Ultrasonic methods and apparatus

Abstract

A method for determining information regarding a depth step of an object between a relatively shallow and a relatively deep part of the object, measured by an ultrasonic device that performs ultrasonic echo measurements from the front of the object, the method comprising: obtaining a set of measurement data of ultrasonic echoes that spread across the depth step of the object; and using the measurement data of ultrasonic step echoes generated by the depth step of the object within that set of measurement data of ultrasonic step echoes generated by the depth step of the object, to determine information regarding the depth step of the object.

Description

[Technical Field]

[0001] The present invention relates to a method for inspecting an object and related apparatus, and more particularly to an ultrasonic inspection apparatus for obtaining ultrasonic measurements of an object. [Background technology]

[0002] It is known to measure the quality and / or dimensions of manufactured objects to ensure they meet quality requirements / tolerances. For high-value components such as aerospace turbine blades, the external shape of an object can be measured to submicron accuracy using a surface-contact (or non-contact) probe mounted on a coordinate measuring machine (CMM). Examples of techniques for measuring the positions of multiple points on the surface of an object using a CMM with a surface-contact or non-contact probe are described in Patent Documents 1, 2, and 3.

[0003] In addition to surface measurements, it is often necessary to identify the thickness of a part, the internal characteristics / structure of an object, and / or internal faults, and ultrasonic testing equipment is known to be used for this purpose. Such ultrasonic testing equipment emits ultrasonic pulses that are projected onto the object being inspected, and the ultrasonic testing equipment records the echoes of the pulses. The time delay between the pulse echoes can provide valuable information about the object. Such a system can be called a “pulse-echo” ultrasonic testing equipment.

[0004] Known ultrasonic inspection devices include those that require the object to be inspected to be immersed in a liquid (e.g., water) and those that do not require the object to be submerged. In immersion systems, the liquid provides good acoustic coupling with the object, but the arrangement is expensive and complex, especially for large objects. An example of an ultrasonic immersion system is described in Patent Document 4. Ultrasonic inspection devices can be handheld, and how such devices can be attached to the quill of a positioning device such as a CMM has been described above. For example, Patent Documents 5 and 6 describe ultrasonic inspection devices attached to the quill of a CMM. An ultrasonic inspection device can be called an ultrasonic probe.

[0005] Patent Document 7 describes a method of calibrating an ultrasonic probe to determine the axis of its optimal signal (i.e., its "ultrasonic axis") so that the orientation of the probe can be determined to obtain a desired signal during object inspection.

[0006] Typically, an ultrasonic inspection device employs one of three well-known operating modes that can extract time-delay information from the measured ultrasonic signal. These different modes are typically called Mode-1, Mode-2, and Mode-3, respectively. In Mode-1, the time-delay measurement is performed between the initial excitation pulse and the first echo / reflection from the back-wall feature of the object. In Mode-2 measurement, the time-delay measurement is performed between the echo / reflection from the front surface of the object and the first echo from the back-wall feature of the object. In Mode-3 measurement, the time-delay measurement is performed between two or more consecutive echoes from the back-wall feature of the object.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Patent Document 9

Summary of the Invention

[0008] The present invention relates to an improved technique for finding information regarding a depth step of an object between a relatively shallow part and a relatively deep part of the object, measured by an ultrasonic inspection device that performs ultrasonic echo measurement from the front surface of the object.

[0009] According to a first aspect of the present invention, there is provided a method for determining information regarding a depth step of an object between a relatively shallow part and a relatively deep part of the object, measured by an ultrasonic inspection device that performs ultrasonic echo measurement from the front surface of the object, the method comprising: obtaining a set of measurement data of ultrasonic echoes that spreads across the depth step of the object; and determining information regarding the depth step of the object using the measurement data of ultrasonic step echoes generated by the depth step of the object in the set. Thus, put another way, the method comprises obtaining a set of measurement data of ultrasonic echoes that spreads across the depth step of the object, and determining information regarding the depth step of the object using the measurement data of ultrasonic step echoes within the set (where the measurement data of ultrasonic step echoes includes the measurement data of ultrasonic echoes generated by the step).

[0010] To understand, a set of measurement data from ultrasound echoes that spread across a depth difference in an object is, (i) Measurement data of (normal / non-step) ultrasonic posterior wall echoes generated by the relatively shallow portion on the first side of the step, and / or (ii) Measurement data of (normal / non-step) ultrasonic posterior wall echoes generated by the relatively deep portion on the second side of the step, and (iii) Measurement data of ultrasonic step echo generated by the step in depth of the object, It can include...

[0011] Therefore, the method of the invention can be said to include, within the set, identifying measurement data of ultrasonic step echoes generated by a step in the depth of the object, and using the identified measurement data of ultrasonic step echoes to determine information regarding the step in the depth of the object.

[0012] The inventors identified the presence of such ultrasonic step echoes (generated by such steps in the depth of an object) (among normal / non-step ultrasonic back wall echoes) and identified that information about the step can be determined using such ultrasonic step echoes. In particular, such step echoes are useful for determining the location of the step, but can also be used to determine other information about the step, such as the sum of the thicknesses of the relatively shallow and relatively deep portions. Measurement data of such step echoes can also be used to determine information about the shape of the step, for example, from the relative amplitudes of the main step echo (described below), the first generation back wall echo of the relatively shallow portion, and the first generation back wall echo of the relatively deep portion of the echo. Furthermore, the step can also be compared to the nominal (or reference) data / object step by comparing the measurement data of the object's step echo with the measurement data of a nominal step echo (or the measurement data of a reference object's step echo).

[0013] As can be understood, the measurement data of an ultrasonic posterior wall echo may include and / or be derived from the measured echo of the ultrasonic signal emitted by the ultrasonic device, as detected by the ultrasonic device. The measurement data of an ultrasonic posterior wall echo may be derived from the measured ultrasonic energy received by the ultrasonic device, which has been reflected and / or diffracted by features within the object (e.g., relatively shallow parts of the object, relatively deep parts of the object, or both relatively shallow and relatively deep parts in the case of step echoes). In particular, the measurement data of an ultrasonic posterior wall echo may include and / or be derived from the measured arrival time of the echo of the ultrasonic signal emitted from the ultrasonic device. Thus, a set of ultrasonic posterior wall echo measurement data may include a set of arrival times of the measurement data. In other words, a set of measurement data for ultrasonic echoes spreading across a depth step in an object may include data representing: i) the arrival time of echoes reflected and / or diffracted by the relatively shallow portion of the object; ii) the arrival time of echoes reflected and / or diffracted by the relatively deep portion of the object; and iii) the arrival time of echoes reflected and / or diffracted by both the relatively shallow and relatively deep portions of the object.

[0014] The inventors believe that the most useful step echo is obtained when the time to reach the ultrasound device is ToA(BW 1s )+ToA(BW 1d ) is approximately equal to the arrival time (where ToA(BW 1s ) is the time it takes for the first generation of ultrasound echoes generated by the relatively shallow portion to reach the ultrasound device, and ToA(BW 1d) is the arrival time of the first-generation ultrasonic echo generated by the relatively deep part to the ultrasonic inspection device), and it was identified that it could be a step echo particularly useful for determining information regarding the step. Such a step echo may be referred to as "Primary Step-Echoes". In particular, as will be described in more detail below in relation to specific embodiments, such "Primary Step-Echoes" may have a larger amplitude compared to other "Subordinate Step-Echoes" generated by the step in the depth of the object. As described above, the most useful step echo is the step echo whose arrival time is approximately equal to the arrival time of ToA(BW 1s ) + ToA(BW 1d ). In this context, this means a step echo that arrives within the time frame of 0.75(ToA(BW 1s ) + ToA(BW 1d )) to 1.25(ToA(BW 1s ) + ToA(BW 1d )), more preferably, within the time frame of 0.8(ToA(BW 1s ) + ToA(BW 1d )) to 1.2(ToA(BW 1s ) + ToA(BW 1d )), and particularly preferably, within the time frame of 0.85(ToA(BW 1s ) + ToA(BW 1d )) to 1.15(ToA(BW 1s ) + ToA(BW 1d )).

