Amplitude filtering for phase coherent imaging

Abstract

The phase-based approach may be used for one or more of acquiring, storing, or subsequently analyzing the acquired acoustic imaging data. Such a phase-based method may include coherently summing a normalized representation or a quantized representation of A-scan data corresponding to phase information. Such methods may be referred to as "Phase Coherent Imaging" (PCI) beamforming techniques. Amplitude filtering may be applied to phase coherent imaging to, for example, weight features associated with scattering in such imaging to enhance defect contrast or suppress noise, or both.

Description

[0001] Priority Claim

[0002] This patent application claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 477,243, filed on December 27, 2022 (Attorney Docket No. 6409.233PRV) by Chi-Hang Kwan, titled "AMPLITUDE FILTERING FOR PHASE-COHERENCE IMAGING", the entire content of which is incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to, but is not limited to, non-destructive evaluation, and more particularly, to devices and techniques for providing phase-coherence imaging (PCI) based on acquired acoustic inspection data, where phase-coherence imaging can be enhanced by using amplitude filtering techniques. Background Art

[0004] Non-destructive testing (NDT) can refer to the use of one or more different techniques to inspect areas on or within an object to, for example, determine the presence of flaws or defects or otherwise characterize the object being inspected. Examples of non-destructive testing methods can include using eddy current testing methods, where electromagnetic energy is applied to the object and the induced current generated on or within the object is detected, and the value of the detected current (or associated impedance) provides an indication of the structure of the object being tested, such as indicating the presence of cracks, voids, porosity, or other non-uniformities.

[0005] Another method of NDT can include using acoustic inspection techniques, such as where one or more electro-acoustic transducers are used to acoustically penetrate areas on or within the object being tested, and the scattered or reflected acoustic energy can be detected and processed. Such scattered or reflected energy can be referred to as an acoustic echo signal. Generally, such acoustic inspection scenarios involve using acoustic frequencies within the ultrasonic frequency range, which can include, as illustrative examples, pulses having energy within a specified range, which can include values from, for example, a few hundred kilohertz to several tens of megahertz. Summary of the Invention

[0006] Acoustic tests such as ultrasound-based inspections can include focusing techniques or beamforming techniques to assist in constructing a data map or image representing an area of interest within a test sample. The use of an array of ultrasonic transducer elements can include the use of phased array beamforming methods and can be referred to as Phased Array Ultrasound Testing (PAUT). For example, delay-and-sum beamforming techniques can be used, such as delay-and-sum beamforming techniques that include the coherent summation of the time-domain representations of acoustic signals received from respective transducer elements or apertures. In another method, Total Focusing Method (TFM) beamforming techniques can be used, where one or more elements in the array (or apertures defined by such elements) are used to transmit acoustic pulses and other elements are used to receive scattered or reflected acoustic energy, and a matrix is constructed from time series (e.g., A-scans) corresponding to a sequence of transmit-receive cycles in which transmissions occur from different elements (or corresponding apertures) in the array. Such a TFM method of obtaining A-scan data for each element (or each defined aperture) in the array can be referred to as "full matrix capture" (FMC) technology.

[0007] In a manner similar to TFM imaging, phase-based methods can be used for one or more of acquisition, storage, or subsequent analysis. Such phase-based methods can include the coherent summation of normalized or quantized representations of A-scan data corresponding to phase information. Such methods can be referred to as "Phase Coherent Imaging" (PCI) beamforming techniques.

[0008] Among other things, the inventors have recognized that using phase-based imaging methods is associated with various attributes and some potential drawbacks. Phase-based imaging can be more sensitive to small omnidirectional scatterers, which can be advantageous in detecting crack tips or porosity in structures with holes. However, such sensitivity to scattering can also enhance the presence of grain echoes (e.g., in stainless steel or associated with modified grain structures in welds), which can clutter the imaging or impede the analysis of such imaging, such as by obscuring features corresponding to flaws. Among other things, the inventors have recognized that the amplitude information suppressed in phase-based imaging would otherwise show the difference between omnidirectional scatterers associated with grain noise and features of interest such as crack tips. Accordingly, the inventors have recognized that some amplitude information can be reintroduced by using amplitude data from a separate image, such as one constructed using total focusing method (TFM) beamforming. In this way, for example, a second image (or a representation thereof) constructed using TFM beamforming can be used to filter the first image corresponding to the phase-based imaging method, such as on a pixel-by-pixel or voxel-by-voxel basis. In this way, the sensitivity of the phase-based imaging method is retained, but image features associated with grain noise or other scatterers of no interest can be suppressed.

[0009] In an example, a machine-implemented method can include: obtaining acoustic echo data indicative of scattered or reflected acoustic energy corresponding to respective transmit-receive pairs of apertures, forming a first image by coherently summing representations of phase information from the acoustic echo data to establish respective first image pixel or voxel element values; forming a second image by coherently summing representations of phase information and amplitude information from the acoustic echo data to establish respective second image pixel or voxel element values; weighting the respective second image pixel or voxel element values using an amplitude filter function to establish respective weighted second image pixel or voxel element values; and adjusting the respective first image pixel or voxel element values of the first image using the respective weighted second image pixel or voxel element values from corresponding locations in the second image to establish a weighted first image.

