Ultrasonic Measurement Method, Ultrasonic Measurement Apparatus, and Ultrasonic Sensor

• US 20100251821A1
• Filed: 04/05/2010
• Published: 10/07/2010
• Est. Priority Date: 04/06/2009
• Status: Active Grant

• Current Assignee: Hitachi-Ge Nuclear Energy Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi-Ge Nuclear Energy Limited (Hitachi, Ltd.)
• Inventors: Baba, Atsushi, Kono, Naoyuki, MIZOTA, Hirohisa
• Granted Patent: US 8,210,043 B2
• Time in Patent Office: Days
• US Class Current: 73/602
• CPC Class Codes: G01N 2291/0289 Internal structure, e.g. defects, grain size, texture
• CPC Class Codes: G01N 2291/106 one or more transducer arrays
• CPC Class Codes: G01N 29/262 by electronic orientation or focusing, e.g. with phased arrays phased arrays per se G10K11/34
• CPC Class Codes: G10K 11/345 using energy switching from one active element to another

Abstract

An ultrasonic measurement method and an ultrasonic measurement apparatus are capable of performing an inspection for a short time with a high SN ratio and a small variation (that depends on an inspection direction) in sensitivity in a process for detecting a defect in all directions at 360 degrees using a matrix array sensor without performing mechanical scanning in all directions, while reducing noise that is caused by a bottom surface echo. An element selecting circuit selects a group of a plurality of ultrasonic transducer elements for transmission from among ultrasonic transducer elements that constitute a two-dimensional array sensor so that the ultrasonic transducer elements for selected for transmission are arranged in line symmetry with respect to a first line symmetric axis to set the group selected for transmission. The element selecting circuit selects a group of a plurality of ultrasonic transducer elements for reception so that the ultrasonic transducer elements selected for reception are arranged in line symmetry with respect to a second line symmetric axis that is perpendicular to the first line symmetric axis to set the group selected for reception. A transmitting element selector selects, as transmitting elements, the ultrasonic transducer elements set by the element selecting circuit. A receiving element selector selects, as receiving elements, the ultrasonic transducer elements set by the element selecting circuit.

Claims

1. An ultrasonic measurement method using a two-dimensional array sensor that has a plurality of ultrasonic transducer elements two-dimensionally arranged and using a wave reflected from an inner portion of an object that is to be measured, comprising the steps of:

selecting a group of a plurality of ultrasonic transducer elements for transmission from among the ultrasonic transducer elements that constitute the two-dimensional array sensor so that the ultrasonic transducer elements selected for transmission are arranged in line symmetry with respect to a first line symmetric axis and setting the group selected for transmission, and selecting a group of a plurality of ultrasonic transducer elements for reception from among the ultrasonic transducer elements that constitute the two-dimensional array sensor so that the ultrasonic transducer elements selected for reception are arranged in line symmetry with respect to a second line symmetric axis that is perpendicular to the first line symmetric axis and passes through a rotationally symmetric axis and setting the group selected for reception;

transmitting an ultrasonic wave in the direction of the first line symmetric axis;

receiving an ultrasonic wave from the direction of the second line symmetric axis to store a signal reflected from the inner portion of the object; and

processing the reflected signal to inspect the object.

2. The ultrasonic measurement method according to claim 1, further comprising the steps of:

selecting a group of a plurality of ultrasonic transducer elements for transmission from among the ultrasonic transducer elements that constitute the two-dimensional array sensor so that the ultrasonic transducer elements selected for transmission are arranged in line symmetry with respect to a third line symmetric axis that is set by rotating the first line symmetric axis by a predetermined angle with respect to the rotationally symmetric axis, and selecting a group of a plurality of ultrasonic transducer elements for reception from among the ultrasonic transducer elements that constitute the two-dimensional array sensor so that the ultrasonic transducer elements selected for reception are arranged in line symmetry with respect to a fourth line symmetric axis that is perpendicular to the third line symmetric axis and passes through the rotationally symmetric axis;

transmitting an ultrasonic wave in the direction of the third line symmetric axis;

receiving an ultrasonic wave from the direction of the fourth line symmetric axis to store a signal reflected from the inner portion of the object; and

processing the reflected signal to inspect the object.