[0015] The method can include identifying measurement data of ultrasonic step echoes generated by the step in the depth of the object from a set of measurement data of ultrasonic echoes spreading across the step in the depth of the object. Next, the method can include determining information regarding the step in the depth of the object using the identified measurement data of the ultrasonic step echoes.

[0016] As understood, an ultrasonic echo measurement may include a measurement of the signal received by the ultrasound apparatus over a period of time after the emission of an ultrasonic pulse to an object. Optionally, in embodiments in which the ultrasound apparatus includes a delay line, the ultrasonic echo measurement may be a measurement of the signal received by the ultrasound apparatus between the echo of a first delay line (DL1) and the echo of a second delay line (DL2) (i.e., the first and second echoes generated by the delay line of the ultrasound apparatus). As understood, the delay line may include a gap (e.g., a fluid gap) between the transducer (which emits and detects ultrasonic energy / ultrasonic pulses and their echoes) and the front surface of the object, and / or may include a rigid or deformable coupling element. As understood, some ultrasound apparatuses are configured such that, during measurement, the transducer (which emits and detects ultrasonic energy / ultrasonic pulses and their echoes) is in direct contact with the front surface of the object, in which case there is no delay line. As understood, a measurement of the signal received by an ultrasonic probe may be a measurement of the ultrasonic energy received by the ultrasonic probe (e.g., a measurement of the amplitude of the ultrasonic energy).

[0017] The set of ultrasonic echo measurement data may be, for example, historical ultrasonic echo measurement data acquired by the ultrasonic device at a different time than the execution of the method of the present invention. Therefore, the method may include receiving / acquiring a set of ultrasonic echo measurement data from a storage device, an input device, and / or a remote device. Optionally, the method may include the step of using the ultrasonic device to acquire a set of ultrasonic echo measurement data spread across a depth step of an object. Thus, the set of ultrasonic echo measurement data may be current / live ultrasonic echo measurement data. The ultrasonic device may be calibrated (for example, prior to or as part of the method of the present invention). In particular, the ultrasonic device may be calibrated so that the position of its contact surface is known within the positioning volume of a positioning device. In particular, the ultrasonic probe may be calibrated so that the position of the ultrasonic axis is known within the positioning volume of a positioning device. The ultrasonic device may be calibrated so that the orientation of the ultrasonic axis is known (for example, using a technique such as that described in Patent Document 7).

[0018] As is understood, ultrasonic energy / pulses can be emitted by the same ultrasound device that detects ultrasonic echoes. A set of measurement data for ultrasonic echoes can be acquired by a "pulsed echo" ultrasound device. Optionally, the ultrasound device used to acquire the measurement data set for ultrasonic echoes comprises a single transducer for emitting and detecting ultrasonic energy / ultrasonic pulses and their echoes.

[0019] Ultrasonic step echo measurement data may be the result of ultrasonic echoes received by an ultrasonic testing device, which are reflected and / or diffracted by both the relatively shallow and relatively deep parts of an object. In particular, ultrasonic step echo measurement data may be the result of ultrasonic echoes received by an ultrasonic testing device, which are first reflected by the rear wall features of one of the relatively shallow or relatively deep parts of the object, then reflected by the front, and then reflected by the rear wall features of the other of the relatively shallow or relatively deep parts.

[0020] The method may include identifying peaks in the step echo measurement data. The method may also include using the information about the peaks to determine information about the step.

[0021] As described above, the present invention has proven particularly useful in determining information regarding the location of steps. Therefore, such information may include positional information. In other words, the step of determining information regarding depth steps of an object using the measurement data of the ultrasonic step echo may include determining information regarding the position / location of depth steps of an object using the measurement data of the ultrasonic step echo. For example, the method of the present invention can be used to determine information regarding the lateral position / location of a step (e.g., relative to the front of the object) (e.g., in a direction parallel to the front of the object). This is in contrast to the depth / height position of a step, which is measured in a dimension perpendicular to the front of the object. As can be understood, such depth / height position of a step can be inferred from known techniques for determining the depth of back wall features, for example, the depth of the edge of a step can be estimated to be the same as the depth of the back wall feature immediately adjacent to the edge of the step. Thus, while ultrasonic inspection devices have conventionally been used to determine information regarding the depth / height of features of an object, the present invention uses an ultrasonic inspection device to determine information regarding the position of steps of a part in a dimension perpendicular to conventional depth / height measurements.

[0022] The format of the information regarding the (lateral) position / location of the step can be determined according to the requirements of the end user. For example, this information may include / identify which ultrasound measurement (or a suitable subset of ultrasound measurements) within a set of ultrasound measurement data best indicates that the depth step of the object is aligned with / located across the step (e.g., the one with the strongest ultrasound step echo measurement data). For example, if the set of ultrasound measurement data is obtained by ultrasound measurements (e.g., "pings") at multiple different points P along a line L (e.g., a given inspection line) or at multiple different points P within a region A (e.g., a given inspection region), the method of the present invention can return at which point along the line L or at which point within A (or a suitable subset of the set of ultrasound measurements) the depth step of the object is determined.

[0023] The position information may include coordinate position information relating to the position of the depth step of the part. In other words, information regarding the (lateral) position of the step may take the form of coordinate position information (e.g., Cartesian or non-Cartesian coordinates), such as the X position or X,Y position of the depth step of the object. If necessary, the information regarding the lateral position of the step can be combined with information regarding the height of the depth step of the object to determine the three-dimensional position of the edge of the step (therefore, the method may further include determining the information regarding the height of the depth step of the object, for example, from the same set of ultrasonic echo measurement data and / or from different sets of ultrasonic echo measurement data).

[0024] Advantageously, the method may include combining information about the depth step of an object (e.g., location information) with other known or assumed information about the object. For example, the method may include combining information about the depth step of an object (e.g., location information) with other information determined by inspection of the object on the same or a different positioning device (e.g., the same or a different coordinate positioning device). For example, such “other information” may be determined by contact or non-contact dimensional measurement of the object (e.g., contact or non-contact dimensional measuring probes such as touch trigger probes or scanning probes). Thus, for example, the method may include combining coordinate location information about the depth step of an object with coordinate location information about at least one other feature of the object (e.g., so that information about the location of the depth step of an object can be determined / evaluated for one or more other features of the object).

[0025] A set of ultrasonic echo measurement data can include ultrasonic measurement data obtained from a set of points on the front surface of an object. The set of ultrasonic echo measurement data / points can extend in only one dimension (e.g., along a straight line) or in two dimensions (e.g., covering an area) relative to the front surface of the object. The method can include determining the location / position of the step in a dimension parallel to the extent over which the set of measurement data / points extends. Thus, the method can include determining the location / position of the step in a dimension parallel to the shape of the front surface. As can be understood, if the front surface of an object is a plane, the method can include determining the location / position of the step in a dimension parallel to the plane of the front surface.

[0026] As is understood, an ultrasonic inspection device used to acquire measurement data of an ultrasonic echo may include a coupling element for engaging with the surface of the object being inspected (as is understood, this is not mandatory, and coupling elements are usually absent in immersion systems, for example). The coupling element may be deformable. In other words, the coupling element may be a soft coupling element (rather than a rigid / hard coupling element). For example, the coupling element may include an elastomer. For example, the coupling element may include a polymer, such as a superabsorbent polymer. The coupling element may be moistened with a lubricant, for example. Any suitable lubricant may be used. The coupling element may include a self-lubricating material. A self-lubricating material preferably releases a lubricant such as water and / or oil from its outer surface in a controlled manner. A self-lubricating material may include a lipophilic elastomer. Advantageously, a self-lubricating material may include a hydrophilic elastomer. For example, hydrophilic elastomers may include lightly crosslinked hydrophilic vinyl elastomers or non-compressible gelatinous hydrophilic elastomer materials such as superabsorbent polymer hydrogels, such as sodium polyacrylate.