[0010] In an example, a non-destructive testing system may perform a machine-implemented method. For example, the system may include: a test instrument that includes a transmitter circuit and a receiver circuit; at least one processor circuit communicatively coupled to the test instrument or included as part of the test instrument; and at least one memory circuit communicatively coupled to the test instrument or included as part of the test instrument, the at least one memory circuit including instructions that, when executed by the at least one processor circuit, cause the non-destructive testing system to: obtain acoustic echo data indicative of scattered or reflected acoustic energy corresponding to respective transmit-receive aperture pairs using the transmitter circuit and the receiver circuit; form a first image by coherently summing representations of phase information from the acoustic echo data to establish respective first image pixel or voxel element values; form a second image by coherently summing representations of phase information and amplitude information from the acoustic echo data to establish respective second image pixel or voxel element values; weight the respective second image pixel or voxel element values using an amplitude filter function to establish respective weighted second image pixel or voxel element values; adjust the respective first image pixel or voxel element values of the first image using the respective weighted second pixel or voxel element values from corresponding locations in the second image to establish a weighted first image; and send or present the weighted first image to a user. In any of the examples herein, the amplitude filter function may establish a non-linear mapping of input amplitude values to output amplitude values, such as having an S-shaped shape, for weighting the respective second image pixel or voxel element values. For example, a hyperbolic tangent function may be used as the amplitude filter function. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In the drawings, which are not necessarily to scale, like reference numerals may describe similar components in different views. Like reference numerals with different letter suffixes may represent different instances of similar components. The drawings generally illustrate, by way of example and not limitation, the various embodiments discussed herein.

[0012] Figure 1 Generally illustrated is an example including an acoustic inspection system that may be used to perform at least a portion of one or more of the techniques shown and described herein.

[0013] Figure 2 Generally illustrated is a technique, such as a machine-implemented method, that may include a phase-based acoustic beamforming method for acoustic imaging, weighted using amplitude information from another beamforming method.

[0014] Figure 3A Generally illustrated is an illustrative example of an image constructed using total focusing method (TFM) beamforming technology.

[0015] Figure 3B Illustrative examples of images constructed using phase-based beamforming techniques are generally shown.

[0016] Figure 3C Illustrative examples of weighted TFM images to which an amplitude filter has been applied are generally shown.

[0017] Figure 4A Illustrative examples of functions that can be used to implement amplitude filtering of images constructed using phase-based acoustic beamforming are generally shown, where the filter function can include a scaling factor.

[0018] Figure 4B Illustrative examples of techniques that include scaling factors used in amplitude filter functions for parameterization Figure 4A are generally shown.

[0019] Figure 4C Illustrative examples of other classes of sigmoid functions that can be used to implement amplitude filtering are generally shown.

[0020] Figure 5A , Figure 5C and Figure 5E Illustrative examples of images constructed using phase-based beamforming techniques without amplitude-based filtering are shown.

[0021] Figure 5B , Figure 5D and Figure 5F Illustrative examples of images constructed using phase-based beamforming techniques are shown, where the images are weighted using amplitude information from another beamforming method to provide amplitude-based filtering.

[0022] Figure 6 A block diagram of an example of a machine 600 that can execute any one or more of the techniques (e.g., methods) discussed herein is shown. Detailed Description

[0023] As mentioned above, acoustic inspection can include the use of total focusing method (TFM) beamforming techniques, where one or more elements in the array (or an aperture defined by such elements) are used to transmit acoustic pulses, and other elements are used to receive scattered or reflected acoustic energy, and a matrix is constructed represented by a time series corresponding to a sequence of transmit-receive cycles (e.g., A-scans), in which transmissions occur from different elements (or corresponding apertures) in the array. In a manner similar to TFM imaging, phase-based methods can be used for one or more of acquisition, storage, or subsequent analysis. Such phase-based methods can include coherent summation of a normalized or quantized representation of A-scan data corresponding to phase information. Such a method can be referred to as “phase coherent imaging” (PCI) beamforming technique.

[0024] As discussed above, phase-based methods such as phase coherent imaging (PCI) can provide enhanced sensitivity to small omnidirectional scatterers such as crack tips and perforated structures by normalizing and factoring out the amplitude contributions of the received signals prior to coherent summation. The present subject matter can be used to filter noise such as grain noise in a PCI image using information from corresponding amplitude- and phase-based imaging methods such as TFM images (e.g., images constructed using TFM beamforming). By way of illustration, PCI images and TFM images can be constructed based on the acquired acoustic echo data corresponding to respective transmit-receive aperture pairs. A TFM image is weighted using an amplitude filter function that non-linearly adjusts the amplitude values (e.g., the envelope amplitude values corresponding to respective pixels or voxels).

