What Is Acoustic Holography?

The acoustic imaging technology using the wavefront reconstruction method is an acoustic imaging technology that introduces the principle of optical holography into the field of acoustics and uses the principle of interference to obtain all information (amplitude distribution and phase distribution) of the sound field of the observed object.

The acoustic imaging technology using the wavefront reconstruction method is an acoustic imaging technology that introduces the principle of optical holography into the field of acoustics and uses the principle of interference to obtain all information (amplitude distribution and phase distribution) of the sound field of the observed object.

Chinese name

Acoustic holography

Foreign name

acousticalholography

Figure 1 Acoustic hologram of cooling fan

Figure 2 Related Books

Figure 3 Near-field acoustic holographic test system

Principle of acoustic holography

The principle of acoustic holography is the same, that is, the amplitude and phase of the object wave are recorded by the interference principle of waves, and the image of the object is reproduced by the principle of diffraction. The difference is that ultrasonic waves are used instead of light waves. ^[1]

Acoustic holography

Acoustic holographic detection process includes two steps, namely obtaining an acoustic hologram and reconstructing the hologram to obtain a visible image of the object. If these two steps are performed simultaneously, real-time imaging can be achieved. ^[2]

Classification of acoustic holography

Acoustic holography technology can be generally divided into: conventional acoustic holography, near-field acoustic holography, and far-field acoustic holography. Among them, near-field acoustic holography (NAH) has the widest application area, the highest resolution, and the strongest operability.

In addition, according to the type of the acoustic detector used, the recording medium, the specific working method and the application situation, acoustic holography can also be divided into liquid surface ultrasonic holography, laser-ultrasonic holography, liquid crystal display ultrasonic holography, and so on.

Acoustic Holography

Acoustic holography can detect the source and propagation of sound, can be used for non-destructive inspection, and can show the shape and size of internal defects in the test piece.

Research Status of Acoustic Holography

At present, domestic scholars studying near-field acoustic holography mainly include He Yi of Harbin Engineering University, Chen Xinzhao of Hefei University of Technology, Chen Kean of Northwestern Polytechnical University, Shanghai Jiaotong University, Professor Lu Yancai of Zhejiang University of Technology, and other academics.