[0027] In a preferred embodiment of the present invention, a set of measurement data for ultrasonic echoes is acquired by an ultrasonic inspection device attached to a positioning device, such as a coordinate positioning device. The positioning device may be a manually operated positioning device, but preferably includes, for example, one or more motors for automatic operation under control, or one or more processing devices (e.g., machine control devices). In a preferred embodiment, the coordinate positioning device includes a coordinate measuring machine (CMM), a machine tool, a robot, or an arm. The coordinate positioning device may be a positioning device in a Cartesian coordinate system (e.g., bridge type) or a positioning device in a non-Cartesian coordinate system (e.g., hexapod type). The positioning device can facilitate relative translational motion between the ultrasonic inspection device and the object in at least two linear degrees of freedom. The positioning device can facilitate relative rotational motion between the ultrasonic inspection device and the object about at least one axis of rotation.

[0028] The ultrasound apparatus can be mounted on an articulated member having at least one rotation axis, and optionally two (preferably orthogonal) rotation axes. The articulated member may be a series of continuously connected articulated members. Optionally, the articulated member may include an indexed articulated member (for example, the articulated member has a certain number of discrete postures that can fix the articulated member). The articulated member may include at least one motor for controlling the posture of the ultrasound apparatus about at least one axis.

[0029] The joint members can be attached to members of a coordinate positioning device that are movable along at least two linear degrees of freedom, and preferably to members of a coordinate positioning device that are movable along three orthogonal degrees of freedom. In the case of a bridge-type CMM, such members are generally called "quills" or "Z-columns." Thus, the ultrasound machine can be attached to a device commonly referred to in the art as a 5-axis coordinate positioning device. If necessary, the object itself can also be attached so as to be linearly and / or rotatably movable, for example, to a rotary table.

[0030] The ultrasound device may include a main body on the distal side of the coupling element. In other words, the ultrasound device may include a main body at a first end and a coupling element at a second end. The ultrasound device can be attached to a positioning device via the main body. The ultrasound device (e.g., the main body) and the positioning device (e.g., the articulated member / rotating head) may include corresponding mounting features that enable the ultrasound device to be attached to the positioning device, which in particular enables the ultrasound device to be automatically attached to or detached from the positioning device. In other words, it is preferable that the ultrasound device is automatically interchangeable on the positioning device, for example, from rack to rack located within the working space of the positioning device. The ultrasound device (e.g., the main body) and the positioning device may include complementary features of a repeatable mount, for example, complementary features of a kinematic mount. At least one of the ultrasound device and the positioning device may include at least one magnet for holding the ultrasound device to the positioning device.

[0031] The ultrasound imaging apparatus itself may include at least one processing unit for analyzing / processing the signal received by the ultrasonic transducer, for example, determining time delay information. Alternatively, the signal received by the ultrasonic transducer may be analyzed / processed by a processing unit outside the imaging apparatus (e.g., using an external interface or an offline computer).

[0032] To ensure understanding, the terms “processor” and “processing component” used herein are intended to include not only custom-configured processing units (e.g., field-programmable gate arrays “FPGAs”) but also more general-purpose processing units that can be programmed (e.g., via software) according to the needs of the application in which they are used. Therefore, suitable processing units include, for example, CPUs (central processing units), FPGAs (field-programmable gate arrays), and ASICs (application-specific integrated circuits).

[0033] An ultrasound inspection device may include at least one transducer for emitting ultrasonic energy / ultrasonic pulses. An ultrasound inspection device may include at least one transducer for detecting echoes of the emitted ultrasonic energy / pulses. Optionally, an ultrasound inspection device may include at least one transducer for emitting ultrasonic pulses and at least one transducer for detecting ultrasonic pulses. Optionally, the at least one transducer for emitting ultrasonic pulses is the same sensor used to detect the ultrasonic pulses. In other words, an ultrasound inspection device may include a single transducer that performs both emission and detection of ultrasonic pulses. The transducer may include a piezoelectric element. Preferably, the transducer excites longitudinal sound waves (L waves). An ultrasound inspection device may include a single-channel inspection device. For example, an ultrasound inspection device may include only one active element / transducer that performs pulse-echo operation. Optionally, an ultrasound inspection device may include a phased array inspection device.

[0034] Ultrasound equipment can excite and receive ultrasound in any known way. Ultrasound equipment can operate at high frequencies. For example, the operating frequency can be 5 MHz or higher, 10 MHz or higher, or more preferably 15 MHz or higher. In one embodiment, the operating frequency is about 20 MHz. Higher frequencies (e.g., 15 MHz or higher) are particularly useful for ultrasound equipment with deformable tips, and have been shown to enable particularly high-resolution measurements. In ultrasound equipment with deformable tips, it has been found that lower frequencies can generate more noise.

[0035] The method may further include using measurement data of ultrasonic echoes obtained from the front to determine information regarding at least one of the following in the relatively shallow and / or relatively deep parts of the object: thickness / depth, material structure (e.g., porosity or density, crystal morphology and / or orientation), or sound velocity. Such measurement data of ultrasonic echoes may be obtained by the same ultrasonic device used to obtain the set of measurement data of ultrasonic echoes used to determine information regarding depth steps in the object, or by a different ultrasonic device. Optionally, at least a portion of the ultrasonic echo data used to determine information regarding depth steps in the object may also be used to determine information regarding at least one of the following in the relatively shallow and / or relatively deep parts of the object: thickness / depth, material structure (e.g., porosity or density, crystal morphology and / or orientation), or sound velocity.

[0036] According to a second aspect of the present invention, a method is provided for determining information regarding the difference in depth of an object between a relatively shallow portion and a relatively deep portion, measured by an ultrasonic inspection device that performs ultrasonic echo measurement from the front surface of the object, wherein the method is: (i) Measurement data of the ultrasonic posterior wall echo generated by the relatively shallow portion on the first side of the step, and / or (ii) Measurement data of the ultrasonic posterior wall echo generated by the relatively deep portion on the second side of the step, (iii) Measurement data of ultrasonic step echo generated by the step in depth of the object, To obtain a set of measurement data including ultrasound posterior wall echo, Within that set, the measurement data of ultrasonic step echoes generated by the depth difference of the object is identified, Using the measurement data of the identified ultrasonic step echo, information regarding the step in depth of the object is determined, Includes.

[0037] According to a third aspect of the present invention, a method is provided for inspecting an object having a step in depth between a relatively shallow part and a relatively deep part of the object, measured by an ultrasonic inspection device that performs ultrasonic echo measurements from the front surface of the object, wherein the time it takes for the ultrasonic step echo measurement data to reach the ultrasonic inspection device is calculated from a set of ultrasonic echo measurement data that spreads across the step in depth of the object. 1s )+ToA(BW 1d The arrival time is approximately equal to the arrival time of ToA(BW 1s ) is the time it takes for the first generation of ultrasound echoes generated by the relatively shallow portion to reach the ultrasound examination device, and ToA(BW 1d This includes identifying / using measurement data of an ultrasonic step echo, which is the time it takes for the first generation of ultrasonic echoes generated by the relatively deep portion to reach the ultrasound apparatus. As understood, the features described above in relation to the first aspect of the present invention are equally applicable to this aspect of the present invention.

[0038] A fourth aspect of the present invention provides a method for determining information regarding a depth step of an object between a relatively shallow portion and a relatively deep portion of the object, measured by an ultrasonic inspection apparatus including a single transducer that emits and detects ultrasonic energy to perform an ultrasonic echo measurement from the front of the object, the method comprising: using the single transducer to emit and detect ultrasonic energy to obtain a set of measurement data of ultrasonic echoes that spread across the depth step of the object; and using the measurement data of ultrasonic step echoes generated by the depth step of the object therein to determine information regarding the depth step of the object.