[0025] The weighted TFM image can be used to adjust the values (e.g., pixel or voxel values) of the corresponding PCI image to obtain an enhanced image (e.g., with reduced grain noise or emphasizing scatterers of interest such as crack tips or perforated structures). Generally, the amplitude filter function applied to the TFM image typically corresponds to a sigmoidal non-linear mapping of the amplitude values. The argument of the filter function can be a normalized or scaled representation of the TFM image pixel or voxel values. This enables suppression of grain noise and other lower amplitude features in the weighted TFM image prior to adjusting the PCI image using the weighted TFM image. The resulting weighted PCI image retains the enhanced sensitivity of PCI while reducing noise such as grain noise.

[0026] Figure 1Generally shown is an example including an acoustic inspection system 100, which can be used, for example, to perform at least a portion of one or more of the techniques shown and described herein. The inspection system 100 can include a test instrument 140 such as a hand-held or portable component. The test instrument 140 can be electrically coupled to a probe assembly 150 using, for example, a multi-conductor interconnect 130. The probe assembly 150 can include one or more electroacoustic transducers, such as a transducer array 152 including respective transducers 154A through 154N. The transducer array can follow a linear or curved profile, or can include an array of elements extending along two axes to provide, for example, a matrix of transducer elements. The footprint of the elements need not be square or need not be arranged along a straight axis. Element size and spacing can vary according to the inspection application.

[0027] A modular probe assembly 150 configuration can be used to enable, for example, the test instrument 140 to be used with a variety of different probe assemblies. Generally, the transducer array 152 includes piezoelectric transducers that can be acoustically coupled to a target 158 (e.g., a test specimen or “object under test”) through, for example, a coupling medium 156. The coupling medium can include a fluid or gel or solid film (e.g., an elastomer or other polymeric material), or a combination of a fluid, gel, or solid structure. For example, the acoustic transducer assembly can include a transducer array coupled to a wedge structure that includes a rigid thermoset polymer (e.g., available from C-Lec Plastics) having known acoustic propagation characteristics, and during testing, water can be injected as the coupling medium 156 between the wedge and the structure under test, or the test can be performed by otherwise immersing the coupling medium at the interface between the probe assembly 150 and the target 158. ) and during testing, water can be injected as the coupling medium 156 between the wedge and the structure under test, or the test can be performed by otherwise immersing the coupling medium at the interface between the probe assembly 150 and the target 158.

[0028] The test instrument 140 can include digital and analog circuitry, such as a front-end circuit 122 including one or more transmit signal chains, receive signal chains, or switching circuitry (e.g., transmit / receive switching circuitry). The transmit signal chain can include amplifier and filter circuitry to provide, for example, transmit pulses for delivery through the interconnect 130 to the probe assembly 150 for acoustic transmission through the target 158 to image or otherwise detect a defect 160 in or on the target 158 structure by receiving scattered or reflected acoustic energy in response to the acoustic transmission.

[0029] Although Figure 1A single probe assembly 150 and a single transducer array 152 are shown, but other configurations may also be used, such as multiple probe assemblies connected to a single test instrument 140 or multiple transducer arrays 152 used with a single probe assembly 150 or multiple probe assemblies, for a pitch / catch inspection mode. Similarly, coordination between multiple test instruments 140 may be used to perform test protocols, such as in response to an overall test scenario established according to the main test instrument 140 or established by another remote system (e.g., computing facility 108 or a general computing device such as a laptop computer 132, a tablet computer, a smart phone, a desktop computer, etc.). As an illustrative example, the test scenario may be established according to a published standard or regulatory requirement and may be executed at initial formulation or repeated for continuous monitoring.

[0030] The receive signal chain of the front-end circuit 122 may include one or more filter or amplifier circuits and an analog-to-digital conversion facility to, for example, digitize echo signals received using the probe assembly 150. The digitization may be performed coherently to, for example, provide multiple digitized data channels that are aligned with or referenced to each other in time or phase. The front-end circuit may be coupled to and controlled by one or more processor circuits, such as the processor circuit 102 included as part of the test instrument 140. The processor circuit may be coupled to a memory circuit 104 to, for example, execute instructions for causing the test instrument 140 to perform one or more of acoustic wave transmission, acoustic wave acquisition, processing, or storage of data related to acoustic inspection or otherwise perform the techniques shown and described herein. The test instrument 140 may be communicatively coupled to other parts of the system 100, such as using a wired or wireless communication interface 120.

[0031] For example, execution of one or more of the techniques shown and described herein can be implemented on the onboard test instrument 140 or using other processing or storage facilities (e.g., using computing facility 108 or a general-purpose computing device such as a laptop computer 132, a tablet computer, a smartphone, a desktop computer, etc.). For example, processing tasks that would be undesirably slow or exceed the capabilities of the test instrument 140 if performed on the onboard test instrument 140 can be performed remotely (e.g., on a separate system), such as in response to a request from the test instrument 140. Similarly, storage of imaging data or intermediate data such as an A-scan matrix of time-series data or other representations of such data can be implemented, for example, using a remote facility communicatively coupled to the test instrument 140. The test instrument can include a display 110 for, for example, presenting configuration information or results, and an input device 112 for receiving operator commands, configuration information, or responses to queries, including, for example, one or more of a keyboard, a trackball, function keys or soft keys, a mouse interface, a touch screen, a stylus, etc.

