Phase-based method for ultrasound examination

Abstract

Phase-based methods can be used for one or more of acquisition, storage, or subsequent analysis (e.g., A-scan reconstruction or full focus method imaging) to support acoustic inspection. For example, binarization or other quantization techniques can be used to compress the amount of data associated with time series signal acquisition. A representation of phase information from the time series signals can be generated, e.g., by processing the binarized time series signals or otherwise quantized time series signals. As an illustrative example, using the representation of phase information, one or more A-scan reconstructions can be performed using phase summing techniques, e.g., for pulse echo A-scan inspection, or TFM imaging techniques can be used. In such phase summing methods, the time series representations of phase data can be summed, e.g., where each time series can be delayed (or phase-rotated) by an appropriate delay value, and then aggregated.

Description

[0001] Claiming priority

[0002] This patent application claims the priority of each of the following: (1) U.S. Provisional Patent Application Serial No. 62 / 983,172 entitled “PHASE-BASED APPROACH FOR ULTRASONIC INSPECTION” filed on February 28, 2020 (Attorney’s File No. 6409.011PRV); and (2) U.S. Provisional Patent Application Serial No. 63 / 087,521 entitled “PHASE-BASED APPROACH FOR ULTRASONIC INSPECTION” filed on October 5, 2020 (Attorney’s File No. 6409.011PV2), each of which is incorporated herein by reference in its entirety. Technical Field

[0003] This document generally relates to, but is not limited to, non-destructive assessment, and more specifically to apparatus and techniques for performing ultrasound examinations using acquired phase data. Background Technology

[0004] Various inspection techniques can be used to image or otherwise analyze structures without damaging them. For example, one or more of X-ray inspection, eddy current inspection, or acoustic (e.g., ultrasound) inspection can be used to obtain data for imaging features on or within a test sample. For example, an array of ultrasonic transducer elements can be used to perform acoustic imaging, such as imaging a region of interest within a test sample. Summary of the Invention

[0005] Acoustic testing such as ultrasound-based inspection can include focused or beamforming techniques to help construct data maps or images representative of regions 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 ultrasonic testing (PAUT). For example, a delay-and-sum beamforming technique can be used, for example including the coherent summation of time-domain representations of acoustic signals received from respective transducer elements or apertures. In another approach, a total focusing method (TFM) technique can be used in which one or more elements in the array (or an aperture defined by such elements) are used to transmit an acoustic pulse while other elements are used to receive scattered or reflected acoustic energy, and a matrix of time series (e.g., A-scans) representations corresponding to a sequence of transmit-receive cycles is constructed, with the transmission occurring from different elements (or corresponding apertures) in the array. Such a TFM approach to obtaining A-scan data for each element (or each defined aperture) in the array can be referred to as a“full matrix capture” (FMC) technique.

[0006] The present inventors have recognized, among other things, that capturing time series A-scan data for PAUT or TFM applications can involve generating a substantial amount of data. For example, A-scan time series data can be obtained through analog-to-digital conversion, for example having a corresponding amplitude resolution (e.g., 8-bit or 12-bit resolution) and a time resolution (e.g., corresponding to a sampling rate exceeding tens or hundreds of megasamples per second). Such“full” amplitude resolution and time resolution can result in gigabit time series data for each received A-scan recording for later processing as a full bandwidth resolution and full resolution representation of such signals. Such a large amount of data can be cumbersome to transfer between devices or to store. Among other things, such a large amount of data can practically limit the number of transducer elements or aperture elements used to perform acoustic testing. To address such technical challenges, the present inventors have recognized, among other things, that phase-based approaches can be used for one or more of acquisition, storage, or subsequent analysis (e.g., A-scan reconstruction or TFM imaging) to support acoustic inspection. For example, the present subject matter can include the use of binarization or other quantization techniques to compress the amount of data associated with time series signal (e.g., A-scan) acquisition. A representation of phase information from a time series signal can be generated, for example by processing a binarized time series signal or otherwise quantized time series signal.

[0007] For example, the transient data indicative of edge transitions within the binarized data can be one or more data stored or transmitted for later use to construct a time-domain representation of an instantaneous phase signal corresponding to the instantaneous phase of the original time series A-scan signal. Such transient data indicative of edge transitions can represent a compressed (e.g., less data volume) representation of the acquired time series data as compared to a full analytic representation. Such mitigation of data transmission burden can facilitate various enhancements to acoustic testing protocols and apparatuses as compared to other methods, e.g., to facilitate one or more of a simplified acoustic transceiver front-end configuration (e.g., relaxations to specifications related to analog-to-digital conversion, particularly amplitude resolution), higher channel counts, faster acquisition, or novel inspection system topologies. As an illustration, if a specified data transmission rate (e.g., “bandwidth”) is available, use of a phase-based technique can allow for: for the same bandwidth, a higher channel count or acquisition rate (e.g., “frame rate”) as compared to a typically available PAUT or TFM method involving full analytic signals including amplitude information and phase information.

[0008] Whether or not a binarization method is used to represent phase information, the phase-based methods described herein can include use of a phase summing technique in which amplitude information from the original time series acquisition is not required. As an illustrative example, such a phase summing technique can be used to perform one or more of A-scan reconstruction (e.g., for pulse-echo A-scan inspection) or TFM imaging. In such a phase summing method, the time series representations of phase data can be summed, e.g., where each time series can be delayed (or phase-rotated) by an appropriate delay value and then aggregated (e.g., analytically summed on a sample-by-sample basis). The time series phase data can include reconstruction of an instantaneous phase signal as described above, e.g., recovered or otherwise constructed from a compressed representation of the acquired time series phase information.

[0009] The present inventors have recognized, among other things, that, for example, at a designated focal position or positions, features on or within a test sample, when insonified, can scatter or reflect acoustic energy in a manner that produces corresponding ping signals at transducers in an acoustic probe array with coherent phases, which account for differences in time of arrival. Such phase coherence allows for aggregation (e.g., summation) of time-domain phase signal representations without the need to use amplitude information from the originally acquired A-scan ping signals. As noted above, a 1-bit sampling approach can be used, for example, to produce a signal that can be referred to as an "amplitude-less" representation of the received time-domain ping signals, for later use in such phase summation approaches. While binarization is not required to use phase data for A-scan summation or for imaging, using binarization with phase summation can increase the number of transducer arrays or simplify the receive channel structure, or both. For example, a larger number of transducers or apertures can be used for acquisition while maintaining or reducing data transfer bandwidth. In another example, the receive channel structure can be simplified, for example, by reducing the amplitude bit resolution during sampling or even eliminating multi-bit analog-to-digital conversion.

[0010] In an example, a system or apparatus can implement a technique for acoustic evaluation of a target, for example, a machine-implemented method that includes generating respective acoustic emission events via selected transmit electro-acoustic transducers of a plurality of electro-acoustic transducers, and receiving respective acoustic return signals from other receive electro-acoustic transducers of the plurality of electro-acoustic transducers in response to the respective acoustic emission events. The method can include quantizing the respective received acoustic return signals, and constructing a time-domain representation of an instantaneous phase signal from representations of at least one of the respective quantized acoustic return signals.

[0011] In an example, the method can include quantizing the received acoustic return signals using a first device, wherein the machine-implemented method includes transmitting respective representations of the quantized received acoustic return signals to a second device, and wherein constructing the time-domain representation of the instantaneous phase signal is performed on the second device for use in constructing at least one of an A-scan representation or an image.