[0039] According to a fifth aspect of the present invention, a computer program code is provided which, when executed by a processor device, includes instructions configured to cause the processor device to perform any of the methods described above. According to a sixth aspect of the present invention, a computer-readable medium is provided which holds the above-described computer program code.

[0040] According to a seventh aspect of the present invention, an apparatus is provided comprising at least one processor device configured to receive a set of measurement data of ultrasonic echoes spreading across a depth step of an object, and to determine information regarding the depth step of the object using measurement data of ultrasonic step echoes generated by the depth step of the object. As can be understood, the features described above in relation to the above aspects of the present invention are also applicable to this aspect of the present invention. [Brief explanation of the drawing]

[0041] Herein, embodiments of the present invention will be described simply by reference to the following drawings. [Figure 1a] Figure 1a is a schematic diagram illustrating the basic operating principle of an exemplary ultrasound examination device. [Figure 1b] Figure 1b is a schematic diagram illustrating the basic operating principle of an exemplary ultrasound examination device. [Figure 1c] Figure 1c is a schematic diagram illustrating the basic operating principle of an exemplary ultrasound examination device. [Figure 2] Figure 2 shows an exemplary signal received by an ultrasound examination device performing ultrasound echo measurements. [Figure 3] Figure 3 shows an ultrasonic inspection device attached to a coordinate measuring machine (CMM). [Figure 4] Figure 4 shows various mechanical components of an ultrasonic testing device. [Figure 5a] Figure 5a is a schematic diagram showing the echoes received by an ultrasound inspection device when performing ultrasonic echo measurements on an object with a step in thickness at different inspection locations. [Figure 5b] Figure 5b is a schematic diagram showing the echoes received by an ultrasound inspection device when performing ultrasonic echo measurements on an object with a step in thickness at different inspection locations. [Figure 5c] Figure 5c is a schematic diagram showing the echoes received by an ultrasound inspection device when performing ultrasonic echo measurements on an object with a step in thickness at different inspection locations. [Figure 5d] Figure 5d is a schematic diagram showing the echoes received by an ultrasound inspection device when performing ultrasonic echo measurements on an object with a step in thickness at different inspection locations. [Figure 5e] Figure 5e schematically shows the echoes received by an ultrasound inspection device when performing ultrasonic echo measurements on an object with a step in thickness at different inspection locations. [Figure 5f] Figure 5f is a schematic diagram showing the echoes received by an ultrasound inspection device when performing ultrasonic echo measurements on an object with a step in thickness at different inspection locations. [Figure 5g] Figure 5g is a schematic diagram showing the echoes received by an ultrasound inspection device when performing ultrasonic echo measurements on an object with a step in thickness at different inspection locations. [Figure 5h] Figure 5h is a schematic diagram showing the echoes received by an ultrasound inspection device when performing ultrasonic echo measurements on an object with a step in thickness at different inspection locations. [Figure 6a] Figure 6a is a schematic diagram illustrating various methods used to acquire measurement data from ultrasound echoes. [Figure 6b] Figure 6b is a schematic diagram illustrating various methods used to acquire measurement data from ultrasound echoes. [Figure 6c] Figure 6c is a schematic diagram illustrating various methods used to acquire measurement data from ultrasound echoes. [Figure 6d] Figure 6d is a schematic diagram illustrating various methods used to acquire measurement data from ultrasound echoes. [Figure 7a] Figure 7a is a chart showing measurement data of ultrasonic echoes spreading across the step of the object in Figure 5. [Figure 7b] Figure 7b is a chart showing measurement data of ultrasonic echoes spreading across the step of the object in Figure 5. [Figure 8a] Figure 8a shows another example of an object with a step in depth. [Figure 8b]Figure 8b is a chart showing measurement data of ultrasonic echoes spreading across the step of the object in Figure 8a. [Figure 8c] Figure 8c is a chart showing measurement data of ultrasonic echoes spreading across the step of the object in Figure 8a. [Figure 9] Figure 9 is a flowchart illustrating an exemplary process for determining the location of a step in the thickness of an object measured by an ultrasonic probe, according to the present invention. [Figure 10] Figure 10 is a flowchart illustrating an exemplary process for identifying measurement data of ultrasonic step echoes generated by depth differences in a component. [Figure 11] Figure 11 schematically shows a step echo generated by the diffraction of ultrasonic energy due to a step in an object. [Figure 12a] Figure 12a schematically illustrates how the depth step of an object, measured by an ultrasonic probe, is generated not only by the change in thickness between the front and back surfaces of the object, but also by different types of features of the object. [Figure 12b] Figure 12b schematically illustrates how the depth step of an object, measured by an ultrasonic probe, is generated not only by the change in thickness between the front and back surfaces of the object, but also by different types of features of the object. [Figure 12c] Figure 12c schematically illustrates how the depth step of an object, measured by an ultrasonic probe, is generated not only by the change in thickness between the front and back surfaces of the object, but also by different types of features of the object. [Modes for carrying out the invention]

[0042] Referring to Figures 1 and 2, the basic operating principle of an exemplary ultrasonic inspection apparatus will be explained. Figure 1a shows an ultrasonic inspection apparatus 2 (hereinafter referred to as the ultrasonic probe), including an external body 4. It is equipped with an ultrasonic wave / pulse transducer, which includes a piezoelectric element 6 (or an equivalent element such as a laser ultrasonic transducer) and a deformable coupling element 8. As can be understood, other components commonly used in ultrasonic probes, such as a backing layer and a matching layer (waveplate), may constitute part of the ultrasonic probe, but are not shown in Figure 1a for simplification. To measure the thickness of an object 10 (or the depth of internal features), the probe 2 and / or the object 10 are moved so that the deformable coupling element 8 and the front surface 9 of the object 10 engage. When an excitation pulse is applied to the piezoelectric element 6, an ultrasonic pulse 12 is irradiated onto the object 10. As schematically shown, this ultrasonic pulse 12 is reflected off the rear surface 11 of the object (or an internal feature between the front surface 9 and the rear surface 11), and this reflected echo is detected by an ultrasonic probe (e.g., via a piezoelectric element 6), and this reflected echo is generally called a rear wall echo (regardless of whether it came from the rear surface or an internal feature). This process can be called pulse echo measurement, or more colloquially, "pinging". As understood, the measurement and estimation of thickness / depth can be performed using time-of-flight measurement or time-delay measurement of the irradiated ultrasonic waveform.

[0043] Figure 2 shows an example of an ultrasonic signal / waveform received and output by the transducer's active piezoelectric element 6 in response to a transient high-voltage excitation pulse being applied to the piezoelectric element 6. This time-domain waveform is called an "A-scan" plot, but to suppress random, uncorrelated electronic noise, it can be a time-averaged response from a sequence of such excitation pulses (e.g., a sequence of N pulses, where N is at least 2, but a suitable range for N is 16-32).

[0044] The initial excitation pulse generated by the piezoelectric element 6 is labeled "Tx-Pulse" in Figure 2. This initial excitation pulse propagates the check wave to the coupling element 8 (which functions as a delay line), and then propagates at the speed of sound within the coupling element material (CL). The first reflection / echo peak (DL1) received by the piezoelectric element 6 is generated by sound wave reflection from the front surface 9 of object 10. It can be seen that this reflection / echo from the front surface 9 of object 10 (i.e., the DL1 echo) occurs considerably later than when the initial transmission pulse (Tx-pulse) has completely decayed.

[0045] Although some ultrasonic energy is reflected from the front 9 and does not enter the object 10, a sufficient proportion of ultrasonic energy is transmitted to the object 10 as a measurable inspection pulse, enabling subsequent thickness / depth measurement. The speed of sound within the deformable coupling element 8 may be slower than the speed of sound within the object 10, and especially if the object is relatively thin (or the depth of the internal features is relatively shallow), multiple reflections / echoes may occur from the rear surface 11 of the object 10 before the second reflection / echo peak (DL2) from the delay line / coupling element 8 is recorded by the transducer. For example, the “A-scan” plot in Figure 2 shows the first, second, and third generation rear wall echoes BW1, BW2, and BW3, which are schematically shown in Figure 1b.