3. The ultrasonic measurement method according to claim 1, wherein,

the group of the ultrasonic transducer elements selected for transmission and the group of the ultrasonic transducer elements selected for reception are arranged so that when the groups are rotated about the rotationally symmetric axis by 90 degrees, the groups overlap each other.

4. The ultrasonic measurement method according to claim 1, further comprising the steps of:

setting a plurality of focal points to which ultrasonic waves are to be transmitted by the two-dimensional array sensor;

storing signals reflected from the focal points that are located in the inner portion of the object; and

processing the stored reflected signals to two-dimensionally or three-dimensionally image the inner portion of the object and display an image of the inner portion of the object.

5. The ultrasonic measurement method according to claim 4, further comprising the step of:

projecting three-dimensionally stored measurement data onto a flat plane and two-dimensionally displaying the data on an inspection result display screen.

6. The ultrasonic measurement method according to claim 5, further comprising the step of displaying information on a refraction angle φ

, an azimuth angle θ and

a reflected intensity I.

7. The ultrasonic measurement method according to claim 6, further comprising the step of specifying a range of the refraction angle φ

to be displayed.

8. The ultrasonic measurement method according to claim 1, further comprising the steps of:

performing either an operation for weighting a pulse voltage that is to be applied to each ultrasonic transducer element selected for transmission before the transmission of the ultrasonic wave or an operation for weighting a signal received when the ultrasonic wave is received; and

calibrating reflection data and a reflected intensity.

9. An ultrasonic measurement apparatus comprising:

a two-dimensional array sensor having a plurality of ultrasonic transducer elements two-dimensionally arranged;

a transmitting/receiving section that transmits an ultrasonic wave from each ultrasonic transducer element included in the two-dimensional array sensor to an object to be measured and receives a wave reflected from the object;

a controller that controls the transmitting/receiving section to generate three-dimensional or two-dimensional image data; and

a display unit that displays the three-dimensional or two-dimensional image data generated by the controller, wherein

the controller includes an element selecting section that selects a group of a plurality of ultrasonic transducer elements for transmission from among the ultrasonic transducer elements that constitute the two-dimensional array sensor so that the ultrasonic transducer elements selected for transmission are arranged in line symmetry with respect to a first line symmetric axis to set the group selected for transmission, and selects a group of a plurality of ultrasonic transducer elements for reception from among the ultrasonic transducer elements that constitute the two-dimensional array sensor so that the ultrasonic transducer elements selected for reception are arranged in line symmetry with respect to a second line symmetric axis that is perpendicular to the first line symmetric axis and passes through a rotationally symmetric axis to set the group selected for reception, and

the transmitting/receiving section includes a transmitting element selector and a receiving element selector, the transmitting element selector being adapted to select, as transmitting elements, the ultrasonic transducer elements set by the element selecting section, the receiving element selector being adapted to select, as receiving elements, the ultrasonic transducer elements set by the element selecting section.

10. The ultrasonic measurement apparatus according to claim 9, wherein

the controller includes either an amplitude adjusting section or a weighting section, the amplitude adjusting section being adapted to weight a pulse voltage that is to be applied to each ultrasonic transducer element selected for transmission before the transmission of the ultrasonic wave, the weighting section being adapted to weight a signal received when the ultrasonic wave is received.

11. An ultrasonic measurement apparatus comprising:

a two-dimensional array sensor having a plurality of ultrasonic transducer elements two-dimensionally arranged;

a transmitting/receiving section that transmits an ultrasonic wave from the two-dimensional array sensor and receives a wave reflected from an inner portion of an object that is to be measured; and

a controller that controls the transmitting/receiving section to cause the transmitting/receiving section to transmit the ultrasonic wave and receive the ultrasonic wave;

wherein the two-dimensional array sensor has an inner circumferential portion and an outer circumferential portion, the arrangement of the ultrasonic transducer elements included in the inner circumferential portion being different from the arrangement of the ultrasonic transducer elements included in the outer circumferential portion,

a distance between the gravity centers of each adjacent pair of the ultrasonic transducer elements included in the inner circumferential portion is equal to or less than a distance at which noise such as a grating lobe is caused,

