Acoustic Velocity Measurement for Enhancing Laser UltraSound Imaging Based on Time Domain Synthetic Aperture Focusing...

Area of Science:

• Biomedical Engineering
• Acoustic Imaging
• Optical Physics

Background:

• Laser ultrasound (LUS) imaging offers non-contact ultrasound generation and detection.
• Accurate acoustic velocity is crucial for high-resolution image reconstruction in LUS.
• Current LUS methods often lack precise in situ acoustic velocity determination.

Purpose of the Study:

• To enhance laser ultrasound (LUS) image reconstruction using the time-domain synthetic aperture focusing technique (T-SAFT).
• To develop a method for in situ acoustic velocity extraction within the LUS imaging process.
• To demonstrate the efficacy of the enhanced LUS method in reconstructing embedded objects.

Main Methods:

• Developed an all-optic LUS system utilizing lasers for both ultrasound excitation and detection.
• Implemented an in situ acoustic velocity extraction technique by fitting a hyperbolic curve to B-scan images.
• Applied the extracted acoustic velocity within the T-SAFT algorithm for image reconstruction.

Main Results:

• Successfully reconstructed needle-like objects embedded in polydimethylsiloxane (PDMS) and chicken breast tissue.
• Demonstrated that accurate in situ acoustic velocity is vital for both depth localization and high-resolution LUS imaging.
• Numerical simulations and experimental results confirmed the operational principle and effectiveness of the method.

Conclusions:

• The developed method significantly enhances LUS image reconstruction accuracy and resolution.
• In situ acoustic velocity measurement is a critical factor for advanced T-SAFT in LUS.
• This work supports the future development of all-optic LUS for biomedical imaging applications.