using complex deconvolution of sensitivity
IEEE International Ultrasonics Symposium IUS, 2014Co-Authors: Keith A. Wear, Gerald R. Harris, Yunbo Liu, Subha Maruvada, Paul GammellAbstract:Nonlinear acoustic signals contain significant energy at many harmonic frequencies. For many applications, the sensitivity (frequency response) of a Hydrophone will not be uniform over such a broad spectrum. In a continuation of a previous investigation involving deconvolution methodology, deconvolution (implemented in the frequency domain as an inverse filter computed from frequency-dependent Hydrophone sensitivity) was investigated for improvement of accuracy and precision of nonlinear acoustic output measurements. Time delay spectrometry (TDS) was used to measure complex sensitivities for six fiber-optic Hydrophones. The Hydrophones were then used to measure a pressure wave with rich harmonic content. Spectral asymmetry between compressional and rarefactional segments was exploited in order to design filters used in conjunction with deconvolution. Complex deconvolution reduced mean bias (for 6 fiber-optic Hydrophones) and mean coefficient of variation (COV) for peak compressional pressure (p+), peak rarefactional pressure (p-), and pulse intensity integral (PII). Deconvolution based on sensitivity magnitude or the minimum phase model also resulted in significant reductions in mean bias and COV of acoustic output parameters but was less effective than direct complex deconvolution for p+ and p-. Therefore, deconvolution with appropriate filtering facilitates reliable nonlinear acoustic output measurements using Hydrophones with frequency-dependent sensitivity.
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Improved measurement of acoustic output using complex deconvolution of Hydrophone sensitivity
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2014Co-Authors: Keith A. Wear, Paul Gammell, Subha Maruvada, Gerald R. HarrisAbstract:The traditional method for calculating acoustic pressure amplitude is to divide a Hydrophone output voltage measurement by the Hydrophone sensitivity at the acoustic working frequency, but this approach neglects frequency dependence of Hydrophone sensitivity. Another method is to perform a complex deconvolution between the Hydrophone output waveform and the Hydrophone impulse response (the inverse Fourier transform of the sensitivity). In this paper, the effects of deconvolution on measurements of peak compressional pressure (p+), peak rarefactional pressure (p-), and pulse intensity integral (PII) are studied. Time-delay spectrometry (TDS) was used to measure complex sensitivities from 1 to 40 MHz for 8 Hydrophones used in medical ultrasound exposimetry. These included polyvinylidene fluoride (PVDF) spot-poled membrane, needle, capsule, and fiber-optic designs. Subsequently, the 8 Hydrophones were used to measure a 4-cycle, 3 MHz pressure waveform mimicking a pulsed Doppler waveform. Acoustic parameters were measured for the 8 Hydrophones using the traditional approach and deconvolution. Average measurements (across all 8 Hydrophones) of acoustic parameters from deconvolved waveforms were 4.8 MPa (p+), 2.4 MPa (p-), and 0.21 mJ/cm2 (PII). Compared with the traditional method, deconvolution reduced the coefficient of variation (ratio of standard deviation to mean across all 8 Hydrophones) from 29% to 8% (p+), 39% to 13% (p-), and 58% to 10% (PII).
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Time-delay spectrometry measurement of magnitude and phase of Hydrophone response
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2011Co-Authors: Keith A. Wear, Paul Gammell, Subha Maruvada, Gerald R. HarrisAbstract:A method based on time-delay spectrometry (TDS) was developed for measuring both magnitude and phase response of a Hydrophone. The method was tested on several types of Hydrophones used in medical ultrasound exposimetry over the range from 5 to 18 MHz. These included polyvinylidene fluoride (PVDF) spot-poled membrane, needle, and capsule designs. One needle Hydrophone was designed for high-intensity focused ultrasound (HIFU) applications. The average reproducibility (after repositioning the Hydrophone) of the phase measurement was 2.4°. The minimum-phase model, which implies that the phase response is equal to the inverse Hilbert transform of the natural logarithm of the magnitude response, was tested with TDS Hydrophone data. Direct TDS-based measurements of Hydrophone phase responses agreed well with calculations based on the minimum-phase model, with rms differences of 1.76° (PVDF spot-poled membrane Hydrophone), 3.10° (PVDF capsule Hydrophone), 3.43° (PVDF needle Hydrophone), and 3.36° (ceramic needle Hydrophone) over the range from 5 to 18 MHz. Therefore, phase responses for several types of Hydrophones may be inferred from measurements of their magnitude responses. Calculation of phase response based on magnitude response using the minimum-phase model is a relatively simple and practical alternative to direct measurement of phase.
