Sound field measuring apparatus and measuring method

Abstract

The invention discloses a sound field measuring apparatus. Light emitted by a laser is successively reflected by a sound field generated by a transmitting lens, a collimator lens, a half mirror and anacoustic transducer as well as a reflection mirror and is then returned by virtue of the original sound field, after the light beam is deflected for 90 degrees by virtue of a light splitter, the light passes through a Fourier transform lens to perform the space filter treatment on a rear focal plane of the Fourier transform lens, so that the sound-field imaging can be realized; an image sensor ismoved to the rear focal plane of a variable lens to receive a diffraction spot, a sound speed can be calculated according to the distance of the diffraction spot, and the sound pressure is calculatedaccording to the distribution of the spot intensity; and a diaphragm is arranged between the sound field and the light splitter and can be used for measuring the sound pressure of a local sound fieldarea. By adopting the sound field measuring apparatus, the imaging of the sound fields in various forms in transparent fluid can be realized, and the plane sound field, the approximate plane sound field and the intensity of the approximate plane sound field area in the sound field can be quantitatively measured; by virtue of the calibration of the transducer, the measurement of a pulse wave and continuous traveling wave plane sound field or approximate plane sound field can be realized; and by adopting the reflection mirror, the light passes through the sound field twice, so that the imagingand measuring sensitivity can be improved.

Description

technical field [0001] The invention relates to a sound field measuring device and a measuring method, belonging to the field of ultrasonic technology. Background technique [0002] The imaging and measurement of sound field are widely used in ultrasonic detection and ultrasonic medical treatment, especially in ultrasonic diagnosis. The sound pressure needs to be strictly limited and cannot exceed the specified value. Distribution measurement and quantitative measurement of sound field intensity, so it is particularly important to measure the distribution of sound field intensity and accurately quantitatively measure sound pressure. [0003] Traditional measurement methods have certain limitations, common measurement methods are: [0004] (1) Hydrophone method: It is suitable for the measurement of sound fields in various fluids. However, this method is an intrusive measurement method, and the hydrophone must be calibrated in advance; the introduction of the hydrophone cha...

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Problems solved by technology

However, this method is only suitable for the measurement of low-frequency ultrasonic fields below 50KHz, and the quantitative measurement of high-frequency sound fields above 0.3MHz is difficult

[0009] (6) Schlieren method: the light beam passes through the sound field once, and the quantitative measurement of the sound field can be carried out, but the sensitivity is relatively low. For the sound field with a short distance of acousto-optic action or a small sound pressure, the measurement sensitivity is not high, and it is often impossible to measure

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