[0012] In an example, the method can include the representation of the quantized received acoustic echo signal including data indicative of time indices of edge transitions in a binarized representation of the received acoustic echo signal. In an example, the method can include aggregating phase data from multiple quantized echo signals to generate at least one of an A-scan time series, a pixel value corresponding to a specified spatial location of a target, or a voxel value corresponding to a specified spatial location of a target. In an example, generating the pixel value or the voxel value includes performing summation of respective received acoustic echo signals using a total focusing method (TFM) technique applied to in-phase and quadrature time domain representations of the phase data.

[0013] This summary is intended to provide an overview of subject matter of the present patent application. And this summary is not intended to provide an exclusive or exhaustive explanation of the application. The DETAILED DESCRIPTION is included to provide further information about the present patent application. BRIEF DESCRIPTION OF DRAWINGS

[0014] The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0015] In the drawings, which are not necessarily to scale, like numerals can describe similar components in different views. Like numerals having different letter suffixes can represent different instances of similar components. The drawings illustrate generally, by way of example, various embodiments discussed in the present document.

[0016] Figure 1 An example is generally illustrated that includes an acoustic inspection system, which may, for example, be used to perform at least a portion of one or more techniques illustrated and described herein.

[0017] Figure 2A Another example is generally illustrated that includes a receiver signal chain, which may, for example, be included as part of an acoustic inspection system, which may, for example, be used to perform at least a portion of one or more techniques illustrated and described herein.

[0018] Figure 2B Another example is generally illustrated that includes a receiver signal chain, which may, for example, be included as part of an acoustic inspection system, which may, for example, be used to perform at least a portion of one or more techniques illustrated and described herein.

[0019] Figure 3A An illustrative example of a“raw” time series, which may, for example, correspond to an acquired A-scan signal, is generally illustrated.

[0020] Figure 3B An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 3A An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally.

[0021] Figure 3C An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 3B An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 3B An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally.

[0022] Figure 4A An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 4B An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 4C An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 4B An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 4A An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 4C An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally.

[0023] An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 4D An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 3C An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 4C An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally.

[0024] An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 5A An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 5B An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 5C An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 5B An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 5A An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 5C An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally.

[0025] An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 5D An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 4C An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 5C An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 3C An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally.

[0026] An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally. Figure 6A An illustrative example of a portion of a normalized time series and a corresponding binarized representation of the normalized time series, e.g., representing an acquired A-scan signal and a corresponding binarized representation thereof, is shown generally.

[0027] Figure 6B Another example is generally illustrated that includes a portion of a receive signal chain that can be used to provide in-phase and quadrature signals from a phase signal, including binarization of in-phase and quadrature representations, e.g., that can be used for phase-sum TFM imaging techniques.

[0028] Figure 7 An acoustic examination configuration is generally illustrated that includes an acoustic probe assembly and a target, e.g., that can use Figure 6A Illustrative examples of in-phase and quadrature signals provided by the signal chain illustrated and corresponding binarized representations of acquired time series corresponding to acquired A-scan signals.

[0029] Figure 8A An acoustic examination configuration is generally illustrated that includes an acoustic probe assembly and a target, e.g., that can use Figure 8B A representation of a focused region of an A-scan is reconstructed using a phase-based summation method illustratively shown in

[0030] Figure 8B Illustrative examples of a plurality of acquired phase signals that have been respectively delayed to provide focusing at Figure 8A regions illustrated and corresponding summation of such signals according to a phase-based summation method.

[0031] Figure 9A An acoustic examination configuration is generally illustrated that includes an acoustic probe assembly and a target, e.g., that can use Figure 9B A representation of a focused region of an A-scan is reconstructed using a phase-based summation method illustratively shown in

[0032] Figure 9B Illustrative examples of a plurality of acquired phase signals that have been respectively delayed to provide focusing at Figure 9A regions illustrated and corresponding summation of such signals according to a phase-based summation method.

[0033] Figure 10A An acoustic examination configuration is generally illustrated that includes an acoustic probe assembly and a target.

[0034] Figure 10B An acoustic examination configuration is generally illustrated that includes a superimposed TFM image constructed using a phase summation method.

[0035] Figure 10C An acoustic examination configuration is generally illustrated that includes an embedded detail region from a TFM image constructed using a phase summation method.

[0036] Figure 11 An acoustic examination configuration is generally illustrated that includes an embedded detail region from a TFM image constructed using a phase summation method. Figure 10Can illustrative example of a TFM image with embedded detail regions constructed using different variants of the phase summing approach and filtering techniques.

[0037] Figure 12 An illustrative example of a TFM image with embedded detail regions constructed using different variants of the phase summing approach and filtering techniques is generally shown from Figure 10C an illustrative example of a TFM image with embedded detail regions constructed using different variants of the phase summing approach and filtering techniques is generally shown from

[0038] Figure 13 An illustrative example of a TFM image with embedded detail regions constructed using different variants of the phase summing approach and filtering techniques is generally shown from

[0039] Figure 14 Another illustrative example of a TFM image with embedded detail regions constructed using different variants of the phase summing approach and filtering techniques is generally shown from

[0040] Figure 15 A block diagram of an example of a machine upon which any one or more of the techniques (e.g., methodologies) discussed herein can perform is shown. DETAILED DESCRIPTION

[0041] In acoustic inspection (e.g., ultrasonic inspection), as noted above, the inventors have recognized, among other things, that capturing time series A-scan data for PAUT or TFM applications can involve producing a considerable amount of data. To address various technical challenges, the inventors have recognized, among other things, that phase-based methods can be used for one or more of acquisition, storage, or subsequent analysis (e.g., A-scan reconstruction or imaging) to support acoustic inspection. Using phase-based methods can also address other technical challenges. For example, since the pulse-echo amplitude data obtained from an ultrasonic transducer array can be affected by various factors, as illustrative examples, one or more of diffraction effects (from a transmitter element, a receiver element, or a scatterer), transmission / reflection at interfaces with different constitutive properties, geometric attenuation of the signal, absorption, or frictional losses. The inventors have recognized, among other things, that the above factors affect the amplitude, and are typically compensated for by empirical measurements (e.g., using time correction gain (TCG) and angle correction gain (ACG), for example). Thus, if the received signal summation is denoted using analytical notation, the above compensation (TCG and ACG) affects the individual element amplitude term (“a qp (r)”) of the Q x P element array, where q and p represent element indices:

[0042]

[0043] In Equation 1, A(r) represents the pixel or voxel value of the spatial location described by the vector "r", a qp This represents the amplitude components of the corresponding transmit-receive pair at element indices q and p. Therefore, to address this challenge, the inventors have particularly recognized that such amplitude terms can be excluded from the summation process, leaving only the phase-dependent coherent terms to be summed.

[0044]

[0045] By using such factorization, factors affecting amplitude are suppressed (because such factors might influence terms now moved "outside" of the summation), while phase-related terms (e.g., those associated with the scatterer or other features of interest) remain unchanged. As described elsewhere in this document, individual time-domain representations of the instantaneous phase signal can be acquired, compressed, and reconstructed. Acquisition can be performed using a front-end configuration with a reduced dynamic range compared to existing methods using amplitude and phase information. Compressed representations of the instantaneously received phase signal allow for efficient transfer of acquired time-domain data between devices or functional blocks within a test or imaging system, including wired or wireless transmission of such data to other devices for further analysis, processing, or storage. Reconstruction of the representation of the instantaneous phase signal corresponding to the acquired echo signal facilitates A-scan reconstruction or imaging (e.g., TFM imaging).

