Ultrasonic inspection method and ultrasonic inspection apparatus

An ultrasonic inspection apparatus comprising:

• an ultrasonic sensor;
• a control device that outputs a pulse signal to the ultrasonic sensor to generate and transmit ultrasonic waves, accepts a waveform signal in which the ultrasonic waves reflected or scattered by an object are received and converted by the ultrasonic sensor, and digitizes the waveform signal to acquire waveform data;
• and
• a computer that processes the waveform data acquired by the control device,
• wherein
• the computer executes
• modulation processing for modulating a plurality of waveform data by a phase modulation method or a linear frequency modulation method to generate composite waveform data, the plurality of waveform data being acquired in multiple inspections and under the same inspection conditions or acquired by duplication;
• and
• demodulation processing for demodulating the composite waveform data to generate compressed waveform data;
• wherein in the demodulation processing, multiple types of matched filters having different phases are generated by numerical analysis based on the pulse signal, a convolution integral is performed on the composite waveform data using the multiple types of matched filters to generate multiple types of compressed waveform data, and a phase of the matched filter corresponding to compressed waveform data having an amplitude that is a maximum among the multiple types of compressed waveform data is acquired as a phase of the waveform data.