a distance between the gravity centers of each adjacent pair of some of the ultrasonic transducer elements included in the outer circumferential portion is equal to or less than the distance at which noise such as a grating lobe is caused, and a distance between the gravity centers of each adjacent pair of the other ultrasonic transducer elements included in the outer circumferential portion is larger than the distance at which noise such as a grating lobe is caused,

the controller has an element selecting circuit that selects an element that is to be used from among the plurality of ultrasonic transducer elements that constitute the two-dimensional array sensor,

the element selecting circuit selects all the ultrasonic transducer elements included in the inner circumferential portion and ultrasonic transducer elements included in the outer circumferential portion so that a distance between the gravity centers of each adjacent pair of the selected transducer elements included in the outer circumferential portion, wherein the distance is measured in a transmitting and receiving direction obtained by projecting a direction in which an ultrasonic is transmitted and received onto a surface of the array sensor, is equal to or less than the distance at which noise is not caused.

12. The ultrasonic measurement apparatus according to claim 11, wherein

the element selecting circuit selects elements whose gravity centers are located in a rectangular region having a long side that extends in the projected transmitting and receiving direction and a short side whose length is equal to the diameter of the inner circumferential portion.

13. An ultrasonic sensor that transmits an ultrasonic wave and has a plurality of two-dimensionally ultrasonic transducer elements arranged, the ultrasonic sensor being used in an ultrasonic measurement apparatus that performs a measurement using a wave reflected from an inner portion of an object that is to be measured, comprising:

an inner circumferential portion and an outer circumferential portion in which the arrangement of the ultrasonic transducer elements included in the inner circumferential portion is different from the arrangement of the ultrasonic transducer elements included in the outer circumferential portion,

wherein a distance between the gravity centers of each adjacent pair of the ultrasonic transducer elements included in the inner circumferential portion is equal to or less than a distance at which noise such as a grating lobe is caused, and

a distance between the gravity centers of each adjacent pair of some of the ultrasonic transducer elements included in the outer circumferential portion is equal to or less than the distance at which noise such as a grating lobe is caused, and a distance between the gravity centers of each adjacent pair of the other ultrasonic transducer elements included in the outer circumferential portion is larger than the distance at which noise such as a grating lobe is caused.

14. An ultrasonic measurement method using a two-dimensional array sensor that has a plurality of ultrasonic transducer elements two-dimensionally arranged to transmit an ultrasonic wave and using a wave reflected from an inner portion of an object that is to be measured, comprising the steps of:

using the two-dimensional array sensor that has an inner circumferential portion and an outer circumferential portion, the arrangement of the ultrasonic transducer elements included in the inner circumferential portion being different from the arrangement of the ultrasonic transducer elements included in the outer circumferential portion, wherein a distance between the gravity centers of each adjacent pair of the ultrasonic transducer elements included in the inner circumferential portion is equal to or less than a distance at which noise such as a grating lobe is not caused, a distance between the gravity centers of each adjacent pair of some of the ultrasonic transducer elements included in the outer circumferential portion is equal to or less than the distance at which noise is not caused, and a distance between the gravity centers of each adjacent pair of the other the ultrasonic transducer elements included in the outer circumferential portion is larger than the distance at which noise is not caused; and

selecting all the ultrasonic transducer elements included in the inner circumferential portion and ultrasonic transducer elements that are adjacent to each other and included in the outer circumferential portion and whose gravity centers are separated with a distance that is equal to or less than the distance at which noise is not caused for the inspection of the object, the distance between the gravity centers of each adjacent pair of the selected elements included in the outer circumferential portion being measured in a direction obtained by projecting, onto the surface of the array sensor, a direction in which the ultrasonic wave is transmitted and received.

15. The ultrasonic measurement method according to claim 15, further comprising the steps of:

setting a plurality of focal points to which ultrasonic waves are to be transmitted by the two-dimensional array sensor;

selecting a range of elements to be used for transmission and reception of the ultrasonic waves to the focal points;

storing signals reflected from the focal points located in the inner portion of the object; and

processing the stored reflected signals to two-dimensionally or three-dimensionally image the inner portion of the object.