[0046] As schematically shown in Figure 1c, since ultrasonic energy is irradiated onto the object 10 across the entire width of the coupling element 8 and received from the object 10, each point on the coupling element 8 can be considered a discrete, individual ultrasonic emission and reception point. Figure 1b schematically shows one such emission point and the corresponding first, second, and third generation posterior wall echoes BW1, BW2, and BW3 detected by the ultrasonic probe 8. Figure 1c shows that multiple such situations actually exist. For the sake of clarity, Figure 1c shows only two emission points and their corresponding first, second, and third generation posterior wall echoes BW1, BW2, and BW3, but as can be understood, similar emission points also exist between the two emission points shown and their corresponding posterior wall echoes. Also as can be understood, radiation is emitted from the emission point in multiple directions on the hemisphere, not just in the directions indicated by the arrows in Figures 1b and 1c.

[0047] Figures 1b and 1c show the presence of first, second, and third-generation posterior wall echoes, but as can be understood, the number of posterior wall echoes received varies depending on various factors, such as the depth of the cross-section of the object being measured.

[0048] Referring to Figure 3, an ultrasonic probe 2 attached to a positioning device 200 is shown. This positioning device comprises a moving structure in the form of a coordinate measuring machine (CMM) in this case. The CMM 200 comprises a base 202 supporting a frame 204, the frame 204 holding a carriage 206, the carriage 206 holding a quill 208 (or "Z column"). A motor (not shown) is provided to move the quill 208 along three mutually orthogonal axes X, Y, and Z (for example, by moving the frame 204 along the Y axis, the carriage 206 along the X axis, and the quill 208 along the Z axis).

[0049] In the embodiment described, the ultrasonic probe 2 is mounted to a positioning device 200 (e.g., on a quill 208) via an articulated head 210 that rotates the ultrasonic probe 2 around two rotation axes D and E. However, as can be seen, this is not necessarily required, and the ultrasonic probe 2 can be mounted to the positioning device 200 via a fixed, non-rotating head. The articulated head 210 may be an indexing head or a continuous head (e.g., a REVO® head from Renishaw plc). As can be seen, a continuous head can orient the device mounted on it at substantially any angle around at least one axis, and in many cases provides a nearly infinite number of angular directions. Also, if necessary, the orientation of the measuring device around the axis of a continuous head can be changed during measurement (e.g., while the contact probe is in contact with the object being inspected to acquire measurement information). An indexing head, on the other hand, has a discrete number of defined ("indexed") positions on which the measuring device mounted on it can be fixed. With an indexing head, the orientation of the measuring device can be changed, but not while acquiring measurement data.

[0050] In this embodiment, the articulated head 210 facilitates the rotation of the probe 2 mounted thereon around the first and second rotation axes D and E via appropriate bearings and a motor (not shown).

[0051] The combination of the two rotational axes (D, E) provided by the joint head 210 and the three linear axes (X, Y, Z) of the CMM200 allows the ultrasound probe 2 to be moved / positioned with five degrees of freedom (two rotational degrees of freedom and three linear degrees of freedom).

[0052] Furthermore, although not shown, measuring encoders may be provided to measure the relative positions of each component of the base 202, frame 204, carriage 206, quill 208, and articulated head 210, thereby enabling the determination of the position of the measuring probe 2 relative to the workpiece 10' placed on the base 202.

[0053] The controller 220 is provided to control the operation of the CMM 200, such as controlling the position and orientation of the ultrasonic probe within the volume of the CMM (manually, for example, via an input device such as a joystick 216, or automatically, for example, under the control of an inspection program), and to receive information (e.g., measurement information) from the CMM 200. A display device 218 may be provided to assist user interaction with the controller 220. The controller 220 may be, for example, a dedicated electronic control system and / or can be configured as a personal computer.

[0054] As shown in the figure, for example, the controller 320 can be provided with a probe interface 150 (for facilitating communication with the ultrasonic probe 2).

[0055] Here, an exemplary ultrasonic probe 2 will be described in more detail with reference to Figure 4. The ultrasonic probe 2 comprises a base module including a main body 3, which is located at the proximal end of the probe 2 to be attached to a positioning device / CMM. The main body 3 may include electronic equipment necessary for supplying power to the probe, as well as for communicating control data and activation commands (e.g., for scheduling ultrasonic measurements). Power and / or control data, including ultrasonic data and thickness measurement results, may be transmitted via a communication channel and / or wirelessly on the rotating head. Instead of being supplied via the CMM, power may also be supplied, for example, from a battery located in the main body 3.

[0056] An elongated tube 5 (e.g., a rigid carbon fiber tube) extends from the main body 3 along the axial direction of the probe. The coupling element 8 is positioned at the distal end of the tube 5 from the main body 3. In this embodiment, the coupling element 8 is a deformable coupling element (useful when the ultrasonic probe is to be engaged with the surface of the object being inspected at different angles), but is not necessarily required, and the coupling element may be rigid. In this embodiment, the coupling element 8 comprises a hydrophilic elastomer. Optionally, the coupling element 8 is replaceable (e.g., can be attached with screws or snap-fits). Optionally, as in this embodiment, at least the portion of the coupling element 8 protruding from the tube 5 may be spherical. As understood, the coupling element engages with the wear plate of the transducer in the probe, and the coupling element 5 can serve as both a coupling element and a delay line. The coupling element 5 may be flexible and elastic so as to easily conform to the surface of the object 10' to which it engages.

[0057] During use, the ultrasonic probe 2 is moved by the CMM 200, and an acoustic coupling is formed with the object 10' by the coupling element 8 contacting the front surface 9 of the object 10' being inspected. The ultrasonic probe 2 generates ultrasonic pulses / waves (e.g., via a piezoelectric element, e.g., a laser ultrasonic transducer), which are irradiated onto the object 10' and reflected by the internal features or rear surface 11 of the object 10' to generate a "rear wall echo." The rear wall echo is detected and recorded by the ultrasonic probe 2 / controller 220.

[0058] An ultrasonic testing apparatus can excite and receive ultrasound by known methods. The ultrasonic testing apparatus can operate at high frequencies. For example, the operating frequency may be 5 MHz or higher, 10 MHz or higher, and more preferably 15 MHz or higher. In a preferred embodiment, the operating frequency is about 20 MHz. A transducer including a piezoelectric element preferably excites longitudinal sound waves (L waves).

[0059] Figure 5 shows the depth D of object 10'. d A relatively thick / deep portion having depth D sFigure 5 shows a cross-sectional view of an object 10' having a step S in thickness between a relatively thin / shallow portion. Figure 5a schematically shows an ultrasonic echo measurement performed in the relatively shallow portion of object 10'. Figure 5c schematically shows an ultrasonic echo measurement performed in the relatively deep portion of object 10'. Figure 5b schematically shows an ultrasonic echo measurement performed near the depth step S of object 10'. In Figure 5, for simplification, only the coupling element 8 of the ultrasonic probe 2 is shown.

