RESEARCH ON MAGNETO–ACOUSTIC IMAGING UNDER CHIRP CURRENT EXCITATION

Magneto–acoustic signals reflect the electrical properties of tissues, which is meaningful for the diagnosis of tumors, bleeding and other diseases. The low signal-to-noise ratio (SNR) of the magneto–acoustic signals limits the image quality of the magneto–acoustic imaging. A chirp coded excitation signal processing method for magneto–acoustic imaging is proposed in this paper. The SNR of magneto–acoustic signal is improved. In this paper, magneto–acoustic signals under different pulse widths chirp coded excitation are studied by simulation and experimental measurement. The SNRs of the magneto–acoustic signals are increased by 7.5, 16.3, 42.2, and 90.1 times under 10, 20, 50 and 100[Formula: see text][Formula: see text]s chirp excitation, respectively, for the beef and copper ring sample. At the same time, the processing time was significantly shortened to 1.2% of the average method under the single pulse excitation. The chirp coded method is of great significance to improve the SNR of magneto–acoustic signals, image quality and imaging efficiency.