[0032] Figure 2 Generally, a technique 200 is shown, such as a machine-implemented method, which may include a phase-based acoustic beamforming method for acoustic imaging that uses amplitude information from another beamforming method for weighting. For example, at 205, acoustic echo data may be acquired. Such acoustic echo data may include a time-series resolved signal representation that may be processed to extract amplitude and phase terms.

[0033] At 210, corresponding pixel values can be determined by forming a first image including a coherent summation of a representation of phase information (e.g., quantized time series data indicating phase whose amplitude has been normalized) to form a first image. Such an approach can be similar to delay-and-sum beamforming, but where the amplitude information is normalized. As an illustration, analytical notation shows a coherent summation corresponding to TFM beamforming (shown below in Equation 1), where TFM(x) can be used to establish a pixel or voxel value for a spatial location described by a vector x, and s tr represents the complex-valued analytical signal response for the corresponding transmit-receive pair at element indices t and r:

[0034] TFM(x)=∑ t ∑ r |s tr (x)|exp(i∠s tr (x)) (Equation 1)

[0035] In a phase-based method, the amplitude terms can be factored out of the summation process, leaving the phase-related coherent terms to be summed (“exp(i∠s tr (x))”):

[0036] PCI(x) = ∑ t ∑ r exp(i∠s tr (x)) (Equation 2)

[0037] By using such factorization, factors affecting the amplitude are suppressed (since such factors may affect terms that have now been “moved out” of the summation), while the phase-related terms (e.g., terms associated with scatterers or other features of interest) remain unchanged. A method similar to TFM beamforming can be used to construct an image, but using the normalized amplitude values for each transmit-receive pair (t,r) and performing the summation in a manner similar to that shown in Equation 2. Such a method for forming the first image at 210 can be referred to as phase coherent imaging (PCI). In an example of how PCI is implemented, the binary representation of the phase-related coherent terms still enables coherent summation and can reduce one or more of the computational complexity or the data storage burden. The use of such binarization can be represented by the following summation process:

[0038]

[0039] In Equation 3, the following binarization method is used:

[0040]

[0041] As an illustration, Figure 3B Overall, an image constructed using such phase-based beamforming techniques is shown. Compared to TFM beamforming, the PCI method can be more sensitive to small omnidirectional scatterers such as crack tips and perforated structures, where TFM beamforming uses both amplitude and phase information in coherent summation. In PCI, compared to TFM imaging, the back wall and other specular reflections are generally not as strong or saturated, and using PCI can facilitate multimode imaging because, through normalization, the corresponding propagation modes will have similar amplitude scaling.

[0042] As discussed elsewhere in this document, the PCI method may have drawbacks such as enhanced grain echoes or other features that do not correspond to the flaw of interest. To help attenuate such noise, a filtering process can be used. Return reference Figure 2, at 215, a second image can be formed by coherently summing the representations of the phase information and the amplitude information. For example, at 215, a TFM beamforming method can be used to generate the second image. [[ID= An illustrative example of such an image constructed using total focusing method (TFM) beamforming techniques is generally shown.

[0043] At ​ , at 220, a second image (e.g., formed using TFM imaging including amplitude and phase information) can be weighted using an amplitude filter function. Generally, the weighting can include an S-shaped function. For example, hyperbolic tangent can be applied on a pixel-by-pixel or voxel-by-voxel basis to the envelope TFM image. Various examples of the amplitude filter function are discussed below with respect to ​ , ​ and ​ . ​ An illustrative example of a weighted TFM image to which an amplitude filter (such as provided at 225 as shown in ​ ) has been applied is generally shown. At ​ , at 225, the weighted second image can be used to adjust the first image, such as by multiplying the pixel values in the first image (e.g., constructed using phase-based imaging) by the weighted second image established at 220 (e.g., constructed using TFM and weighted using an amplitude filter). This can be referred to as an amplitude-filtered PCI image. At 230, the image (or other image or data) established at 225 can be stored, transmitted, or presented. For example, the amplitude-filtered PCI image can be presented to a user on a display of an acquisition instrument, or presented using another device such as a tablet computer, a laptop computer, a mobile device, or more generally other clients (e.g., web-based clients or other clients such as coupled to additional processing facilities or cloud facilities).

[0044] As discussed further below, various functions can be used to establish the amplitude filter function, such as including a scaling factor in the argument of such a function or even parameterizing the scaling factor. Optionally, technique 200 can include establishing parameters of the amplitude filter function at 240. For example, as an illustrative example, such parameters can include a scaling factor value, a parameter for establishing such a scaling factor, or a choice of filter shape or function.

