Automated scan data quality assessment in ultrasonic testing

A system comprising a computer readable storage device readable by the system, tangibly embodying a program having a set of instructions executable by the system to perform the following steps for detecting a sub-surface defect, the set of instructions comprising an instruction to receive scan data for a part from a transducer; an instruction to collect the scan data; an instruction to determine an indication in the scan data that indicates a distractor, wherein the indication is based on a learning phase module and an inference phase module that the processor uses to self-assess the indication; and an instruction to create a defect indication report.

BACKGROUND

The present disclosure is directed to the improved process for assessing the quality scan data for the automatic inspection of engine parts using immersion pulse-echo inspection technology.

Aerospace engine components, may incur defects or imperfections during the manufacturing process. Non-destructive testing (NDT) inspections are performed during different stages of the manufacturing process to identify defective parts. Inspection methods include, but are not limited to, visual inspection, X-Ray, thermography, and ultrasonic testing. It is particularly difficult to inspect components that have an internal structure using only external observations. Forms of flaws such as porosity and inclusions in metallic parts are particularly difficult to detect. These types of defects can grow and damage the part in service. Such internal defects are often detected by some form of excitation of the structure (ultrasonic, thermoacoustic, and the like), sensing of the excitation, and manual interpretation of the sensor signals, see for exampleFIG.1. This manual inspection process is tedious, time consuming, and error prone.

What is needed is a mechanism that can identify scan data distractors with high accuracy, thus being successful at classifying indications as actual part defects.

SUMMARY

In accordance with the present disclosure, there is provided a system for detecting a sub-surface defect comprising a transducer fluidly coupled to a part located in a tank containing a liquid configured to transmit ultrasonic energy, the transducer configured to scan the part to create scan data of the scanned part; a pulser/receiver coupled to the transducer configured to receive and transmit the scan data; a processor coupled to the pulser/receiver, the processor configured to communicate with the pulser/receiver and collect the scan data; and the processor configured to detect the sub-surface defect; a tangible, non-transitory memory configured to communicate with the processor, the tangible, non-transitory memory having instructions stored therein that, in response to execution by the processor, cause the processor to perform operations comprising receiving, by the processor, the scan data for the part from the transducer; collecting, by the processor, the scan data; determining, by the processor, a defect indication in the scan data that indicates a distractor, wherein the indication is based on a learning phase module and an inference phase module that the processor uses to self-assess the indication; and creating, by the processor, a defect indication report.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the scan comprises transmitting ultrasonic energy to the part and receiving the ultrasonic energy from the part.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the distractor comprises at least one of a bubble, a floater, a surface condition, or a defect.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the system further comprises determining, by the processor, a defect characteristic including at least one of a defect size, a defect location, and a defect type.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the system further comprises verifying, by the processor, that the indication is cleared and dimensioning the indication.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the system further comprises providing, by the processor, an A-scan pre-processing function utilizing the learning phase module and the inference phase module.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the system further comprises providing, by the processor, a disposition of one of an indication being a defect or an indication being a distractor.

In accordance with the present disclosure, there is provided a system comprising a computer readable storage device readable by the system, tangibly embodying a program having a set of instructions executable by the system to perform the following steps for detecting a sub-surface defect, the set of instructions comprising an instruction to receive scan data for a part from a transducer; an instruction to collect the scan data; an instruction to determine an indication in the scan data that indicates a distractor, wherein the indication is based on a learning phase module and an inference phase module that the processor uses to self-assess the indication; an instruction for automated decision making to take corrective action if the indication is a distractor; and an instruction to create a defect indication report.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the scan data is selected from at least one of C-scans and A-scans.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include determining the indication in the scan data utilizes a temporal ML model trained using previously and newly obtained A-scans in the learning phase module for classifying the distractor.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the step of determining an indication in the scan data that indicates a distractor is responsive to neural network-based approaches including sequence or LSTM auto encoders, and generative adversarial networks.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the system further comprises an instruction to classify each the distractor indication; and an instruction to determine if a rescan is required.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the system further comprises an instruction to alert an inspector responsive to the nature and severity of the distractor; or an instruction to request a rescan of the part.