[0046] Figure 1 An example including an acoustic inspection system 100 is generally shown, which can be used, for example, to perform at least a portion of one or more techniques shown and described herein. The inspection system 100 may include a test instrument 140, such as a handheld or portable component. The test instrument 140 may be electrically coupled to a probe assembly, for example, using a multi-conductor interconnect 130. The probe assembly 150 may include one or more electroacoustic transducers, such as a transducer array 152 including corresponding transducers 154A to 154N. The transducer array may follow a linear or curved profile, or may include an array of elements extending along two axes, for example, to provide a matrix of transducer elements. The space occupied by the elements does not need to be square or arranged along a straight axis. The element size and spacing may vary depending on the inspection application.

[0047] Modular probe assemblies 150 can be configured, for example, to allow test instruments 140 to be used with a variety of different probe assemblies 150. In general, transducer arrays 152 include piezoelectric transducers that can be acoustically coupled to a target 158 (e.g., a test sample or "object under test") through a coupling medium 156, for example. The coupling medium can include a fluid or gel or a solid film (e.g., an elastomer or other polymeric material) or a combination of fluid, gel or solid structures. For example, an acoustic transducer assembly can include a transducer array coupled to a wedge-shaped structure that includes a rigid thermoset polymer with known acoustic propagation characteristics (e.g., available from C-Lec plastics, Inc. ), and water can be injected between the wedge and the structure under test as the coupling medium 156 during testing.

[0048] Test instruments 140 can include digital and analog circuitry, for example, front-end circuitry 122 including one or more transmit signal chains, receive signal chains or switching circuitry (e.g., transmit / receive switching circuitry). Transmit signal chains can include amplifier and filter circuitry, for example, to provide transmit pulses for transmission through interconnects 130 to probe assemblies 150 for acoustic transmission into a target 158, for example, to image or otherwise detect defects 160 in or on a structure of a target 158 by receiving acoustic energy in response to scattering or reflection induced by the acoustic transmission.

[0049] While Figure 1 A single probe assembly 150 and a single transducer array 152 are shown, other configurations can also be used, for example, multiple probe assemblies connected to a single test instrument 140 or multiple transducer arrays 152 used with a single or multiple probe assemblies 150 for in-line inspection. Similarly, coordination between multiple test instruments 140 can be used to perform a test protocol, for example, in response to an overall test plan established from a host test instrument 140 or established by another remote system (e.g., computing facility 108 or a general purpose computing device such as a laptop computer 132, tablet computer, smart phone, desktop computer, etc.). As an illustrative example, a test plan can be established according to a published standard or regulatory requirement and can be performed upon initial development or on a repeated basis for ongoing monitoring.

[0050] The receive signal chain of the front-end circuit 122 can include one or more filter or amplifier circuits and an analog-to-digital conversion facility, for example, to digitize echo signals received using the probe assembly 150. The digitization can be performed coherently, for example, to provide multiple channels of digitized data that are aligned or referenced to one another in time or phase. The front-end circuit can 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 can be coupled to a memory circuit, for example, to execute instructions that cause the test instrument 140 to perform one or more of acoustic transmission, acoustic acquisition, processing, or storage of data related to an acoustic inspection or otherwise perform techniques as shown and described herein. The test instrument 140 can be communicatively coupled to other portions of the system 100, for example, using a wired or wireless communication interface 120.

[0051] Performance of one or more techniques as shown and described herein, for example, can be implemented on-board the test instrument 140 or using other processing or storage facilities, for example, using the computing facility 108 or a general purpose computing device such as a laptop computer 132, tablet computer, smart phone, desktop computer, or the like. For example, processing tasks that would be very slow or beyond the capabilities of the test instrument 140 if performed on-board the 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 (e.g., A-scan matrices of time series data or compressed phase data) can be implemented using a remote facility communicatively coupled to the test instrument 140, for example. The test instrument can include a display 110, for example, for presenting configuration information or results, and an input device 112, for example, including one or more of a keyboard, trackball, function or soft keys, mouse interface, touch screen, stylus, or the like, for receiving operator commands, configuration information, or responses to queries.

[0052] Figure 2AAn example is generally shown that includes a receiver signal chain 200, which for example can be included as part of an acoustic inspection system 100, which for example can be used to perform at least a portion of one or more of the techniques shown and described herein. The signal chain 200 of FIG. 2 can be used to perform, for example, phase summing imaging techniques according to various examples shown and described in this document. Generally, the signal chain 200 as shown in FIG. 2 can receive a time-domain pulse echo y(t), for example received by a transducer in an array of acoustic transducers used for PAUT or TFM imaging. An amplifier 202 can be included as part of an analog front-end circuit 210. The amplifier can be coupled to an analog-to-digital converter. For example, a single-bit (i.e., “1-bit”) quantization or “binarization” of the received pulse echo signal “y(t)” can be performed using a comparator circuit 204. The digital representation of the pulse echo signal can be provided to a digital block 220 of the receive signal chain 200, for example to perform edge identification (e.g., identify the time position of edge transitions in the digital representation of the pulse echo signal) at 206. At 208, a phase estimation method corresponding to the first technique or the second technique described herein at Figure 4A 、 Figure 4B and Figure 4C or Figure 5A 、 Figure 5B or Figure 5C may be implemented. The result estimates (e.g., “reconstruction”) of the instantaneous phase signal may be processed, for example by a Hilbert transform or other techniques, to provide in-phase “I” and quadrature “Q” time-domain signals. The time-domain signals generated from the estimated instantaneous phase signal can be used to perform imaging via TFM at 212 in a manner similar to commonly available TFM imaging, but without the need for full A-scan amplitude data from, for example, raw acquired pulse echo signals (e.g., basic A-scan pulse echo signals) represented by a set of signals similar to y(t). At 214, further processing of the TFM image can be implemented, for example to perform one or more of gamma correction or spatial filtering or to perform application of another volume-averaging mask to produce a TFM image at 216 based on the phase summing technique.

[0053] Figure 2AThe analog front-end circuit 210 can be replicated, for example, to provide a number of channels corresponding to the number of elements in the transducer array, or the front-end circuit 210 can be shared or multiplexed for acquiring pulse-echo signals from multiple transducer elements, for example, in a time-interleaved fashion. As an illustrative example, the analog front-end circuit 210 can include a low-noise amplifier with 37 decibel (dB) (+74x) gain, for example, using an LT1806 integrated circuit available from Analog Devices (Woburn, MA), which can provide a 325 MHz gain-bandwidth product, 140 volts per microsecond slew rate, and 85 milliamp output current. Binarization can be performed, for example, using an LT1719 integrated comparator circuit, also available from Analog Devices (Woburn, MA). The comparator circuit 204 can provide hysteresis, for example, to suppress unwanted output transitions due to noise. The analog front-end circuit 210 or a portion of the front-end circuit 210 can include a standby or shutdown capability, for example, to enter a near-zero or zero current consumption mode when not being used for acquisition. In this way, as an illustrative example, a portable or handheld inspection instrument housing the front-end circuit 210 can be powered by a battery, and operational energy can be conserved to extend the operational life between recharges, or for the same battery life, a higher number of channels can be supported, as compared to other approaches.