[0045] ​ An illustrative example of a function that can be used to implement amplitude filtering of an image constructed using phase-based acoustic beamforming is generally shown, where the amplitude filter function can include a scaling factor. As mentioned above, the amplitude filter function can be S-shaped, and ​An illustrative example of an amplitude filter function including a hyperbolic tangent is shown, which can be applied to an envelope TFM image on a pixel-by-pixel or voxel-by-voxel basis. For example, as shown in the following analytical expression, max|TFM| represents the scalar value of the maximum envelope amplitude in the TFM image, and |TFM(x)| represents the envelope amplitude at the corresponding pixel or voxel position, and the argument of the hyperbolic tangent can be the ratio of |TFM(x)| to max|TFM|:

[0046]

[0047] The expression for the amplitude-filtered PCI image is shown below, where PCI filt (x) represents the pixel or voxel value at position x in the amplitude-filtered image, and PCI(x) represents the corresponding pixel or voxel value in the unfiltered PCI image, multiplied by the corresponding weighted TFM image pixel or voxel value:

[0048]

[0049] Generally, the hyperbolic tangent function can be represented by the following expression:

[0050]

[0051] The hyperbolic tangent function has the following properties: it is nearly linear for small z values (e.g., |z| < 0.5) and saturated for large z values (e.g., |z| > 2.0). Therefore, an amplitude filter function based on the hyperbolic tangent function can be used to filter out echoes with very small amplitudes (e.g., grain noise) without attenuating the medium (e.g., crack tip) or large-amplitude features (e.g., back wall reflection) in the TFM image. Using the ratio scales the TFM image pixel or voxel values to 0 to 1. In the example of Equation 5 above, c can represent a scaling factor that can be defined as shown in ​ and ​ shows an illustrative example of a technique including a scaling factor used in an amplitude filter function for parameterizing ​ . The amount of filtering of low-amplitude values (such as those associated with grain noise) can be controlled by the scaling factor value.

[0052] As an illustration, in the limit where c approaches zero, the hyperbolic tangent function is nearly linear, and the expression approaches:

[0053]

[0054] In the example where c is close to zero, the above expression represents the scaled product of PCI and the amplitude TFM. In contrast, in the limit where c is very large, the expression is close to PCI filt (r) = PCI(r), corresponding to the unfiltered PCI image. Without being bound by theory, a value of "c" of about 8 is an intermediate value for the following ​ The test cases shown in the following figures appear to work well. The scaling factor c itself can be parameterized by another variable, such as denoted by s, to linearize the scaling response. An illustrative example of such a parameterization can be expressed as follows:

[0055] c(s)=10 2.3s -0.5 (Equation 9)

[0056] ​ The general description includes illustrative examples of other sigmoid functions that can be used to implement amplitude filtering. ​ tanh(x) is not the only sigmoid-like function that can be used as a magnitude filter function. Simpler algebraic expressions can be used to speed up the calculations of the operations involved in applying the magnitude filter. ​ Examples shown in include the hyperbolic tangent, the error function (erf), the inverse tangent function, the Goodman function (gd), and the expressions x / (1+|x|) and x / (sqrt(1+x 2 )). If a linear region close to zero (corresponding to the dashed line) is deemed unnecessary, other functions that smoothly transition from zero (e.g., defining the filter region) to a constant value (e.g., a saturation region) can be used. This can include piecewise amplitude filter functions or other shapes.

[0057] ​ 、 ​ and ​ An illustrative example of an image constructed using phase-based beamforming techniques without amplitude-based filtering is shown. ​ 、 ​ and ​ were obtained at different physical locations along the sample and show indications of stress corrosion cracking. The acoustic inspection data were acquired using a 10DL64-Rex1-HC-PR probe and wedge combination (available from Evident Scientific). ​ 、 ​ and ​ In each of the images, in addition to features corresponding to stress corrosion cracking, grain noise or other scatterers appear in the image.

[0058] ​ 、 ​ and​ An illustrative example of an image constructed using phase-based beamforming techniques is shown, where the image is weighted using amplitude information from an additional beamforming method to provide amplitude-based filtering. In ​ 、 ​ and ​ , a c value of 8 is used in each, and ​ 、 ​ and ​ , the grain noise has been reduced while still retaining most (but not necessarily all) of the features indicative of stress corrosion cracking. In this way, the signal-to-noise ratio has been enhanced while still maintaining the enhanced sensitivity associated with PCI imaging.