[0060] As shown in Figures 5a and 5c, when the ultrasonic probe 2 is located away from the step S, the ultrasonic echo is formed only by the shallow or deep portion of object 10'. Therefore, the measurement data of the ultrasonic echo acquired at these positions is typical of what is normally associated with ultrasonic echo measurements. For example, as described above in relation to Figure 2, the delay line echo DL # During this time, one or more equally spaced posterior wall echoes BW detected by the ultrasound probe # This includes data showing the following. For example, as shown in Figure 5a, an ultrasound probe that performs ultrasound echo measurements in shallow areas has multiple generations (10 in this embodiment) of posterior wall echoes (in Figure 5a, the first (BW 1s ), 2nd (BW 2s ), and the third (BW 3s It detects and collects data representing the first generation of echoes (where the generation of echoes is explicitly indicated). Similarly, as shown in Figure 5c, an ultrasound probe performing ultrasound echo measurements in the deep part detects the first generation of posterior wall echoes (BW). 1d , second-generation posterior wall echocardiography (BW) 2d , and third-generation posterior wall echo BW 3dThe data representing this is detected and collected. As can be understood, since ultrasonic energy travels a longer distance in deeper parts than in shallower parts, the time to arrival (ToA) of the echo in deeper parts is longer than that of the echo in shallower parts. This is visualized in Figures 7a and 7b, which show plots of the amplitude / intensity of the echo signal received at a specific time to arrival (after ultrasonic pulse generation) for multiple different locations along the x-axis where the ultrasonic measurement was performed. As can be understood, the envelope amplitude can be determined using signal processing techniques such as the Hilbert transform, for example.

[0061] As shown in Figure 5b, when the ultrasonic probe is positioned near a step S, a “step echo” is formed, which is an echo generated by the step S at a depth of 10' of the object. In this particular example, at the illustrated position, there are two step echoes generated and detected by the ultrasonic probe: a “primary step echo” (PSE) and a “secondary step echo” (SSE).

[0062] The primary step echo (PSE) is primarily the result of ultrasonic energy emitted from the ultrasonic probe, which is reflected by the back wall (in this case, the shallow part) of the object on the first side of the step, then by the front wall of the object, and then by the back wall (in this case, the deep part) of the object on the second side of the step. Therefore, the arrival time (ToA) of the primary step echo differs from the arrival time of echoes generated only in the shallow or deep part, and is approximately equal to the sum of the ToA of the back wall echoes in the shallow part and the ToA of the back wall echoes in the deep part. In other words, ToA(PSE) ≈ ToA(BW 1s )+ToA(BW 1d )

[0063] As can be understood, the main step echo with the aforementioned ToA(PSE) is also the result of reflection and diffraction of ultrasonic energy other than those shown in Figure 5b. For example, Figure 5f shows that the main step echo detected by the ultrasonic probe at the same position and time as the situation shown in Figure 5b is also the result of ultrasonic energy being reflected first from the rear wall 11 of the deeper part of the object, then from the front 9, and then from the rear wall 11 of the shallower part of the object (therefore ToA ≈ ToA(BW) 1s )+ToA(BW 1d This indicates that ) becomes ). Furthermore, while the main step echo mainly consists of the aforementioned pure reflections, the main step echo (having the aforementioned ToA(PSE)) can also be the result of diffraction of ultrasonic energy. For example, Figures 5g and 5h schematically show the diffraction of ultrasonic energy by the edge of step S. As can be understood, the ToA of an echo that has experienced such diffraction is also ToA(BW 1s )+ToA(BW 1d )

[0064] As a result of these different paths, it has been found that the amplitude of the PSE is strongest when the ultrasonic probe is positioned along a step in the depth of the component. Therefore, finding the location of the peak value of the PSE can be a reliable indicator of the step's location.

[0065] As shown in Figures 5b, 5d, and 5e, multiple internal reflections within the shallow or deep parts of an object generate older generation / dependent step echoes. The arrival time of the dependent step echo is N1.ToA(BW 1s )+N2.ToA(BW 1d) becomes approximately equal to, where at least one of N1 and N2 is greater than 1. Since the amplitude of such a dependent step echo is significantly smaller than the amplitude of the primary step echo, determining the step location based on the dependent step echo is more susceptible to noise than determining the step location based on the primary step echo. Also, if the probe is directly above the step at the depth of the component, the dependent step echo may not return the maximum amplitude (as shown in Figure 5b, the path of the dependent step echo increases the x-distance between the radiating and receiving points. If the probe is directly above the step, only a relatively small number of points on the transducer can receive the dependent step echo). Therefore, in this embodiment, only the primary step echo is used to determine the step location (however, as understood, data from the dependent step echo may also be used if necessary).

[0066] As shown in Figures 7a and 7b, the amplitude of the primary step echo (labeled PSE) is significantly smaller than that of the typical / expected posterior wall echo. In Figure 7b, the PSE data is highlighted with a dashed line to aid in visualization on the graph (because the signal intensity / amplitude of the PSE data is weak, making it difficult to see).

[0067] Standard posterior wall echoes generated only in the deep parts (e.g., BW) 1d BW 2d ) and / or standard posterior wall echoes generated only in the shallow portion (e.g., BW 1s BW 2s ) From this, it is possible to estimate the position of the step. For example, as shown in Figures 7a and 7b, the data is BW 1s Signals and BW 1d This indicates that the signals overlap along the x-axis, BW 1s Signals and BW 1d The amplitude of the signal is BW 1s Signals and BW 1d By evaluating the position where the signal amplitude is substantially the same (taking into account signal loss due to the relative thickness of the portion), it is possible to estimate that this position is the location of the step.

[0068] However, the inventors discovered that even with significantly lower amplitudes in step echo measurement data (especially major step echo measurement data), it is possible to provide more accurate and reliable measurements of the step location, particularly in the case of complex parts where standard back wall echoes, generated only in shallow or deep portions, are inconsistent when approaching the step. Specifically, the inventors found that the major step echo measurement data is the largest position (i.e., the time to reach ToA(BW)). 1s )+ToA(BW 1d We discovered that by obtaining a peak signal position that is approximately equal to ( ), we can accurately and reliably indicate the depth difference of an object.

[0069] As mentioned above, the PSE data for object 10' shown in Figure 5 is difficult to see / distinguish in Figures 7a and 7b. Therefore, Figures 8a, 8b, and 8c show a more simplified embodiment, where the configuration of shallow and deep portions of object 10'' makes the PSE data in graphs 8b and 8c more clearly distinguishable from the rear wall step data generated by only the relatively shallow portion or only the relatively deep portion.

[0070] Here, with reference to Figure 9, which shows an exemplary flowchart 800 of the method according to the present invention, an exemplary method for detecting a step based on step echo measurement data is described. The method begins with step 802, which includes acquiring a set of ultrasonic echo measurement data extending across a depth step in an object. Step 802 may include an operation to measure the object in order to acquire the data. However, as can be understood, it is not necessarily required, and for example, step 802 may include an operation to receive / acquire such data (e.g., from a remote device and / or a memory device from which data has been previously acquired). As shown in Figure 6a, the set of ultrasonic echo measurement data may include data acquired by performing ultrasonic measurements (e.g., "pings") at a plurality of points P along a straight line L extending across a depth step S in an object. These measurements may be acquired with the ultrasonic probe 2 stationary at each point, or while the ultrasonic probe 2 is moving continuously. The measurement data may include data acquired using different methods / paths. For example, as shown in Figure 6b, the measurement data may include data obtained by performing ultrasonic measurements at multiple points P along a path that crosses the step S multiple times within a region A extending across the step S. As shown in Figure 6c, the measurement data may include data obtained by performing ultrasonic measurements at multiple points P along multiple laterally offset paths extending parallel to the depth step of the object, thereby covering the region A extending across the depth step of the object. As shown in Figure 6d, the measurement data may include data obtained by performing ultrasonic measurements at multiple points P at irregular (e.g., random) positions within the region A extending across the depth step of the object.