[0054] A portion or all of the processing performed in the digital block 220 need not be performed on the same physical device or instrument used for acquisition. For example, after binarization by the comparator circuit 204, a representation of the binarized pulse-echo signals can be transmitted to another device or component for downstream processing. Similarly, the output from edge identification at 206 can be referred to as a “compressed” representation of the phase data corresponding to the binarized pulse-echo signals. The compressed representation can be transmitted to another device or component for downstream processing.

[0055] Figure 2B Another example is generally shown including a receiver signal chain 240, for example, which can be included as part of an acoustic inspection system, and which can be used to perform at least a portion of one or more of the techniques shown and described herein. As compared to the example of Figure 2A As compared to the example of Figure 2BIn some embodiments, a coherent receiver topology is used. The pulse echo signal y(t) can be provided to respective mixer circuits 222A and 222B, e.g., to downconvert the pulse echo signal y(t) to a desired frequency range at or near the baseband frequency range using a local oscillator 218. Unwanted harmonics or modulation products can be suppressed, e.g., using the shown low pass filter circuits. The resulting in-phase and quadrature signals can be processed at 224, either in the analog domain or via digitization and then digital processing (e.g., using CORDIC, look-up tables, or other techniques) to provide an amplitude representation E(t) and an instantaneous phase representation The instantaneous phase representation can be used for summed A-scan construction or TFM imaging, or can be compressed, transmitted, or stored, as in other examples in this document.

[0056] Figure 2A and Figure 2B Examples relate to receive circuitry and processing techniques that can be used with phase-summing methods. The inventors have recognized, among other things, that the above receiver topology can also facilitate the use of a modified transmit scheme. For example, the transmit pulse amplitude can be reduced compared to other methods, as the dynamic range associated with using a single-bit quantization receive method can be reduced compared to using a corresponding high-resolution amplitude sampling using a multi-bit analog-to-digital conversion. As an exemplary enhancement, using a lower transmit amplitude can facilitate a higher number of channels and a more compact transmit circuitry or transducer geometry compared to the generally available methods involving summed A-scan or TFM imaging without the use of phase-summing.

[0057] Figure 3A An illustrative example of a "raw" experimentally obtained time series, e.g., corresponding to a pulse echo (e.g., "A-scan") signal acquired without binarization, is shown generally. The amplitudes are expressed in arbitrary units, and the time series is not normalized by amplitude. Figure 3B A portion of a normalized time series 392, e.g., corresponding to the time series of Figure 3A A portion of a normalized time series 392, e.g., corresponding to the time series of B (t) is generated using the following analytical expression, where:

[0058] y B (t) = 1 when y(t) > 0 and y B (t) = 0 when y(t) < 0:

[0059]

[0060] For a y(t) value that is exactly zero, as an example, the result can be specified as 0; or as another example, the result can be specified as 1. The magnitude of the binarized representation is normalized to a value of 0 or 1, but can be appropriately scaled, gated, or otherwise adjusted to provide voltage-mode or current-mode digital signals with desired logic high and logic low levels for downstream processing.

[0061] Figure 3C Generally shown Figure 3B A portion of the normalized time series 392 Figure 3B An illustrative example of the corresponding binarized representation 394 of the normalized time series and the corresponding instantaneous phase signal 396. The inventors have particularly recognized that the instantaneous phase signal 396 exhibits approximately piecewise linear behavior during the corresponding “pseudo” period, where the period is defined by a approximately linear phase transition between values ​​of -π radians and +π radians. This behavior exists in part because the pulse echo signal is a relatively narrow-band signal with an offset around the center frequency. This piecewise behavior facilitates the use of a first phase construction technique or a second phase construction technique as described below. The term “construction” can refer to “reconstructing” or “recovering” phase data from a compressed representation of the time-domain instantaneous phase signal. Thus, using the summation of the time-domain phase signal, the constructed representation of the time-domain instantaneous phase signal can be used for summation-based A-scan construction or TFM imaging. For example, the time-domain representation of the reconstructed instantaneous phase signal can be aggregated (e.g., coherent summation), including aggregating phase data from multiple quantized echo signals to generate at least one of an A-scan time series, pixel values ​​corresponding to a specified spatial location of the target, or voxel values ​​corresponding to a specified spatial location of the target, such as a test sample.

[0062] Figure 4A , Figure 4B and Figure 4C Generally speaking, they all show what can be used to binarize time series (such as...) Figure 4B The transitions (e.g., rising edges) in the data from the acquired time series (as shown) Figure 4A The binary representation of the instantaneous phase signal (as shown) is used to construct the instantaneous phase signal (e.g.) Figure 4C The first technique (shown) represents the first technology. In the first technique, processing can be performed. Figure 4A The binary representation of y B (t), for example, to detect such as Figure 4B The simulation of the Dirac distribution d1(t) shows the time position of the rising edge transition. Typically, the instantaneous phase can be modeled as a piecewise linear approximation, which has the following characteristics defined by y. BThe phase changes by 2π radians per pseudo-period between the time indices of adjacent rising edges in (t). In practical applications, a threshold comparator or a binarized signal y can be used. B Digital signal processing of the digital representation of (t) is used to detect y. B The edges in (t), for example, using finite difference techniques to estimate y B The derivative of (t). Figure 4C The phase in can be used from Figure 4B The edge data is used to generate and can model or otherwise represent the estimate of the "in-phase" component of the instantaneous phase of the acquired pulse signal as an analytical representation. For example, a phase estimate can be established. From and Figure 4A The time t corresponding to the first rising edge transition in the middle n-1 The value of -π / 2 radians at that point varies linearly (e.g., the slope is defined) to the value of -π / 2 radians. Figure 4A The time t corresponding to the transition of the second adjacent rising edge in the middle n The value of +3π / 2 radians at point t is defined as a segment using a piecewise approximation. For all adjacent rising edges on t n and t n-1 Phase estimation It can be parsably represented as:

[0063]

[0064] Figure 4D Generally shown Figure 3C The instantaneous phase actually acquired before binarization 450, as shown earlier, is... Figure 4C The representation of the instantaneous phase 452 constructed in the middle A comparison between the two. The recovered phase 452 reasonably tracks the value of the instantaneous phase 450, and is therefore suitable for use in phase-summing techniques such as summation in A-scan construction or TFM imaging via phase summation. As described elsewhere in this document, with respect to transmission, storage, or manipulation... Figure 3A Pulse echo time domain signal or Figure 4D Compared to the complete time series record corresponding to the instantaneous phase 450 shown, Figure 4B The temporal location of the edge transitions shown can be used to encode phase information in a highly compressed form for transmission, storage, or downstream processing. As mentioned elsewhere, summative A-scan or TFM imaging techniques typically involve the use of many such pulse-echo time-series records, thus the savings in bandwidth or data volume have a multiplicative effect as the number of transducers or apertures increases.

[0065] Figure 5A , Figure 5B and Figure 5C Generally speaking, they all show what can be used to binarize time series (such as...)Figure 5B The transitions (e.g., edges) in the data obtained from the time series (as shown) Figure 5A The binary representation of the instantaneous phase signal (as shown) is used to construct the instantaneous phase signal (e.g.) Figure 5C The second technique (shown) is similar to the first technique. The reconstructed representation of the instantaneous phase signal varies within a 2π radian range between -π / 2 radians and +3π / 2 radians within a period defined as the binarized representation y of the acquired pulse echo signal. B The duration between adjacent rising edge transitions in (t). Compared to the first technique discussed above, the second technique constructs a structure by dividing the corresponding period between adjacent rising edge transitions into two sub-periods that define different segments (e.g., segments with different slopes). Figure 5C The phase shown is a piecewise linear approximation.