In accordance with the present disclosure, there is provided a process for detecting a sub-surface defect by use of a system including a transducer fluidly coupled to a part located in a tank containing a liquid configured to transmit ultrasonic energy, the transducer configured to scan the part to create scan data of the scanned part; a pulser/receiver coupled to the transducer configured to receive and transmit the scan data; a processor coupled to the pulser/receiver, the processor configured to communicate with the pulser/receiver and collect the scan data; and the processor configured to detect the sub-surface defect, a tangible, non-transitory memory configured to communicate with the processor, the tangible, non-transitory memory having instructions stored therein that, in response to execution by the processor, cause the processor to perform operations comprising receiving, by the processor, the scan data for the part from the transducer, wherein the scan data comprises at least one of C-scan data and A-scan data; collecting, by the processor, the scan data; determining, by the processor, a defect indication in the scan data that indicates a distractor, wherein the indication is based on a learning phase module and an inference phase module that the processor uses to self-assess the defect indication; and creating, by the processor, a defect indication report.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the process further comprising classifying by the processor, each the distractor indication; and determining by the processor, if a rescan is required.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the process further comprising analyzing, by the processor, an A-scan associated with the indication as additional scan data to identify quality issues in the scan data.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the process further comprising alerting by the processor, an inspector responsive to the nature and severity of the distractor; or requesting by the processor, a rescan of the part.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively includethe step of determining an indication in the scan data that indicates a distractor is responsive to data augmentation techniques comprises at least one of shifting, scaling, locally added noise, and neural network-based approaches including sequence or LSTM auto encoders, and generative adversarial networks.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include determining the indication in the scan data utilizes a temporal ML model trained using previously and newly obtained A-scans in the learning phase module for classifying the distractor.

A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the process further comprising providing, by the processor, a disposition of one of an indication being a defect or an indication being a distractor.

Other details of the process are set forth in the following detailed description and the accompanying drawings wherein like reference numerals depict like elements.

DETAILED DESCRIPTION

Referring now toFIG.2, the exemplary ultrasonic testing (UT) inspection system10is shown. The UT inspection system10includes several functional units, such as a pulser/receiver12, transducer14, and display devices16. A pulser/receiver12is an electronic device that can produce high voltage electrical pulses18. Driven by the pulser12, the transducer14generates high frequency ultrasonic energy (sound energy)20. The sound energy20is introduced and propagates in the form of waves through a liquid coupling medium materials24in the UT tank22, such as water, and the part being inspected26, like an engine disk. When there is a discontinuity28in the part26, such as a crack, located in the wave path, a portion of the energy20will be reflected back from the discontinuity (indication)28surface. The transducer14can detect the reflected energy wave. The reflected wave signal is transformed into scan data30relayed in the form of an electrical signal18by the transducer14and relayed to a first processor32and displayed on a screen16(Computer1inFIG.2). A second processor34(Computer2inFIG.2) is configured to automatically analyze the scan data30to distinguish between actual part defects and spurious indications of defects.

A more detailed schematic of the interactions between first processor32and the UT tank22is shown inFIG.3. The first processor32is responsible for multiple functions. One of those functions includes sending scan plan information36to a robot controller38. The first processor32can communicate with a motor controller40. The motor controller40is configured to operate a motor42to rotate a turntable44supporting the inspected part26. The first processor32can also receive scan signal data30from the pulser/receiver12received from the transducer14coupled to a robot46to be displayed for review by an inspector48.

The scan plan36contains instructions50for moving a robotic arm52and positioning the transducer14around the inspected part26for collection of scan data30. The data30can be collected by scanning every surface54of the part26until the totality of surfaces54of the part26that cover the entirety of the part26volume have been scanned. In order to generate a scan plan36, the inspector48configures the scan by setting parameters56in a UT tank vendor software58installed on the first processor32. The values of such parameters56depend on the inspected part26; some parameters56and their representative values include water path length, that is, the distance between the tip of the transducer14and the inspected part26of for example, 100 mm.

The pulser/receiver12produces outgoing electrical pulses18to the transducer14and receives/amplifies returning pulses18from the transducer14. The robotic arm52aides in the translation (spatial coordinates) and angulation (tilting) of the transducer14according to the scan plan36. A single transducer14generates and receives sound wave signals20that traverse the liquid medium24and the inspected part26.

One of the main uses of the UT inspection system10is for detecting and evaluating flaws or defects in physical parts26, such as turbine components of gas turbine engines. A defect can be defined as a region of a material or a structure that has different physical properties from its neighborhood (causing a discontinuity in that region), and those differences in properties are not intended during manufacturing. Defects can occur during manufacturing or if the physical properties are altered over time. Some examples of defects detected by ultra-sonic inspection are inclusions (e.g., non-metallic, metallic, reactive inclusions), or cracks. An indication is how those defects show up in the signals coming out from the immersion pulse-echo ultrasonic system. Not all indications detected are defects because there might be false positives, but the premise from the inspection method is that all defects conforming to NDT specifications are detected as indications. Defect identification is performed by scanning parts26by pulser/receiver12, transducer14, and display devices32,34. Ultrasonic data30of the scanned part26can be formatted into three presentations: A-scan, B-scan, and C-scan. The A-scan presentation is a one dimension, 1-D plot that displays the amount of received ultrasonic energy (vertical axis) as a function of time (horizontal axis). The B-scan presentation is a cross-sectional, two dimension, 2-D profile of the time-of-flight (time travel or depth) of the sound energy in the vertical axis and the linear position of the transducer14in the horizontal axis. Lastly, the C-scan presentation is also a 2-D plot that captures a plan-type view of the location and size of the part; plots for either relative signal amplitude or time-of-flight may be generated. Multiple presentation scans can be used together for more accurate determinations of the condition of the part26.

