Synthetic aperture focusing techniques applied in the near field of a focused transducer

Synthetic aperture focusing techniques (SAFT) are used to improve the signal-to-noise ratio (SNR) of ultrasonic images. The effect of applying SAFT in the near-field of a focused transducer is studied. The variations in the near-field zone are derived analytically and used to modify the SAFT algorithm. SAFT is performed on both the RF data and the envelope of the signal. Experimental results demonstrating the effectiveness of the approach are presented.