[0066] For example, such as Figure 5A As shown schematically, as Figure 5B As shown, at time t 2n-1 Detect the rising edge transition in the binarized signal and trigger it. Figure 5C Reconstructing instantaneous phase Reset to a value of -π / 2 radians. For example... Figure 5B As shown, at time t 2n Inspection Figure 5A The binarized representation in the next adjacent falling edge transition, and by changing the phase from t 2n-1 The value at t changes linearly by -π / 2 radians (e.g., defining the slope) to t. 2n To establish the value at the location + π / 2 Figure 5C Instantaneous phase Thus, the first sub-period is defined. At time t... 2n+1 The duration between a falling edge transition and the next adjacent rising edge transition is defined as t. 2n The phase value π / 2 at t 2n+1 A linear transition between the phase value at +3π / 2 is used to define the second sub-period, where the first and second sub-periods form a complete pseudo-period. For example, in... Figure 4B In the example, Figure 5B The representation in can be represented in Figure 5A The binary representation of y B The Dirac distribution d2(t) at the moment when the rising edge transition or falling edge transition occurs. Figure 5B and Figure 5C The waveform shown is simulated, and the instantaneous phase is reconstructed. This can be represented analytically as follows (e.g., for each group from rising edge to falling edge to the next rising edge):

[0067]

[0068] in:

[0069]

[0070] as well as

[0071]

[0072] Figure 5D Generally shown Figure 3C The instantaneous phase actually acquired before binarization 450, as shown earlier in the text. Figure 4C The representation of the instantaneous phase 452 constructed using the first technique. as well as Figure 5C Another representation of the instantaneous phase 454 constructed using the second technique. A comparison between the two. Both the recovered phases 452 and 454 reasonably track the value of the instantaneous phase 450, with the second technique used to provide phase 454 resulting in a better approximation of the instantaneous phase 450 before binarization, at the cost of slightly higher reconstruction complexity.

[0073] Figure 6A An example including a portion of a receive signal chain 600A is generally shown. This receive signal chain 600A can be used to provide in-phase and quadrature signals from a phase signal; for example, it can be used in phase-summing TFM imaging techniques. As mentioned above, certain imaging or processing techniques may include in-phase and quadrature representations using acquired time-domain pulse-echo imaging data. In the phase-based methods described herein, in-phase “I” (y) signals can be generated from the representation of the instantaneous phase. I (t) signal and orthogonal "Q" (y Q (t) signal, for example, by Figure 2B The phase signal provided by the receiver structure shown (Apply the Hilbert transform to the acquired A-scan time series data y(t) to obtain the instantaneous phase corresponding to each acquired A-scan time series) (as discussed further below) or the reconstructed phase signal corresponding to the first or second technique described above. or The resulting in-phase and quadrature signals (e.g., time-series representations in the digital domain) can be provided at 212 for TFM imaging, and at 214 for further processing such as gamma correction or filtering. The inventors have recognized that binarization methods for signal acquisition can be applied to phase-based imaging, such as... Figure 6B As shown, Figure 6B Another example, generally showing at least a portion of the receive signal chain 600B, is illustrated.Figure 6B In particular, the comparators 226A and 226B can be used to quantize (e.g., binarize) the in-phase and quadrature representations of the reconstructed phase signal, such as or and the resulting "square" representations can be used to provide phase sum imaging in a similar manner as Figure 6A In yet another example, the phase estimates provided using the Hilbert transform can also be provided as input to the I / Q forming block shown. The binarized or "square" in-phase and quadrature signals are given by: Figure 6B

[0074]

[0075] and

[0076]

[0077] In yet another approach, the phase values from the unit circle representation can be used to establish quantized (e.g., binarized representations) of the in-phase and quadrature signals, for example using a look-up table or similar technique to assign. As an illustrative example, such a technique can replace the sine and cosine functions in Figure 6A or Figure 6B For example, the values of y I (t) and y Q (t) can be assigned based on the range of the phase values in the input instantaneous phase signal as follows:

[0078]

[0079] Table 1. binarized in-phase and quadrature signal values for respective phase ranges.

[0080] Figure 7 Generally, illustrative examples are shown of the time-domain in-phase 772 and quadrature 774 signals that can be provided, for example, using the signal chain shown in Figure 6A and the corresponding binarized representations 770 of the time series acquired, to illustrate the p-radian phase relationship between the in-phase and quadrature signals and the relative phase in the binarized representations 770 that defines the period of the respective in-phase 772 and quadrature 774 signals and the edge transitions.

[0081] The phase summing approaches described herein thus far can be used to support a variety of analysis or imaging techniques. For example, summing A-scan generation can be performed, for example, by summing time-domain phase representations acquired (e.g., using PAUT methods) from multiple transducers or multiple transducer apertures.

[0082] ​Figure 8A An acoustic inspection configuration 1100 is generally shown, including an acoustic probe assembly 150 and a target 158 (e.g., a block with side-drilled holes or "SDH" block) and a representation of a focal region 1182A for reconstructing a summed A-scan 1184A using a phase-based summation method schematically shown in Figure 8B A phase-based summation method is schematically shown in Figure 8A Each ray 1180A representing a direction of propagation of a reflected ultrasound wave can be acquired by an ultrasound transducer array included as part of the probe assembly 150. In Figure 8A In the example 1182A, the rays 1180A are used to determine a delay value for each acquired A-scan time series to create a focal region 1182A that is well aligned with the defect 160 location. Such an example is merely illustrative, and a transmit focusing approach can also be used in addition to or instead of receiving side beamforming.

[0083] Referring to Figure 8B A plurality of instantaneous phase signals 1196A corresponding, for example, to different receive transducers or receive apertures are acquired, with each phase signal being delayed as described above to establish the focal region 1182A. The resulting plurality of phase signals 1196A are then coherently summed, for example on a sample-by-sample basis, to provide a time-domain summed A-scan 1184A. Because amplitude information is not preserved, the A-scan exhibits little amplitude shift outside of a region 1198A that is coherent in phase with the defect 160 in the focal region 1182A. As noted elsewhere, using phase data instead of raw A-scan time series data can provide various enhancements in data volume or measurement throughput, or can simplify receiver configurations, as illustrative examples.

[0084] Figure 9A An acoustic inspection configuration 1100 is generally shown, including an acoustic probe assembly 150 and a target 158 and a representation of a focal region 1182B for reconstructing a summed A-scan using a phase-based summation method schematically shown in Figure 9B In Figure 9A In contrast to the example 1182A of Figure 8A the focal region 1182B is not well aligned with the defect 160 in the SDH block. Figure 9B A plurality of instantaneous phase signals 1196B acquired from the probe assembly 150 are generally shown, having been respectively delayed to establish a focal region 1182B in Figure 9AAn illustrative example of a plurality of acquired phase signals 1196B that are focused at region 1182B is shown, along with a corresponding summation 1184B of such signals according to a phase-based summation method. Phase coherence is still visible in region 1198B, but the phase coherence is weaker because the focused region 1182B is not well aligned with the defect 160 (and the corresponding defect echo portion of each signal 1196B is not in time alignment after the delay is applied, as shown by the dashed curve). The present inventors have recognized that such behavior can be addressed by computing a series of A-scan summations at different focused positions within the target Figure 8B the summation 1184A and Figure 9B the summation 1184B.

