Ultrasound time of flight tomography for flame temperature measurement based on phase comparison

H.I. Schlaberg, Shi Liu, Zhihong Li

School of Control and Computer Engineering, North China Electric Power University, Beijing,102206, China, email: h.i.schlaberg@ieee.org

ABSTRACT

Ultrasound time of flight tomography measures the time between the emission and the arrival of an ultrasonic wave and reconstructs an image of the properties in the interior cross section of the region of interest. In applications where the positions of objects with a large difference in acoustic impedance from the background medium are sought, the accuracy of the measurement of the Time Of Flight (TOF) is usually of the order of one wavelength. Examples are gases in liquid or solids in liquid. In applications where the reconstruction of temperature variations is of interest, the measurements have to be more precise to provide a sufficient resolution. This paper describes the use of phase comparison between the emitted and received signal to determine the arrival time with an accuracy of the order of a degree of the wavelength and examines alternative methods to measure the TOF with high resolution. This work is carried out for the application of visualising the temperature of a gas flame.

Keywords Ultrasound tomography, phase comparison, flame temperature