Signal processing method and signal processing device for ultrasonic inspection apparatus

A signal processing device for an ultrasonic inspection apparatus in which an ultrasonic pulse is transmitted to a target object at a predetermined period, and a flaw present in said target object is detected on the basis of a high-frequency echo signal output from an ultrasonic transmit-receive unit for receiving a reflected wave, comprising:

• A/D converting means for converting the echo signal into a digital signal at a predetermined sampling frequency;
• measurement time interval designating means for designating a measurement time interval in the predetermined period;
• storing means for sequentially storing, at a write frequency equal to the sampling frequency, sampling data, in the measurement time interval, of the echo signal converted into the digital signal to sequentially output the stored sampling data at a read frequency lower than the write frequency;
• a digital filter for performing a frequency discrimination process to the echo signal sequentially output from said storing means;
• and
• flaw determining means for determining the presence/absence of the flaw on the basis of the echo signal to which the frequency discrimination process is performed.

A signal processing device for an ultrasonic inspection apparatus in which an ultrasonic pulse is transmitted to a target object at a predetermined period, and a flaw present in said target object is detected on the basis of a high-frequency echo signal output from an ultrasonic transmit-receive unit for receiving a reflected wave, comprising:

• A/D converting means for converting the echo signal into a digital signal at a predetermined sampling frequency;
• measurement time interval designating means for designating a measurement time interval in the predetermined period;
• first storing means for sequentially storing, at a write frequency equal to the sampling frequency, sampling data, in the measurement time interval, of the echo signal converted into the digital signal to sequentially output the stored sampling data at a read frequency lower than the write frequency;
• a digital filter for performing a frequency discrimination process to the echo signal sequentially output from said first storing means;
• second storing means for sequentially storing data of an echo signal output from said digital filter to sequentially output the stored data at a read frequency equal to the sampling frequency;
• and
• D/A converting means for converting an echo signal sequentially output from said second storing means into an analog signal.

A signal processing device for an ultrasonic inspection apparatus in which an ultrasonic pulse is transmitted to a target object at a predetermined period, and a flaw present in said target object is detected on the basis of a high-frequency echo signal output from an ultrasonic transmit-receive unit for receiving a reflected wave, comprising:

• A/D converting means for converting the echo signal into a digital signal at a predetermined sampling frequency;
• measurement time interval designating means for designating first and second measurement time intervals, which are different from each other, in the predetermined period;
• first storing means for sequentially storing, at a write frequency equal to the sampling frequency, sampling data, in the first measurement time interval, of the echo signal converted into the digital signal to sequentially output the stored sampling data at a read frequency lower than the write frequency;
• a first digital filter for performing a frequency discrimination process to the echo signal sequentially output from said first storing means;
• second storing means for sequentially storing data of an echo signal output from said digital filter to sequentially output the stored data at a read frequency equal to the sampling frequency;
• third storing means for sequentially storing, at a write frequency equal to the sampling frequency, sampling data, in the second measurement time interval, of the echo signal converted into the digital signal to sequentially output the stored sampling data at a read frequency lower than the write frequency;
• a second digital filter for performing a frequency discrimination process to an echo signal sequentially output from said third storing means;
• fourth storing means for sequentially storing data of an echo signal output from said second digital filter to sequentially output the stored data at a read frequency equal to the sampling frequency;
• and
• D/A converting means for synthesizing the echo signals output from said second and fourth storing means with each other to convert the echo signals into one analog signal.

A signal processing device for an ultrasonic inspection apparatus in which an ultrasonic pulse is transmitted to a target object at a predetermined period, and a flaw present in said target object is detected on the basis of a high-frequency echo signal output from an ultrasonic transmit-receive unit for receiving a reflected wave, comprising:

• A/D converting means for converting the echo signal into a digital signal at a predetermined sampling frequency;
• measurement time interval designating means for designating a measurement time interval in the predetermined period;
• storing means for sequentially storing, at a write frequency equal to the sampling frequency, sampling data, in the measurement time interval, of the echo signal converted into the digital signal to sequentially output the stored sampling data at a read frequency lower than the write frequency;
• a synchronous adding/averaging circuit for averaging, over a plurality of periods, an echo signal output from said storing means each time the predetermined period has passed;
• and
• flaw determining means for determining the presence/absence of the flaw on the basis of an echo signal output from said synchronous adding/averaging circuit.

A signal processing device for an ultrasonic inspection apparatus in which an ultrasonic pulse is transmitted to a target object at a predetermined period, and a flaw present in said target object is detected on the basis of a high-frequency echo signal output from an ultrasonic transmit-receive unit for receiving a reflected wave, comprising:

• A/D converting means for converting the echo signal into a digital signal at a predetermined sampling frequency;
• measurement time interval designating means for designating a measurement time interval in the predetermined period;
• first storing means for sequentially storing, at a write frequency equal to the sampling frequency, sampling data, in the measurement time interval, of the echo signal converted into the digital signal to sequentially output the stored sampling data at a read frequency lower than the write frequency;
• a synchronous adding/averaging circuit for averaging, over a plurality of periods, an echo signal output from said first storing means each time the predetermined period has passed;
• second storing means for sequentially storing data of an echo signal output from said synchronous adding/averaging circuit to sequentially output the stored data at a read frequency equal to the sampling frequency;
• and
• D/A converting means for converting an echo signal sequentially output from said second storing means into an analog signal.