PURPOSE: To accurately restore a sent pulse wave and to improve the resolution in the depth direction of a sample by restoring a sent waveform from the transfer function of the passage of ultrasonic pulses which are made incident on the sample.
CONSTITUTION: The converged ultrasonic wave is made incident on the sample 24 and the ultrasonic wave reflected by the sample 24 is converted into an electric signal. The electric signal is supplied to a gate circuit 30 to extract a reflected wave from an optional depth position of the sample 24. this reflected signal is converted 31 into a digital signal, which is processed through the Fourier transformation of an arithmetic circuit 32. Further, the transfer function of the ultrasonic pulses is calculated 32 from reflection position information of the reflected wave on the sample 24 which is extracted by a position detecting circuit 27 for the relative position between an acoustic lens 23 and the sample 24, the sample density and sound speed, the time difference between the reflected waves from the sample surface and the sample inside, the focal length of the lens 23 in the ultrasonic wave propagation medium positioned between the acoustic lens 23 and sample 24, the absorption coefficient of the ultrasonic propagation medium, and the pupil function of the lens 23 and observation image data is then generated according to the transfer function.
ISHIBASHI JUNICHI
ENDO TOMIO