[0071] The next step 804 of process 800 involves identifying which data in the set were generated by step depths in the part (referred herein to as ultrasonic “step echo” measurement data, or simply “step echo” measurement data). An exemplary process 900 of this step is shown in Figure 10. The first step 902 of the process involves first-generation back wall echoes (BW) in the deeper portion of object 10'. 1d The time to arrival (ToA) of the object, and the first generation posterior wall echo BW in the shallow part of the object. 1s The objective is to obtain the ToA of the first-generation posterior wall echo. This may be either already known (e.g., from previous ultrasound echo measurements), estimated (e.g., from knowledge of the actual or nominal depth of the deep and shallow parts of the part), or calculated from a current set of ultrasound measurement data, for example, by measuring the ToA of the peak of the received first-generation posterior wall echo. As can be understood, if the interface features / posterior surface of the object generating the posterior wall echo are not flat and / or not parallel to the front surface, it may be advantageous to measure the ToA of the peak of the first-generation posterior wall echo received near the point (e.g., that point) where the amplitude of the first-generation posterior wall echo begins to decrease (towards the step).

[0072] The next step in the process, 904, is to obtain first-generation posterior wall echoes (BW) in the deep portion of the set of ultrasound echo measurement data. 1d ) ToA, plus first-generation posterior wall echocardiography (BW) in the shallow part 1s This involves searching for echo signal data that has a ToA that is approximately equal to the sum of the ToA of ). 1s )+ToA(BW 1d The signal data received in step )) is considered to have been generated by that step and is therefore considered to be the measurement data of the main step echo.

[0073] The method then returns to step 806 (in Figure 9), where the location of the step in the depth of the part is determined using the measurement data of the primary step echo identified in step 804. In this embodiment, the location of the measurement data of the primary step echo (identified in step 804) having the highest value / peak value is used as the location of the step. In the embodiment of Figure 6a, the determined location of the step in the depth of the part may be along a straight line L (e.g., X position data) from which the primary step echo measurement of the highest value / peak value was obtained. If necessary (and / or in embodiments where the ultrasonic probe is not attached to a coordinate positioning device), information identifying the ultrasonic measurement (e.g., "ping") from which the highest value / peak value was obtained can be output as information regarding the location of the step S. For example, referring to Figure 6a, each point P of the measurement ("ping") can be uniquely identified / tagged (e.g., numbered from 1 to #), and the information regarding the location of the step S may include only the unique identifier (e.g., number) of point P identified in step 806.

[0074] However, considering that the ultrasound device 2 is attached to the CMM200, the coordinates of the ultrasound measurement (e.g., "ping") from which the highest value / peak value was obtained can be used to determine / obtain coordinate position information regarding the depth position of the object in the step. This may be coordinate information regarding the lateral position of the object (e.g., position parallel to the front). However, by combining such lateral position information with (estimated or known) information regarding the height / depth of the relatively shallow and / or deep parts (e.g., relative to the front), three-dimensional position information regarding the position in the depth of the step can be obtained. Such information regarding the height / depth of the relatively shallow and / or deep parts can be determined from ultrasound echo measurements ("ping") using the same ultrasound probe used to obtain the ultrasound step echo measurements. In fact, such information regarding the height / depth of the relatively shallow and / or deep parts can be determined from the same set of ultrasound echo measurement data (e.g., ultrasound echo measurement data obtained at a position away from the step, as shown in Figures 5a and 5c), which may include the ultrasound step echo measurement data.

[0075] As will be explained in more detail below, positional information regarding the depth of a part can be combined with other information about the object (such as location / position / measurements).

[0076] As can be understood, the method described above in relation to the embodiment of Figure 6a can be repeated for a plurality of offset measurement lines L extending parallel to those shown in Figure 6a, thereby obtaining information about the position of the step S in both the X and Y dimensions.

[0077] As can be understood, in the embodiments of Figures 6b to 6d, step 806 may include detecting multiple points indicating the presence of a depth step in the object—for example, for each of several different Y positions, the X position / point (P) number with the highest value / peak value is detected. Thus, from the set of ultrasonic measurement data acquired using the schemes of Figures 6b, 6c, and 6d, information regarding the location of the step S in both the X and Y dimensions can be obtained. In this case as well, such information regarding the location of the step may include, for example, coordinate position data and / or, for example, a unique identifier for point P.

[0078] The information determined in step 806 can be stored and / or used independently. However, advantageously, the information regarding the location of the depth step of the part, determined in step 806, can be combined with other information about the object (known / measured or nominal / estimated). For example, “other location / measurement data about the object” can be used in combination with the information determined in step 806 to evaluate / determine the location of the depth step of the part relative to other features of the object. Thus, the method may include reading (e.g., acquiring) location / positional information about features of the object other than the step and combining such location / positional information with location / positional information about the depth step of the part. Such “other location / measurement data about the object” can be acquired by the CMM 200 collecting measurement information about the object. Such “other location / measurement data about the object” can be acquired via the ultrasound device 2 and / or via one or more other probes (e.g., contact or non-contact position measuring probes) interchangeable with the ultrasound device 2 on the quill 208 / articular head 210 of the CMM. Acquiring information about the depth of a part's step, as well as other positional / measurement data about the object, using the same CMM (Composition Machine Modeling) is particularly advantageous because it minimizes registration errors and machine-specific errors that could negatively impact the combination of information and data.

[0079] Referring to Figure 11, the inventors have confirmed that in addition to the step echo measurement data being generated by the step due to the reflection (and optionally diffraction) of ultrasonic energy as described above in relation to Figure 5 (which generated the step echo data labeled as PSE in Figures 7 and 8), ultrasonic echo measurement data can also be generated by the step edge diffracting toward the rear surface 11 of the deeper portion of object 10', which then reflects such ultrasonic energy toward the ultrasonic probe 2 (for example, as schematically shown in Figure 11). Such reflection can generate a group of "back-diffracted" step echo data (BDSE), separate from the primary step echo (PSE) data described above. The BDSE data is obtained from the set of ultrasonic echo measurement data, where ToA is 4(ToA(BW 1d ))-2(ToA(BW 1s The location can be identified by searching for echo signal data that is approximately equal to (for example, in step 804). BDSE data can be used instead of or in conjunction with PSE data to determine the location of the step. For example, the location of the step can be determined by taking the average of the locations of the peak PSE and BDSE values.

[0080] In the embodiments described above, object 10' is solid and free of defects, and the step S in the depth of the object is caused by a step in the thickness of object 10'. However, the method of the present invention is also useful for locating step in the depth of an object (measured from the front surface 9 of the object by an ultrasonic probe measuring ultrasonic echoes) caused by other factors / features. For example, Figure 12a shows a hollow object 10a, where the boundary of the hollow portion 13 causes a step S in the depth of the object (measured by an ultrasonic probe). Thus, the method of the present invention described above can be used to locate the end of a hollow portion. As also shown in Figure 12a, the rear surface 11 of object 10a does not necessarily have to be parallel to the front surface 9. This also applies to the surface of the hollow portion of an object that generates a rear wall echo of a shallow portion.

[0081] Figure 12b shows an object 10b having a constant thickness, but including an internal feature 14 made of a different material from the rest of the object 10a. Since the ultrasonic energy radiated from the ultrasonic probe is at least partially reflected at the interface between the different materials, the depth of the object measured by the ultrasonic probe performing an ultrasonic echo measurement from the front surface 9 of the object is affected by the internal feature 14. Therefore, the above-described method of the present invention can be used to determine the location of the edges of the internal feature 14.

[0082] Figure 12c shows an object having a certain thickness but possessing an internal defect 15, such as a crack. At least a portion of the ultrasonic energy radiated from the ultrasonic probe 2 is reflected by the defect 15, generating a back wall echo that is detected by the ultrasonic probe. Therefore, the depth of the object measured by the ultrasonic probe performing ultrasonic echo measurements from the front surface 9 of the object is affected by the defect 15. Thus, the method described above of the present invention can be used to pinpoint the location of the edges of the defect 15.

[0083] As described above, information regarding the depth step of an object (e.g., its position) can be combined with other information about the object. For example, referring to the embodiment in Figure 12a, it may be important for the end user to know the position of the end of the hollow portion 13 relative to the end wall of the object. Therefore, data regarding the position of the depth step obtained using the method of the present invention can be combined with known or estimated data regarding the position of the end wall. For example, such data can be estimated from a nominal model of the object (e.g., a computer-aided design (CAD) model) or obtained by measuring the object using another probe, such as a contact probe.