[0059] Generally, the methods described herein include establishing a first image using a phase-based method (e.g., PCI), and establishing a second image using an amplitude- and phase-based method (e.g., TFM beamforming), then applying an amplitude filter to the second image, and using the weighted second image to adjust the first image. Such methods involve two separate coherent summation operations corresponding to each respective image. However, other implementations are possible. For example, amplitude filtering can be performed on the amplitude terms in the coherent summation to obtain an equivalent result, where only a single image is constructed based on the coherent summation. In this method, as illustratively shown in the following expression, the amplitude filter is embedded in the coherent summation:

[0060] TFM filt (x)=∑ t ∑ r tanh(c|s tr (x)|)exp(i∠s tr (x)) (Equation 10)

[0061] Similar to the example described above, the method of Equation 10 can include a scaling factor c. The value of c can be difficult to determine a priori because different inspection configurations (or inspection modes) typically involve different c values. Thus, unlike methods that perform amplitude filtering by applying a filter to the image data after summation, as illustratively shown in ​ , the method of Equation 10 can eliminate the adjustment after summation. The method of Equation 10 is also generally more computationally intensive than other methods.

[0062] ​FIG. shows a block diagram of an example of a machine 600 that can perform any one or more of the techniques (e.g., methods) discussed herein. The machine 600 (e.g., a computer system) can include a hardware processor 602 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory 604, and a static memory 606 connected via an interconnection 630 (e.g., a link or a bus), as some or all of these components can constitute the hardware for the systems or related implementations discussed above.

[0063] Specific examples of the main memory 604 include random access memory (RAM) and semiconductor memory devices that can include storage locations in a semiconductor such as registers. Specific examples of the static memory 606 include: non-volatile memories such as semiconductor storage devices (e.g., electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)) and flash memory devices; magnetic disks such as internal hard disks and removable disks; magneto-optical disks; RAM; or optical media such as CD-ROM and DVD-ROM disks.

[0064] The machine 600 can also include a display device 610, an input device 612 (e.g., a keyboard), and a user interface (UI) navigation device 614 (e.g., a mouse). In an example, the display device 610, the input device 612, and the UI navigation device 614 can be a touch screen display. The machine 600 can include a mass storage device 608 (e.g., a drive unit), a signal generation device 618 (e.g., a speaker), a network interface device 620, and one or more sensors 616, such as a global positioning system (GPS) sensor, a compass, an accelerometer, or some other sensor. The machine 600 can include an output controller 628, such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate with or control one or more peripheral devices (e.g., a printer, a card reader, etc.).

[0065] The mass storage device 608 may include a machine-readable medium 622 on which a set or more sets of data structures or instructions 624 (e.g., software) are stored, and the data structures or instructions 624 implement or are utilized by any one or more of the techniques or functions described herein. During execution of the instructions 624 by the machine 600, the instructions 624 may also reside completely or at least partially within the main memory 604, within the static memory 606, or within the hardware processor 602. In an example, one or any combination of the hardware processor 602, the main memory 604, the static memory 606, or the mass storage device 608 includes the machine-readable medium.

[0066] Specific examples of the machine-readable medium include one or more of the following: non-volatile memory such as semiconductor storage devices (e.g., EPROM or EEPROM) and flash memory devices; magnetic disks such as internal hard disks and removable disks; magneto-optical disks; RAM; or optical media such as CD-ROM and DVD-ROM disks. Although the machine-readable medium is shown as a single medium, the term "machine-readable medium" may include a single medium or multiple media (e.g., a centralized or distributed database, or associated caches and servers) configured to store one or more instructions 624.

[0067] The devices of the machine 600 include one or more of the following: a hardware processor 602 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), the main memory 604 and the static memory 606, sensors 616, a network interface device 620, an antenna, a display device 610, an input device 612, a UI navigation device 614, a mass storage device 608, instructions 624, a signal generation device 618, or an output controller 628. The device may be configured to perform one or more of the methods or operations disclosed herein.

[0068] The term "machine-readable medium" includes, for example, any medium that can store, encode, or carry instructions that are executed by machine 600 and cause machine 600 to perform any one or more of the techniques in the technology of the present disclosure, or cause another device or system to perform any one or more of the techniques, or any medium that can store, encrypt, or carry data structures used by such instructions or associated with such instructions. Non-limiting examples of machine-readable media include solid-state memory, optical media, or magnetic media. Specific examples of machine-readable media include: non-volatile memory, such as semiconductor storage devices (e.g., electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)), and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; random access memory (RAM); or optical media, such as CD-ROM and DVD-ROM disks. In some examples, the machine-readable medium includes a non-transitory machine-readable medium. In some examples, the machine-readable medium includes a machine-readable medium that is not a transitory propagated signal.

[0069] Instructions 624 can be sent or received via a communication network 626 using a transmission medium through a network interface device 620, for example, using any one of several transmission protocols (e.g., Frame Relay, Internet Protocol (IP), Transmission Control Protocol (TCP), User Datagram Protocol (UDP), Hypertext Transfer Protocol (HTTP), etc.). Example communication networks include local area networks (LANs), wide area networks (WANs), packet data networks (e.g., the Internet), mobile phone networks (e.g., cellular networks), plain old telephone (POTS) networks, and wireless data networks (e.g., the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard family, known as Wi-Fi), the IEEE 802.15.4 standard family, the Long Term Evolution (LTE) 4G or 5G standard family, the Universal Mobile Telecommunications System (UMTS) standard family, peer-to-peer (P2P) networks, satellite communication networks, etc.

