In-vitro B-mode contrast imaging using chirp excitation with a non-linear decoder

To quantitatively evaluate the performance of a non-linear chirp compression technique, we made b-mode images of a flow phantom using pulse and chirp excitations in both fundamental and second harmonic mode. Flow channel sizes as measured from the obtained images show good agreement between the imaging methods, with only a small loss in axial resolution for chirp harmonic imaging. However, range side-lobes were present in the chirp harmonic images. SNR improvements of up to 11 dB were found for chirp excitation relative to pulse excitation.