Pseudo Chirp-Barker-Golay coded excitation in ultrasound imaging

Coded excitation can improve the signal-to-noise ratio (SNR) without degrading the axial resolution in medical ultrasound imaging. SNR gain is basically obtained by increasing the pulse duration, however, the length of binary-phase modulation signal is limited to certain values. In this paper, a new pseudo Chirp-Barker-Golay (PCBG) coded excitation method is proposed. The new kind of phase modulation code is created by modulating Golay code with Barker code, allowing to choose the code length more flexibly. And pseudo Chirp signal replaces the base pulse as a carrier, which lead to additional SNR gain by setting the time bandwidth product (TBP) of the carrier. For the compression method, mismatched filter with Chebyshev window is used to eliminate sidelobes. Field II simulation results of point targets phantom and cyst phantom of B-mode image show that the PCBG method can improve SNR, axial resolution and lateral resolution, and has better contrast performance better resistance to noise, and lower sidelobes. The CNR is improved to 3.9314 with CR kept to 54.0234dB.