[0070] In an example, the network interface device 620 includes one or more physical jacks (e.g., Ethernet jacks, coaxial jacks, or other interconnect jacks) for accessing the communication network 626 or one or more antennas. In an example, the network interface device 620 includes one or more antennas to perform wireless communication using at least one of single-input multiple-output (SIMO), multiple-input multiple-output (MIMO), or multiple-input single-output (MISO) techniques. In some examples, the network interface device 620 uses multi-user MIMO techniques to perform wireless communication. The term "transmission medium" should be regarded as including any intangible medium that can store, encode, or carry instructions for execution by machine 600, and the term "transmission medium" includes digital communication signals or analog communication signals or other intangible media to facilitate the communication of such software.

[0071] ​

[0072] Each of the above non-limiting aspects can exist independently, or can be combined with one or more of the other aspects or other topics described herein in various arrangements or combinations.

[0073] The detailed description above includes references to the accompanying drawings, which form a part of the detailed description. The drawings illustrate, by way of example, specific embodiments in which the invention may be practiced. Such embodiments are also commonly referred to as "examples". Such examples may include elements other than those shown or described. However, the inventors also contemplate examples in which only those elements shown or described are provided. In addition, the inventors also contemplate examples using any combination or arrangement of those elements (or one or more aspects of those elements) shown or described with respect to a particular example (or one or more aspects of a particular example) or with respect to other examples (or one or more aspects of other examples) shown or described herein.

[0074] In the case of any inconsistency in usage between this document and any document incorporated by reference, the usage in this document shall prevail.

[0075] In this document, as is common in patent documents, the term "a" or "an" is used to include one or more than one, regardless of any other instances or uses of "at least one" or "one or more". In this document, unless otherwise indicated, the term "or" is used to mean non-exclusive or, such that "A or B" includes "A but not B", "B but not A", and "A and B". In this document, the terms "comprising" and "in" are used as the plain English equivalents of the corresponding terms "including" and "wherein". Additionally, in the appended claims, the terms "comprising" and "including" are open-ended, that is, a system, apparatus, article, composition, formulation, or process that includes elements other than those listed after such terms in the claims is still considered to fall within the scope of that claim. Further, in the appended claims, the terms "first", "second", and "third", etc. are used only as labels and are not intended to impose numerical requirements on their objects.

[0076] The method examples described herein can be at least partially implemented by a machine or a computer. Some examples can include a computer-readable medium or a machine-readable medium encoded with instructions operable to configure an electronic device to perform the methods described in the examples above. The implementation of such methods can include code, such as microcode, assembly language code, higher-level language code, etc. Such code can include computer-readable instructions for performing various methods. The code can form part of a computer program product. For example, such instructions can be read and executed by one or more processors to enable the performance of operations including the methods. The instructions are in any suitable form, such as but not limited to source code, compiled code, interpreted code, executable code, static code, dynamic code, etc. In addition, in the examples, such as during execution or at other times, the code can be tangibly stored on one or more volatile, non-transitory or non-volatile tangible computer-readable media. Examples of such tangible computer-readable media can include but are not limited to hard disks, removable disks, removable optical disks (e.g., compact disks and digital video disks), magnetic tape cartridges, memory cards or memory sticks, random access memory (RAM), read-only memory (ROM), etc.

[0077] The above description is intended to be illustrative and not restrictive. For example, the above examples (or one or more aspects thereof) can be used in combination with each other. For example, those of ordinary skill in the art can use other embodiments after reviewing the above description. The abstract is provided to enable the reader to quickly ascertain the nature of the technical disclosure. The abstract is submitted on the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the above detailed description, various features can be combined together to simplify the disclosure. This should not be construed to mean that the disclosed features not claimed are necessary for any claim. Rather, the subject matter of the invention can lie in less than all of the features of a particular disclosed embodiment. Thus, the appended claims are hereby incorporated as examples or embodiments into the detailed description, where each claim stands on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the present invention should be determined with reference to the appended claims and the full scope of equivalents to which such claims are entitled.

Claims

1. A machine-implemented method, comprising: obtaining acoustic echo data indicative of scattered or reflected acoustic energy corresponding to a respective transmit-receive aperture pair; forming a first image by coherently summing representations of phase information from the acoustic echo data to establish respective first image pixel or voxel element values; forming a second image by coherently summing representations of the phase information and amplitude information from the acoustic echo data to establish respective second image pixel or voxel element values; weighting the respective second image pixel or voxel element values using an amplitude filter function to establish respective weighted second image pixel or voxel element values; and adjusting respective first image pixel or voxel element values of the first image using the respective weighted second image pixel or voxel element values from corresponding locations in the second image to establish a weighted first image.

2. The machine-implemented method according to claim 1, Among them, wherein forming the first image by coherently summing representations of the phase information includes normalizing the amplitude of the received acoustic echo data formed from the received portion of the respective transmit-receive aperture pair prior to the coherent summation.

