Real-time temperature field measurement based on acoustic tomography

Acoustic tomography can be used to measure temperature field from the time-of-flight (TOF). In order to capture real-time temperature field change and accurately yield quantitative temperature image, two improvements on the conventional acoustic tomography system are studied: simultaneous acoustic transmission and TOF collection along multiple ray paths, and offline iteration reconstruction algorithm. In system operation, all the acoustic transceivers send the modulated and filtered wideband Kasami sequence simultaneously to facilitate fast and accurate TOF measurements using cross-correlation detection. For image reconstruction, iteration process is separated and executed offline beforehand to shorten computational time for online temperature field reconstruction. The feasibility and effectiveness of the developed methods are validated in simulation study. Simulation results demonstrate that the proposed method can reduce the processing time per frame from 160 ms to 20 ms, while the reconstruction error remains less than 5%. Hence the proposed method has great potential to measure rapid temperature change with good temporal and spatial resolution.