[0085] Other techniques can be used to separate the region of weak phase coherence in region 1198B from other portions of the summed A-scan 1184B. For example, a spatial noise distribution within the target 150 can be established empirically or through an analytical model. Values in the summed A-scan 1184B can be adjusted based on the probability that an amplitude value in the sum corresponds to noise versus a defect or other feature of interest, or such adjustment can be performed in the respective received signals of the plurality of phase signals 1196B, for example suppressing contributions in regions or ranges of amplitudes that the distribution indicates are likely to be noise.

[0086] Other methods can be used, for example by determining a moment of a statistical distribution corresponding to the respective spatial position, for example a variance, skewness, or kurtosis (or a time index in the case of a summed A-scan), and using such determination to set a threshold applied to the constituent phase signals 1196B below which any contribution to the sum will be ignored or de-weighted. Such statistical methods based on noise distributions are also believed to be applicable to TFM imaging methods involving phase summation, where pixel or voxel values (e.g. brightness values) can be adjusted accordingly.

[0087] Figure 10A An acoustic inspection configuration is generally shown, including an acoustic probe assembly 150 and a target 158 (including a side-drilled hole or “SDH” block), for obtaining experimental data as discussed in various examples below. The probe assembly is an Olympus 5L64-A32 probe, with the first 32 elements used, with a 5 MHz transmit center frequency used to excite the probe, a 0.5 millimeter transducer pitch, a 10 millimeter transducer elevation, an outer dimension of 40 millimeters by 28 millimeters in the plane of the transducer array, and a height of 26 millimeters. Figure 10BThe acoustic inspection configuration, which includes an overlay TFM image 1000A constructed using a phase summation method, is generally shown to illustrate the relationship between features shown in the TFM image 1000A and the location of defects in target 158. Figure 10C Broadly speaking, it shows including from Figure 10B Acoustic inspection configuration of embedded detail region of TFM image 1000A and 1000B. Figure 10B The TFM image 1000A was constructed using a phase summation method. The embedded detail region 1000B is used to illustrate qualitative variations between different applications of the phase summation method in the other examples below.

[0088] Figure 11 This broadly illustrates the different variants of the phase summation method used to construct data from... Figure 10C An illustrative example of a TFM image with embedded detail regions. A reference implementation of the phase summation method may include: coherently summing the time-domain phase signal in a manner similar to processing a fully analytical representation of the acquired A-scan, but using only the time-domain representation of the instantaneous phase. In the reference implementation, A-scans are experimentally acquired using 32 apertures as described above, and a Hilbert transform is applied to the acquired A-scan time-series data y(t) using the following expression to obtain the instantaneous phase corresponding to each acquired A-scan time-series.

[0089]

[0090] In other examples, the in-phase y-coordinate of the instantaneous phase of the Hilbert transform can be constructed. IH (t) represents orthogonal to y QH (t) represents, and then in phase y IH (t) represents orthogonal to y QH (t) indicates that the phase signal is provided for TFM imaging as if the acquired phase signal were A-scan time-series data:

[0091]

[0092]

[0093] exist Figure 11 (a) shows the obtained phase-sum TFM image of the embedded region (including SDH defects), and (b) and (c) show TFM images constructed using the first technique or the second technique, respectively, to recover the instantaneous phase signal. and By comparison, Figure 11 The second technology shown in (c) produces something more closely similar to Figure 11the reference image in (a), but the two images in (b) and (c) generally show the same defect locations and other image features (in the center of each image). As other examples, as described above with respect to Figure 6B The use of the binarized I / Q representation or the "square" I / Q representation as described above with respect to the receiving scheme of Figure 11 The TFM images in (d) and (e) of show considerable roughness compared to the reference image in (a) of Figure 11 The TFM images in (d) and (e) of show considerable roughness compared to the reference image in (a) of Figure 11 The TFM images in (d) and (e) of show considerable roughness compared to the reference image in (a) of Figure 12 An illustrative example of a TFM image from the embedded detail region of Figure 10C is constructed using different variants of the phase summation method and filtering techniques. Figure 11 The images of (a), (b), (c), (d), and (e) of are constructed in a similar manner as the corresponding examples in Figure 12 However, in Figure 11 each image is gamma corrected and low pass filtered. The low pass filtering is performed using a two-dimensional convolution using a kernel of

[0094]

[0095] Generally, then Figure 12 and Figure 11 The experimentally obtained A-scan data and the resulting phase summation imaging of the examples of show that the phase summation method can be used to provide TFM imaging using either the sampled instantaneous phase signals or the reconstructed instantaneous phase signals, where defects such as side-drilled holes in the test block target are evident.

[0096] Figure 12A technique 1300, e.g., a method, is generally shown that includes acquiring and digitizing acoustic echo signals and constructing a time-domain representation of an instantaneous phase signal. At 1320, acoustic transmission events can be generated, e.g., corresponding to a transmission excitation of one or more transducers in an ultrasonic transducer array. At 1325, in response to respective transmission events, respective acoustic echo signals can be received. Such acoustic echo signals can correspond to A-scan signals. At 1330, respective received acoustic echo signals can be quantized, e.g., to provide a discrete-time representation or a digitized representation of the received acoustic echo signals. The discrete-time representation or digitized representation can be transmitted elsewhere for further processing, or other data indicative of the discrete-time representation or digitized representation, e.g., time locations of edge transitions, can be transmitted elsewhere. At 1335, a time-domain representation of an instantaneous phase signal can be constructed from the representation of at least one respective quantized acoustic signal. For example, such a time-domain representation can be constructed using the first phase signal construction technique or the second phase signal construction technique discussed in detail above, or other techniques. Optionally, at 1340, phase data (e.g., reconstructed time-domain representations of instantaneous phase signals) can be aggregated from multiple acquired and quantized echo signals to generate at least one of an A-scan time series (e.g., summed A-scans) or a pixel value or a voxel value corresponding to a specified spatial location of a target (e.g., as in a TFM imaging method using phase summation). Figure 13 、 Figure 4A 、 Figure 4B 、 Figure 4C 、 Figure 5A or Figure 5B

[0097] Figure 5C ​Another technique 1400, such as another method, is generally shown, and includes acquiring and single-bit quantizing (e.g., binarizing) an acoustic echo signal and generating a representation of the received acoustic echo signal that includes data indicative of time indices of edge transitions in the binarized acoustic echo signal. At 1420, an acoustic transmission event can be generated, e.g., corresponding to a transmission excitation of one or more transducers in an ultrasonic transducer array. At 1425, in response to the respective transmission event, a respective acoustic echo signal can be received. Such an acoustic echo signal can correspond to an A-scan signal. At 1430, the respective received acoustic echo signal can be acquired and single-bit quantized to provide a binarized representation of the received acoustic echo signal. The binarized representation can be transmitted elsewhere for further processing, or other data indicative of a discrete-time representation or digitized representation, such as time locations of edge transitions, can be transmitted elsewhere. For example, at 1435, data indicative of edge transitions in the binarized representation of the received acoustic echo signal can be generated (e.g., edge transitions can be detected, and time indices of such transitions can be encoded). Optionally, at 1440, phase data (e.g., a reconstructed time-domain representation of an instantaneous phase signal from the encoded data generated at 1435) can be aggregated from multiple acquired and quantized echo signals to generate at least one of an A-scan time series (e.g., a summed A-scan) or a pixel or voxel value corresponding to a specified spatial location of a target (e.g., as in a TFM imaging method using phase summation).