Volker Wilkens - One of the best experts on this subject based on the ideXlab platform.
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Secondary Complex-valued Hydrophone Calibration up to 100 MHz Using Broadband Pulse Excitation and a Reference Membrane Hydrophone
2019 IEEE International Ultrasonics Symposium (IUS), 2019Co-Authors: Volker Wilkens, Sven Sonntag, Martin WeberAbstract:Comparability and reliability of acoustic output declarations of medical devices can be improved by compensating the impact of Hydrophone frequency responses on output parameters. However, extended calibration data are needed for the application of waveform deconvolution. This study addresses a method for secondary Hydrophone calibration that can be applied outside of metrology institutes by Hydrophone users to determine the appropriate frequency responses of working Hydrophones in their laboratories. The proposed substitution method provides complex-valued calibration data from 0.5 MHz to 100 MHz.
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HIFU waveform measurement at clinical amplitude levels: Primary Hydrophone calibration, waveform deconvolution and uncertainty estimation
2017 IEEE International Ultrasonics Symposium (IUS), 2017Co-Authors: Martin Weber, Volker WilkensAbstract:High-intensity focused ultrasound (HIFU) fields can be characterized by specific Hydrophones that are able to withstand the large acoustical pressures used in medical applications. Such Hydrophones may show a non-flat frequency response due to their being strengthened by protection layers against cavitation damage. Therefore, Hydrophone calibration data should be used in deconvolution in order to reconstruct the ultrasonic pressure waveforms. A regularization filter should be applied during deconvolution to suppress high-frequency noise. This paper describes the metrological chain from primary Hydrophone calibration to Hydrophone measurement and waveform deconvolution, including uncertainty estimation for deconvolved Hydrophone signal data (for example, HIFU field measurements).
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amplitude and phase calibration of Hydrophones up to 70 mhz using broadband pulse excitation and an optical reference Hydrophone
Journal of the Acoustical Society of America, 2004Co-Authors: Volker Wilkens, C. KochAbstract:A substitution calibration technique for piezoelectric ultrasonic Hydrophones is presented that uses an optical multilayer Hydrophone as the reference receiver. Broadband nonlinearly distorted focused pulses are first measured with the reference Hydrophone and then with the Hydrophone to be calibrated. By Fourier transformation of the time wave forms and division of the frequency spectra, the complex-valued frequency response of the Hydrophone under test is obtained in a broad frequency range in a very fast and efficient way and with high frequency resolution. The results obtained for a membrane Hydrophone and a needle-type Hydrophone are compared with those obtained by independent calibration techniques such as primary calibration using optical interferometry and secondary calibration using time-delay spectrometry, and good agreement is found. The calibration data obtained are apt to improve the results of ultrasound exposure measurements using broadband voltage-to-pressure conversion. This is demonstrat...
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Phase calibration of Hydrophones: heterodyne time-delay spectrometry and broadband pulse technique using an optical reference Hydrophone
Journal of Physics: Conference Series, 2004Co-Authors: Ch Koch, Volker WilkensAbstract:Two Hydrophone calibration techniques are presented which provide amplitude and phase of Hydrophone sensitivity. Heterodyne time-delay spectrometry can be applied in the frequency range from 0.5 to 50 MHz to all common Hydrophones but needs a standard to obtain absolute values. A pulse technique between 1 and 70 MHz allows exploiting of an optical multilayer Hydrophone as a phase standard. In combination with HTDS, a calibration service is established that covers the complete spectrum of common piezoelectric and optical Hydrophones for absolute amplitude and phase calibration. The measured complex frequency responses form the basis of deconvolution procedures suitable for the correction of measurements of, for example, the output of ultrasound diagnostic machines.
