Research On Three-Dimensional Temperature Field Reconstruction System Based On Acoustic Tomography

Temperature field measurement based on acoustic travel-time tomography is a typical application in computerized tomography. The advantages of acoustic temperature measurement technology are non-contact sensing, wide measuring area and quick in response.This paper introduces the designed of three-dimensional temperature field reconstruction system based on acoustic tomography with 20-channel. The hardware circuit of system is contained with sound wave transmitting/receiving device, sound wave transmitting circuit, sound wave receiving circuit, data acquisition module and the computer with sound card. The software of system is contained with hardware circuit controlled program, data acquired program, effective propagation paths selection program, time-delay estimation program and temperature field reconstruction program. This system can lay uniformly the 20 groups of sound wave transmitting/receiving device in the area, form 154 pieces of effective propagation paths, measure the acoustic travel-time of effective paths, and reconstruct temperature field on the basis of the obtained acoustic travel-time and three-dimensional temperature field of the reconstruction algorithm temperature field. The paper discusses the reconstruction system from hardware aspect and software aspect.In order to measure the acoustic travel-time in low SNR environments, the paper does the research of time-delay estimate method. The simulation in MATLAB environment showed that the multilayer correlation method, correlation method and second correlation method all can accurately estimate acoustic travel-time, and the measurement accuracy of multilayer correlation method has certain advantage.This paper also uses the three-dimensional temperature field of reconstruction system based on acoustic tomography and does the reconstructed experiment in the uniform temperature stereo space of laboratory. 20 groups of sound wave transmitting/receiving device decorate around the 1m×1m×1m measured area. Operating the system, it can get the acoustic travel-time in the effective path, do the pretreatment and calibration of sound wave data, then use the three-dimensional temperature field of reconstruction software based on acoustic method, and reconstruct the temperature distribution in the area being measured. Reconstruction results show that each other with correlation method, second correlation method and multilayer correlation method estimate the acoustic travel-time, and three methods also can accurately reconstruct the temperature distribution of measured area. And the results demonstrate the correctness of designed system.