Imaging beyond the Born approximation: an experimental investigation with an ultrasonic ring array

Area of Science:

• Acoustics
• Wave physics
• Imaging science

Background:

• The classical diffraction limit restricts imaging resolution to half the wavelength of the probing wave.
• The Born approximation, often used in scattering experiments, neglects wave distortion due to multiple scattering.
• Multiple scattering can encode sub-wavelength information, enabling super-resolution.

Purpose of the Study:

• To demonstrate super-resolution imaging beyond the classical diffraction limit using ultrasonic waves.
• To investigate the effect of multiple scattering on resolution.
• To achieve super-resolution for extended objects, overcoming limitations of previous studies.

Main Methods:

• Utilized ultrasonic pressure waves for object probing.
• Employed a ring transducer array for full-view excitation and detection.
• Implemented techniques to overcome high noise levels (signal-to-noise ratio below 0 dB).

Main Results:

• Achieved a resolution better than lambda/4, approaching lambda/6.
• Demonstrated super-resolution for both small and extended objects.
• Successfully imaged objects despite significant noise in the measurements.

Conclusions:

• The classical diffraction limit can be overcome by accounting for multiple scattering effects.
• Super-resolution imaging is feasible using ultrasonic waves, even in noisy conditions.
• This technique offers potential for enhanced imaging of extended objects at sub-wavelength scales.