[0098] Figure 14 A block diagram of an example of a machine 1500 is shown, including the example of a machine upon which any one or more of the techniques (e.g., methodologies) discussed herein can perform. In various examples, the machine 1500 can operate as a standalone device or can be connected (e.g., networked) to other machines. In a networked deployment, the machine 1500 can operate in the capacity of a server machine, a client machine, or both in server-client network environments. In an example, the machine 1500 can act as a peer machine in peer-to-peer (P2P) (or other distributed) network environment. The machine 1500 can be a personal computer (PC), a tablet device, a set-top box (STB), a personal digital assistant (PDA), a mobile telephone, a web appliance, a network router, switch or bridge, or any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that machine. Further, while only a single machine is illustrated, the term "machine" shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein, such as cloud computing, software as a service (SaaS), other computer cluster configurations, or the like.

[0099] As described herein, examples can include, or operate by, logic or a number of components, or mechanisms. Circuitry is a collection of circuits implemented in tangible entities that include hardware (e.g., simple circuits, gates, logic, etc.). Circuitry includes components such as processors, microprocessors, circuits, circuitry, circuit components, integrated circuits, etc. that work together to cause a device to do work. A combination of hardware and software can be a circuit. In examples, a hardware component can include a processor that comprises simple instructions to do

[0100] The machine (e.g., computer system) 1500 can include a hardware processor 1502 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory 1504 and a static memory 1506, some or all of which can communicate with one another via an interlink (e.g., bus) 1530. The machine 1500 can further include a display unit 1510, an alphanumeric input device 1512 (e.g., a keyboard), and a user interface (UI) navigation device 1514 (e.g., a mouse). In an example, the display unit 1510, input device 1512 and UI navigation device 1514 can be a touch screen display. The machine 1500 can additionally include a storage device (e.g., drive unit) 1516, a signal generation device 1518 (e.g., a speaker), a network interface device 1520, and one or more sensors 1521, such as a global positioning system (GPS) sensor, compass, accelerometer, or other sensor. The machine 1500 can include an output controller 1528, 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 or control one or more peripheral devices (e.g., a printer, card reader, etc.).

[0101] The storage device 1516 can include a machine readable medium 1522 on which is stored one or more sets of data structures or instructions 1524 (e.g., software) embodying any one or more of the techniques or functions described herein, or by any one or more of the techniques or functions described herein. The instructions 1524 can also reside, completely or at least partially, within the main memory 1504, within static memory 1506, or within the hardware processor 1502 during execution thereof by the machine 1500. In an example, one or any combination of the hardware processor 1502, the main memory 1504, the static memory 1506, or the storage device 1516 can constitute machine readable media.

[0102] While the machine readable medium 1522 is illustrated as a single medium, the term“machine readable medium” can include a single medium or multiple media (e.g., a centralized or distributed database, and / or associated caches and servers) configured to store the one or more instructions 1524.

[0103] The term "machine-readable medium" can include any medium that is capable of storing, encoding, or carrying instructions for execution by the machine 1500 and that cause the machine 1500 to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding or carrying data structures used by or associated with such instructions. Non-limiting machine-readable medium examples can include solid-state memories, and optical and magnetic media. Thus, a machine-readable medium can not be a transitory propagating signal. Specific examples of a machine-readable medium can include: nonvolatile memory, such as semiconductor memory devices (e.g., Electrically Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM)) and flash memory devices; magnetic or other

[0104] The instructions 1524 can further be transmitted or received over a communications network 1526 using a transmission medium via the network interface device 1520 utilizing any one of a number of transfer protocols (e.g., frame relay, internet protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Example communication networks can include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), mobile telephone networks (e.g., a cellular network, such as one utilizing one or more standards such as 4G standards or Long Term Evolution (LTE)), plain old telephone (POTS) networks, and wireless data networks (e.g., Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards known as Wi-Fi®, IEEE 802.15.4 family of standards, peer-to-peer (P2P) networks, among others). In an example, the network interface device 1520 can include one or more physical jacks (e.g., Ethernet, coaxial, or phone jacks), or one or more antennas to connect to the communications network 1526. In an example, the network interface device 1520 can include a plurality of antennas to wirelessly communicate using at least one of single-input multiple-output (SIMO), multiple-input multiple-output (MIMO), or multiple-input single-output (MISO) techniques. The term "transmission medium" shall be taken to include any intangible medium that is capable of storing, encoding or carrying the instructions for execution by the machine 1500, and includes digital or analog communications signals or other intangible media to facilitate communication of such software.

[0105] Figure 15 Various annotations

[0106] ​The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the application can be practiced. These embodiments are also referred to as "examples." Such examples can include elements in addition to those shown or described. However, the present inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the present inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof).

[0107] In the event that the use of a term in the present document is inconsistent with the use of that term in any document incorporated herein by reference, the use in the present document controls.

[0108] In the present document, the terms "a" or "an" are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of "at least one" or "one or more." In the present document, the term "or" is used to refer to a nonexclusive or, such that "A or B" includes "A but not B," "B but not A," and "A and B," unless otherwise indicated. In the present document, the terms "including" and "including in which" are used as plain English equivalents of the respective terms "comprising" and "wherein." Additionally, in the appended claims, the terms "including" and "comprising" are open-ended, that is, a system, device, article, composition, formulation, or process that includes elements in addition to those listed after such open-ended terms in a claim are still deemed to fall within the scope of that claim. Moreover, in the appended claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

[0109] The method examples described herein can be machine or computer- implemented at least in part. Some examples can include a computer- or machine- readable medium or machine-readable storage encoded with instructions that, when executed, cause an electronic device to perform methods as described in the above examples. Implementations of the methods described above can include code, such as microcode, assembly language code, a higher-level languages code, or the like. Such code can include computer readable instructions for performing various methods. The code can form portions of computer program products. Further, in an example, the code can be tangibly embodied on one or more volatile or non-volatile tangible computer-readable media. Examples of these tangible computer-readable media can include, but are not limited to, volatile media, non-volatile media, removable media, non-removable media, and / or the like. Examples of volatile media can include, but are not limited to, RAM, dynamic RAM, static RAM, static RAM, fast page mode RAM, etc. Examples of non-volatile media can include, but are not limited to, ROM, programmable ROM, erasable programmable ROM, electrically erasable programmable ROM, flash memory, hard disks, or the like. Examples of removable media can include, but are not limited to, floppy disks, magnetic tape, optical disk, optical tape, etc. Examples of non-removable media can include, but are not limited to, ROM, as discussed above. Likewise, examples of both removable and non-removable media can include, but are not limited to, magnetic disks, optical disks, magnetic cassettes, memory cards, memory sticks, etc. These examples should not be limiting, further, such computer-readable media can store data which is accessible by a computer, the data

[0110] The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) can be used in combination with each other. Other implementations can be used by those of ordinary skill in the art upon reviewing the above description. The Abstract is provided to allow a reader to quickly ascertain the nature of the technical disclosure. The submission of the Abstract is optional, and it is not intended to limit the scope or meaning of the claims. Additionally, in the above Detailed Description, various features can be grouped together or described in a single implementation for the purpose of streamlining the disclosure. This should not be interpreted as intending that the claimed subject matter requires more features than are expressly identified in the claims. Rather, the inventive subject matter can lie in less than all features of a particular disclosed implementation. Thus, the following claims are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate implementation with the scope of the features of the claims being those features that are expressly identified in the claim. The scope of the inventive subject matter is meant to be interpreted in the broadest sense and is intended to include all implementations of the claims that have been set forth along with combinations of such claims with each other and with other claims falling within the scope of the inventive subject matter.

