Time-delay estimation of ultrasonic echoes based on the physical model matching

The estimation of time of flight (TOF) is fundamental to many ultrasonic-based techniques. This paper presents a novel method for estimating time delay of ultrasonic echoes based on vibration theory and signal processing methods. The method is inspired by the physical model of ultrasonic echoes that shows the rising edge of ultrasonic echoes depends on the damping factor of the vibration part of the ultrasonic transducer. The physical model is analyzed and simulated for the understand of the time-domain characters of ultrasonic echoes. For applications, the threshold method is also considered in the method. Two traditional methods of TOF are compared with the proposed by experiment data. It is shown that the proposed method can estimate the starting point of the ultrasonic echo quickly and effectively in the real ranging system.