3. The machine-implemented method according to any one of claims 1 or 2, wherein, The amplitude filter function includes a sigmoid function having a non-linear mapping of input amplitude values to output amplitude values for weighting the respective second image pixel or voxel element values.

4. The machine-implemented method according to any one of claims 1 or 2, wherein, The amplitude filter function includes a hyperbolic tangent function.

5. The machine-implemented method according to any one of claims 1 to 4, wherein, The argument of the amplitude filter function includes a normalized representation of the respective second image pixel or voxel value.

6. The machine-implemented method according to claim 5, wherein, Scaling the argument of the amplitude filter function using a scaling factor.

7. The machine-implemented method according to claim 6, comprising: Adjusting the scaling factor in response to user input.

8. The machine-implemented method according to any one of claims 6 or 7, wherein, The scaling factor is parameterized.

9. The machine-implemented method according to any one of claims 1 to 8, wherein, Obtaining acoustic echo data indicative of scattered or reflected acoustic energy corresponding to a respective transmit-receive aperture pair includes performing full matrix capture (FMC) acquisition.

10. The machine-implemented method according to claim 9, wherein, Forming the first image including coherently summing the representations includes phase coherent imaging (PCI) technique; and wherein forming the second image including coherently summing the representations includes total focusing method (TFM) technique.

11. The machine-implemented method according to any one of claims 1 to 10, wherein, Adjusting respective first image pixel or voxel element values of the first image using the respective weighted second image pixel or voxel element values from corresponding locations in the second image includes scaling the pixel or voxel element amplitude values of the first image using the pixel or voxel element amplitude values from corresponding locations in the second image.

12. The machine-implemented method according to claim 11, wherein, The respective pixel or voxel element values of the first image correspond to one of: the maximum amplitude of the complex-valued time series representation of the coherent summation representation of the phase information from the acoustic echo data, or the maximum amplitude of the real part of the complex-valued time series representation of the coherent summation representation of the phase information.

13. The machine-implemented method according to any one of claims 1 to 12, comprising: Presenting the weighted first image to a user via a display.

14. A non-destructive testing system, comprising: a testing instrument including a transmitter circuit and a receiver circuit; At least one processor circuit communicatively coupled to the test instrument or included as part of the test instrument; and At least one memory circuit communicatively coupled to the test instrument or included as part of the test instrument, the at least one memory circuit including instructions that, when executed by the at least one processor circuit, cause the non-destructive testing system to: Use the transmitter circuit and the receiver circuit to acquire acoustic echo data indicative of scattered or reflected acoustic energy corresponding to respective transmit-receive aperture pairs; Form a first image by coherently summing representations of phase information from the acoustic echo data to establish respective first image pixel or voxel element values; Form a second image by coherently summing representations of the phase information and amplitude information from the acoustic echo data to establish respective second image pixel or voxel element values; Weight the respective second image pixel or voxel element values using an amplitude filter function to establish respective weighted second image pixel or voxel element values; Adjust respective first image pixel or voxel element values of the first image using the respective weighted second image pixel or voxel element values from corresponding locations in the second image to establish a weighted first image; and Transmit or present the weighted first image to a user.

15. The non-destructive testing system according to claim 14, wherein, The at least one processor circuit and the at least one memory circuit are included as part of the test instrument; and wherein the non-destructive testing system includes a test probe assembly including an electroacoustic transducer array, the transmitter circuit and the receiver circuit communicatively coupled to the electroacoustic transducer array to generate acoustic emission pulses and receive scattered or reflected acoustic energy in response to the generated acoustic emission pulses.

16. The non-destructive testing system according to any one of claims 14 or 15, including a display configured to present the weighted first image.

17. The non-destructive testing system according to any one of claims 14 to 16, wherein, The amplitude filter function includes an S-shaped function having a non-linear mapping from an input amplitude value to an output amplitude value for weighting respective second image pixel or voxel element values.

18. The non-destructive testing system according to any one of claims 14 to 17, wherein, The argument of the amplitude filter function includes: a normalized representation of respective second image pixel or voxel values scaled using a configurable scaling factor.

19. The non-destructive testing system according to claim 18, wherein, The configurable scaling factor is parameterized.

20. A non-destructive inspection system, comprising: Means for acquiring acoustic echo data indicative of scattered or reflected acoustic energy corresponding to respective transmit-receive aperture pairs, the acoustic echo data including a time series corresponding to respective transmit-receive aperture pairs; Means for forming a first image using phase coherent imaging techniques by establishing respective first image pixel or voxel element values using phase information from the acoustic echo data; Means for forming a second image using full focus method imaging techniques by establishing respective second image pixel or voxel element values using the phase information and amplitude information from the acoustic echo data; and Apparatus for adjusting corresponding first image pixel or voxel element values of a first image using corresponding weighted second image pixel or voxel element values from corresponding locations in the second image to establish a weighted first image, wherein a magnitude filter function applied to the second image is used to establish the corresponding weighted second image pixel or voxel element values.

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