Acoustic travel-time measurement in acoustic temperature field monitoring

The key for acoustic temperature field measurement is to measure acoustic travel-time accurately. An acoustic travel-time measurement system based on virtual instrument for acoustic temperature field monitoring is introduced. The estimation methods of travel-time using cross-correlation and interpolation are proposed and investigated. Simulation research in MATLAB shows that: restricted by the sampling interval, the accuracy of acoustic travel-time estimation by directly cross-correlating of the transmitted and received sampling signals is not high; a higher accuracy can be achieved by cubic spline interpolating the part cross-correlogram near the cross-correlation peak when the noise is weak; if the noise is moderate or strong, a higher accuracy can be achieved by linear interpolating the transmitted and received sampling signals before calculating their cross-correlation function.