High-resolution acoustic imaging using multi-carrier waveforms synthesized by genetic algorithm

We propose an acoustic imaging method that can achieve high resolution and high image quality. Our imaging method is based on a combination of pulse compression and the synthetic transmit aperture (STA). Conventionally, these methods have often used signals modulated with M-sequences because of their relatively good orthogonality. However, the image quality is degraded by noise in the correlations between such signals. Our proposed method addresses this issue by intentionally synthesizing signals with suppressed correlations. We devised a new method for signal synthesis, in which the sub-carrier parameters of multi-carrier signals were optimized by a genetic algorithm. The simulation results showed that the optimized signals reduced the correlation noise by 7.8 dB compared to the conventional M-sequence signals. The improvement in image quality was also verified by the simulation.