Claims

1. A machine-implemented method for acoustic evaluation of a target, the method comprising: generating respective acoustic launch events via selected transmit electro-acoustic transducers of a plurality of electro-acoustic transducers; receiving respective acoustic echo signals from other receive electro-acoustic transducers of the plurality of electro-acoustic transducers in response to the respective acoustic launch events; single-bit quantizing the respective received acoustic echo signals to provide a binary representation of the received acoustic echo signals; and constructing a time-domain representation of an instantaneous phase signal from at least one of the respective quantized acoustic echo signal representations, wherein the quantized received acoustic echo signal representation comprises data indicative of time indices of edge transitions in the binary representation of the received acoustic echo signal, wherein the time-domain representation of the instantaneous phase signal comprises a piecewise construction, and wherein slopes of segments in the piecewise construction are established at least in part by determining durations between adjacent transitions of the quantized representation of the acoustic echo signal.

2. The machine-implemented method of claim 1, wherein, performing the quantizing of the respective received acoustic echo signals using a first device; wherein the machine-implemented method comprises transmitting the respective quantized received acoustic echo signal representations to a second device; and wherein constructing the time-domain representation of the instantaneous phase signal is performed on the second device for constructing at least one of an A-scan representation or an image.

3. The machine-implemented method of claim 1, comprising: aggregating phase data from a plurality of quantized echo signals to generate at least one of an A-scan time series, pixel values corresponding to a specified spatial location of the target, or voxel values corresponding to the specified spatial location of the target.

4. The machine-implemented method of claim 3, wherein, generating pixel values or voxel values comprises performing summation of the respective received acoustic echo signals using total focusing method (TFM) techniques applied to in- phase and quadrature time-domain representations of the phase data.

5. The machine-implemented method of claim 4, wherein, generating the respective acoustic launch events via selected transmit electro-acoustic transducers of the plurality of electro-acoustic transducers and receiving the respective acoustic echo signals from other receive electro-acoustic transducers of the plurality of electro-acoustic transducers in response to the respective acoustic launch events comprises performing a full matrix capture (FMC) acquisition, the respective acoustic echo signals comprising A-scans corresponding to respective elements of a matrix of received signals.

6. The machine-implemented method of claim 4, comprising: generating imaging data comprising a plurality of generated pixel values or voxel values, the plurality of generated pixel values or voxel values generated using total focusing method (TFM) applied to respective in-phase and quadrature time-domain representations of phase data; and applying a mask to the imaging data.

7. The machine-implemented method of any one of claims 3 to 6, comprising: establishing a noise distribution corresponding to a region of interest containing the specified spatial location.

8. The machine-implemented method of any one of claims 3 to 6, comprising: adjusting pixel amplitude values or voxel amplitude values based on a probability of an amplitude value corresponding to noise.

9. The machine-implemented method of any one of claims 3 to 6, comprising: suppressing or inhibiting contribution of pixel values or voxel values corresponding to noise.

10. The machine-implemented method of any one of claims 3 to 6, wherein, generating pixel values or voxel values corresponding to a specified spatial location of the target comprises applying a moment of a statistical distribution to respective pixel values or voxel values.

11. The machine-implemented method of claim 10, wherein, the moment corresponds to a variance.

12. The machine-implemented method of any one of claims 3 to 6, wherein, Aggregating the phase data includes generating in-phase and quadrature time-domain representations of the phase data from respective instantaneous phase signals constructed from the quantized received acoustic echo signals.

13. The machine-implemented method of claim 12, wherein, Aggregating the phase data includes quantizing the in-phase and quadrature time-domain representations of the phase data.

14. The machine-implemented method of claim 1, wherein, The segment construction includes allocating a phase difference of 2π radians between a time index of the quantized representation corresponding to a first rising edge and a later time index of the quantized representation corresponding to a next rising edge to define a slope of a segment.

15. The machine-implemented method of claim 1, wherein, The segment construction includes allocating a phase difference of π radians between a time index of the quantized representation corresponding to a first rising edge and a later time index of the quantized representation corresponding to a first falling edge to define a slope of a segment.

16. The machine-implemented method of claim 15, wherein, The segment construction includes allocating another phase difference of π radians between the time index of the quantized representation corresponding to the first falling edge and a later time index of the quantized representation corresponding to a second rising edge to define a slope of another segment.

17. A machine-implemented method for acoustic evaluation of a target, the method comprising: generating respective acoustic transmission events via selected transmit electroacoustic transducers of a plurality of electroacoustic transducers; receiving respective acoustic echo signals from other receive electroacoustic transducers of the plurality of electroacoustic transducers in response to the respective acoustic transmission events, the receiving including: one-bit quantizing the respective acoustic echo signals to provide a binarized representation of the received acoustic echo signals; generating a representation of the received acoustic echo signals; and constructing a time-domain representation of an instantaneous phase signal from the representation of at least one respective quantized acoustic echo signal, wherein the representation of the quantized received acoustic echo signals includes data indicative of time indices of edge transitions in the binarized representation of the received acoustic echo signals, wherein the time-domain representation of the instantaneous phase signal includes a segment construction, and wherein slopes of segments in the segment construction are established at least in part by determining durations between adjacent transitions of the quantized representation of the acoustic echo signals.

18. The machine-implemented method of claim 17, wherein, The one-bit quantizing the respective acoustic echo signals to provide a binarized representation includes detecting portions of the time-domain echo signals that exceed a specified signal amplitude threshold.

19. The machine-implemented method of claim 17, comprising: The constructing a time-domain representation of an instantaneous phase signal corresponding to the respective quantized received acoustic echo signals.

20. The machine-implemented method of any one of claims 17 to 19, comprising: transmitting the representation of the respective acoustic echo signals to another device for aggregating phase data corresponding to the received echo signals; and wherein the method includes generating at least one of an A-scan time series, a pixel value corresponding to a specified spatial location of the target, or a voxel value corresponding to the specified spatial location of the target.

21. The machine-implemented method of claim 20, wherein, The transmitting includes wirelessly transmitting the quantized representation of the respective acoustic echo signals.

22. An apparatus for acoustic evaluation of a target, the apparatus comprising: drive circuitry to generate respective acoustic transmission events via selected transmit electroacoustic transducers of a plurality of electroacoustic transducers; receiver circuitry comprising a coherent receiver topology to provide in-phase and quadrature representations of respective acoustic echo signals from other receiving electro-acoustic transducers of the plurality of electro-acoustic transducers; analog-to-digital conversion circuitry to digitize the respective acoustic echo signals, including single-bit quantization of respective received acoustic echo signals to provide a binary representation of the received acoustic echo signals; and processor circuitry to construct a time-domain representation of an instantaneous phase signal from the binary representation of at least one respective quantized acoustic echo signal, and to aggregate phase data corresponding to digitized acoustic echo signals, wherein the digitized acoustic echo signals comprise data indicative of time indices of edge transitions in the binary representation of the received acoustic echo signals, wherein the time-domain representation of the instantaneous phase signal comprises piecewise construction, and wherein slopes of segments in the piecewise construction are established at least in part by determining durations between adjacent transitions of the quantized representation of the acoustic echo signal.

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