Detecting method and detecting device

摘要

A detecting device includes a transmission signals generating means (9) for generating first and second transmission signals of different frequencies; ultrasonic wave transmission means (6) excited by the first and the second transmission signal, for transmitting ultrasonic pulses corresponding to the first and the second transmission signal to an object (8); and signal processing means (11) for carrying out a signal processing process on the first and the second echo, the signal processing process being such that detects phases of the first and the second echo corresponding to the first and the second transmission signal, which are received by the ultrasonic wave receiving means (10), an indeterminacy integer times as large as 2 pi of the phase of each of the first and the second echo is determined on the basis of the information of the amplitudes of the first or the second echo, and a distance from the ultrasonic wave transmission means through an object to the ultrasonic wave receiving means along an ultrasonic wave propagating path is detected on the basis of the determined phase of the first or the second echo.