Based On The Labview Acoustic CT Three-dimensional Temperature Field Reconstruction System

As a new non-contact temperature measurement technology, Acoustic temperaturemeasurement technology has many advantages, wide temperature range, wide area ofmeasurement. This technology has been applied in industrial furnace combustion conditionmonitoring. Also it has carry out the new research in recent years, such as grain temperaturemeasurement.In the grain noise interference the acoustic signal transmission. In order to improve theaccuracy of acoustic propagation time measurement in the grain, this paper proposes a newmethod for time delay estimation. This method will two remote microphone receives the voicesignals respectively with speaker do cross-correlation time delay estimation with referencesignal. Then two time delay value to do subtraction, system can obtain acoustic time of flightbetween the two microphone. Because of using known waveform as reference signal, so thistime delay estimation method can ignore the noise of emission signal, and avoid theconstraints in the traditional method. The condition is that the noise at the receiving andlaunching part is unrelated. Through the experimental in soybean results show that this timedelay estimation method has better ability to resist noise.In this paper, from two aspects of hardware and software platform design, detailedintroduces the acoustic CT three-dimensional temperature field test system. The system tskesLabVIEW as its software design platform. By calling MATLAB script processes of soundtravel time calculating and temperature field reconstruction. In order to improve the operationefficiency of the system, this paper adopts multithreading technology, make the signalacquisition and data processing in parallel operation.The ability of reconstruction of the system depends on the distribution of sensor locationand form sound effective path selection method. Therefore, This article has carried on thesimulation in homogeneous temperature field and adding a single hot spot uneven temperaturefield. Simulation setup area size is1m×1m×1m,16sensors for reconstruction. This articledesign the distribution of the two kinds of sensors, and two methods of acoustic effective pathselection. The simulation results of the system show that when places the sensor on the surfaceof the cube and middle point of edge and vertex edges, selects remove edge the sound wavesflight path selection method can get the best effect. And, the system could adjust the filter parameter, in order to improve the system’s ability of resist noise.In the laboratory, based on the reconstruction results of the uniform and non-uniformtemperature field show that temperature field acoustic CT testing system can be continuousand stable operation. And, the system efficiency of using multithreading technology to doublecompared with single thread.