[0084] In the embodiments described above, the step in the depth of the object is substantially linear (in the direction perpendicular to the depth measurement, e.g., the Y direction in the figure). However, this is not necessarily required, and the step may be curved or irregularly shaped. Also, in the embodiments described above, the step in the depth of the object has a clearly defined sharp edge. However, this is not necessarily required, and for example, the edge or corner of the step may be curved.

[0085] The present invention is suitable for use with various types of ultrasound equipment, including immersion ultrasound systems. Patent documents 6, 8, and 9 describe various exemplary types of ultrasound probes in which the present invention may be used.

[0086] As can be understood, the present invention can also be used in other types of positioning devices such as robot arms and machine tool equipment, and can also be used in manually held ultrasonic inspection devices.

[0087] In the embodiment described above, ultrasonic measurement ("ping") is performed with the ultrasonic axis of the ultrasonic probe positioned perpendicular to the front surface of the object. However, this is not necessarily required.

[0088] In the embodiments described, the ultrasonic probe used to inspect an object is mounted on a device that allows the ultrasonic probe and the object being inspected to rotate / reposition relative to each other around at least one axis of rotation. However, this is not necessarily required, and the ultrasonic probe can also be mounted on a device that does not allow relative rotation of the ultrasonic probe and the object being inspected, but only relative movement.

[0089] In the embodiments described above, the location of the step in the depth of the part is determined. However, this is not necessarily required, and the method of the present invention can also be used to determine other information about the step. For example, step echo measurement data can be used to determine the sum of the thicknesses of the relatively shallow and relatively deep portions. As another example, step echo measurement data can be used to determine information about the shape of the step, for example, from the relative amplitudes of the main step echo (described later), the first generation back wall echo of the relatively shallow portion, and the first generation back wall echo of the relatively deep portion. Furthermore, the step can be compared to the nominal (or reference) data / object step by, for example, comparing the step echo measurement data of an object with the nominal step echo measurement data (or the step echo measurement data of a reference object) (e.g., to find a part that does not fit the nominal (or reference) data / object).

Claims

1. A method for determining information regarding the difference in depth of an object between a relatively shallow part and a relatively deep part of the object, measured by an ultrasonic inspection device that performs ultrasonic echo measurements from the front surface of the object, wherein the method is: A set of measurement data of ultrasonic echoes spreading across the depth step of the object is acquired, and information regarding the depth step of the object is determined using the measurement data of ultrasonic step echoes generated by the depth step of the object. Methods that include...

2. The time it takes for the measured ultrasonic step echo data to reach the ultrasonic inspection device is ToA(BW 1s ) + ToA (BW 1d The arrival time is approximately equal to the time of arrival at ToA (BW 1s ) is the time it takes for the first generation of ultrasound echoes generated by the relatively shallow portion to reach the ultrasound examination device, and ToA(BW 1d ) is the time it takes for the first generation of ultrasound echoes generated by the relatively deep portion to reach the ultrasound examination device. The method according to claim 1.

3. The measurement data of the ultrasonic step echo is the result of ultrasonic echoes received by the ultrasonic inspection device, which are reflected and / or diffracted by both the relatively shallow and relatively deep portions of the object. The method according to claim 1 or 2.

4. The measurement data of the ultrasonic step echo is the result of ultrasonic echoes received by the ultrasonic inspection device, which are first reflected by the rear wall features of one of the relatively shallow or relatively deep parts of the object, then reflected by the front surface, and then reflected by the rear wall features of the other of the relatively shallow or relatively deep parts. The method according to claim 3.

5. The peaks in the measurement data of the ultrasonic step echo are identified, and information regarding the step is determined from there. The method according to any one of claims 1 to 4.

6. The aforementioned information includes location information. The method according to any one of claims 1 to 5.

7. The position information includes information regarding the lateral position of the step, The method according to claim 6.

8. This further includes combining the information relating to the step with other information relating to the object. The method according to any one of claims 1 to 7.

9. The set of measurement data for the aforementioned ultrasound echo is acquired by an ultrasound inspection device attached to a positioning device, such as a coordinate positioning device. The method according to any one of claims 1 to 8.

10. The position information includes coordinate position information relating to the position of the step in the depth of the part. The method according to claims 6 and 9.

11. This includes combining coordinate position information relating to the depth step of the part with coordinate position information relating to at least one other feature of the object, The method according to claim 10.

12. The set of ultrasound echo measurement data includes ultrasound echo measurements acquired along a predetermined inspection line. The method according to any one of claims 1 to 11.

13. The further includes using measurement data of ultrasonic echoes acquired from the front surface to determine information regarding at least one of the thickness, material structure, or sound velocity of the object in the relatively shallow portion and / or the relatively deep portion. The method according to any one of claims 1 to 12.

14. The step of using an ultrasonic inspection device to obtain a set of measurement data of the ultrasonic echoes that spread across the depth difference of the object, The method according to any one of claims 1 to 13.

15. The ultrasound apparatus includes a single transducer that emits and detects ultrasonic energy to obtain ultrasonic echo measurements, and the method includes using a single transducer that emits and detects ultrasonic energy to obtain a set of ultrasonic echo measurement data. The method according to claim 14.

16. A method for determining information regarding the difference in depth of an object between a relatively shallow part and a relatively deep part of the object, measured by an ultrasonic inspection device that performs ultrasonic echo measurements from the front surface of the object, wherein the method is: (i) Measurement data of the ultrasonic posterior wall echo generated by the relatively shallow portion on the first side of the step, and / or (ii) Measurement data of the ultrasonic posterior wall echo generated by the relatively deep portion on the second side of the step, (iii) Measurement data of ultrasonic step echo generated by the step in depth of the object, To obtain a set of measurement data including ultrasound posterior wall echo, Within that set, the measurement data of ultrasonic step echoes generated by the depth difference of the object is identified, Using the measurement data of the identified ultrasonic step echo, information regarding the step in depth of the object is determined, Methods that include...

17. A method for determining information regarding the difference in depth of an object between a relatively shallow part and a relatively deep part of the object, measured by an ultrasonic inspection device that performs ultrasonic echo measurements from the front surface of the object, wherein the method is: This includes obtaining a set of measurement data of ultrasonic echoes that spread across the depth step of the object, and using the measurement data of ultrasonic step echoes generated by the depth step of the object to determine information about the depth step of the object, The time it takes for the measured ultrasonic step echo data to reach the ultrasonic inspection device is ToA(BW 1s ) + ToA (BW 1d The arrival time is approximately equal to the time of arrival at ToA (BW 1s ) is the time it takes for the first generation of ultrasound echoes generated by the relatively shallow portion to reach the ultrasound examination device, and ToA(BW 1d ) is the time it takes for the first generation of ultrasound echoes generated by the relatively deep portion to reach the ultrasound examination device. method.

18. A method for determining information regarding a step in depth of an object between a relatively shallow portion and a relatively deep portion of the object, measured by an ultrasonic device including a single transducer that emits and detects ultrasonic energy to perform ultrasonic echo measurements from the front surface of the object, wherein the method is: Using the single transducer, the ultrasonic energy is emitted and detected to obtain a set of measurement data of ultrasonic echoes spreading across the depth step of the object, and information regarding the depth step of the object is determined using the measurement data of ultrasonic step echoes generated by the depth step of the object. Methods that include...

19. Computer program code comprising instructions configured, when executed by a processor device, to cause the processor device to perform the method according to any one of claims 1 to 18.

20. A computer-readable medium that holds the computer program code described in claim 19.

21. An apparatus comprising at least one processor device configured to receive a set of measurement data of ultrasonic echoes spreading across a depth step of an object, and to determine information about the depth step of the object using measurement data of ultrasonic step echoes generated by the depth step of the object.

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