A Fourier transform-based sidelobe reduction method in ultrasound imaging

Focusing is widely used to increase the resolution in medical ultrasound im aging systems. Focusing increases signal levels returning from the mainlobe direction and decreases those from sidelobe directions. The sidelobes, whe n not completely canceled, deteriorate the resulting image resolution. This paper proposes a method of improving the resolution by scaling the receive d signal according to the ratio between the mainlobe and the sidelobe level s computed in the frequency domain by the use of Fourier transform. The pro posed method is verified by computer simulation and experiment and is shown to be highly effective in narrowing the mainlobe width and decreasing the sidelobe levels at the same time.