Absence of indications28in A/B/C-scans represents a clean part26without defect. The existence of indications28can be due to two main reasons: 1) part defects or 2) distractors. Distractors58is a general term corresponding to any artifact which appears as a false indication/defect and includes for example, floaters (debris that cause interruption of the sound beam), electrical noise (interfering electrical currents), and surface flare (resonance between wave length of sound beam and the profile of the machining grooves). Other factors such as transducer noise, material noise, and miss alignment between transducer and part, could also impact the ultrasonic data quality and generate false alarms. Depending on the nature and degree of distractors58, a part26rescan may be required. Nevertheless, manual analyses of scan data, and especially across different presentations, are tedious, time-consuming, imprecise, and error prone. Disclosed herein is a mechanism that can identify these distractors58with high accuracy, to be used in classifying indications as actual part defects. A system and method for assessing the quality of UT scan data, from detecting and classifying distractors to deciding the appropriate course of action to eliminate them is disclosed.

Referring also toFIG.4, in an exemplary embodiment of a process map is shown. The process60includes the use of a processor62which can include one or more processors62(e.g., computer systems having a central processing unit and memory) for recording, processing and storing the data received. The processor62may include a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof.

The processor62can operate within the process60to assess the quality of UT scan data by leveraging computer vision techniques and subject matter expert criteria applied to C-scan presentations coupled with temporal machine learning (ML) models for pattern recognition of associated A-scan presentations.

The process60begins with the collection of scan data30particularly both amplitude and time-of-flight C-scans at step64. The process60at66, includes use of the processor62within a module I68that processes any indication in the scan data30that adheres to a subject-matter expert (SME)-defined criteria for indications28(for example, amplitude values above evaluation threshold). Module I68is the main distractor classifier to discriminate indications28into either distractors58with the correct label for example, bubble, floater, surface condition, or actual defects that are then passed to a dimensioning module II70to determine defect characteristics such as, the defect size, location, and type at step72. Module II70serves a dual purpose of verification that the actions performed as output of the decision model in Module I68have cleared out the indication28and also allows for dimensioning of actual defect indications28based on such factors as size, location, and type of defect, for defect indication58reporting purposes at84as shown inFIG.4.

Referring also toFIG.5, the schematic workflow of the process60shows details utilized to detect those distractors58in module I68. Module I68includes instructions for the processor62to begin with the extraction of A-scan data72for the pixel with highest signal amplitude value in each of the detected indications58. The next steps within module I68include A-scan pre-processing74which can support a hybrid approach to perform a learning phase at a module I.B76(for example, build predictive ML models), and run an inference phase at module I.C78(for example, predict the class of each distraction indication58) as illustrated inFIG.5.

During the inference phase78, the processor62utilizes a temporal ML model that had been trained using previously and newly obtained A-scans in the learning phase76is used to classify the nature of the distraction indication58(for example, bubbles, floaters, electrical noise, and surface flare). Such models can be variants of deep recurrent neural networks, including long short-term memory (LSTM) and gated recurrent network (GRU). Prior to feeding A-scans to the processor62, each A-scan signal must be pre-processed (for example, by resampling) so that all data samples in the network input layer have the similar shape.

The model learning phase in module I.B76is aided by data augmentation techniques to enrich a training dataset80and make the ML model robust by reducing the possibility of overfitting. Such techniques include shifting, scaling, locally added noise, and neural network-based approaches (for example, sequence or LSTM auto encoders, and generative adversarial networks). Once a final temporal ML model is obtained and new UT scan data are available, inference can be performed in the module I.C78, where each distraction indication58is classified and a determination is made whether a rescan is required. Finally, in module I.D82, depending on the nature and severity of the distractor indication58, an automated decision is made to eliminate source of distractor in the ultrasonic data, for instance, to automatically remove bubble using a robotic actuator, initiate a calibration procedure to align transducer orientation w.r.t. to scanned part, request partial/full rescan, and/or alert the UT tank operator/inspector48with details about distractor, who can then take appropriate corrective action e.g. remove bubble/floaters or machine the part surface to remove profile of the machining grooves and eliminate surface flare.

A technical advantage of the process described is a mechanism utilized for an increased yield in part inspections with minimal human intervention.

Another technical advantage of the disclosed process can include leveraging two scan presentations, subject matter expertise, and analytics for the classification of distraction indicators.

Another technical advantage of the disclosed process can include using classification of distractors to take more informed trouble shooting actions to eliminate scan data quality issues.

There has been provided a process. While the process has been described in the context of specific embodiments thereof, other unforeseen alternatives, modifications, and variations may become apparent to those skilled in the art having read the foregoing description. Accordingly, it is intended to embrace those alternatives, modifications, and variations which fall within the broad scope of the appended claims.