Beamforming using the synthetic sine wave for ultrasonic imaging system

Synthetic sine wave employs pulsed plane wave as, transmit beam using a full aperture array with linear time delay curve. The received echoes in different. transmit directions at different transmit times are superposed at imaging points with proper time delay compensation using synthetic focusing schemes. This scheme, which uses full aperture on transmit, overcomes the low SNR problem in conventional synthetic focusing, and also features high lateral resolution by using two way dynamic focusing at all imaging depths. We have applied the scheme to obtain phantom and in-vivo images using a linear array of 5 MHz and 128 elements. In phantom test, experimental images show high resolution over a more extended imaging depth than conventional fixed point transmit and receive dynamic focusing schemes. In-vivo images show that the resolution could not overcome conventional focusing systems because of motion blurring and/or aberration of tissue, but that the frame rate can be increased by a factor of more than 5 compared to conventional focusing schemes, with competitive resolution at all imaging depths