Microwave-Induced Thermoacoustic Compressive Imaging With Metamaterial Coding

The microwave-induced thermoacoustic (TA) sensing has been proven to promise a great potential in clinical and biomedical applications. This novel technology has also been explored to boost its use in subsurface geophysical applications. A conventional TA sensing system, however, is greatly limited by either a slow scan or a dramatical cost, and making infeasible the real-time monitoring when covering large domains. One remarkable solution of such issues is to design a compressive sensing (CS)-based TA system, with the aim of reducing the sampling intensity necessary to high resolution imaging. Specifically, to favor the demand for CS, this work studies the appropriateness of metamaterial (MM) resonators and proposes a MM linear array-coded TA system to randomize the transmitted acoustics waves. To prove the efficacy, images obtained from both of the proposed TA system and the conventional TA system without coding are assessed and compared. Under the same scenario, the MM-coded TA system shows higher imaging capabilities and a better performance when using a much-limited amount of measurements or in noisy enviornments. This method opens the door for a fast scan of the geological imaging and the real-time monitoring of the underground flow.