Synthetic Aperture Focusing Technique Imaging with PAUT and ToFD Data.
Tracks
NDT Methods
| Tuesday, October 22, 2024 |
| 4:00 PM - 4:30 PM |
| 207/208 - Technical Session |
Details
Over the past decade, advanced ultrasonic imaging techniques such as Full Matrix Capture/Total Focusing Method (FMC/TFM), Plane Wave Imaging (PWI) and Phase Coherence Imaging (PCI) have received considerable attention due to the fact that images rendered with these techniques are more readily interpretable than traditional ultrasonic inspection data, namely traditional Phased Array (PA) sector scans or Time of Flight Diffraction (ToFD). This improved imaging performance comes at the cost of reduced scan speeds, more sophisticated/costly hardware requirements and additional personnel training. Conventional Ultrasonic Testing (UT) scans can be re-processed by means of the Synthetic Aperture Focusing Technique (SAFT) in which the overlap in beam divergence is leveraged to render high resolution images from UT signals. SAFT can also be applied using PA hardware and probes, however, adoption of this approach has been limited, due primarily to the fact that PA-SAFT cannot be applied directly to PA scans as typically acquired (sectorial, linear or compound scans). Furthermore, PA-SAFT does not allow for indirect modes (corner modes, e.g. T-TT) to be rendered, making sizing of vertically oriented indications less accurate. To make PA-SAFT more generally useful, a new post-processing technique has been derived which makes it possible to render SAFT images from standard PA beamsets (focused or unfocused) and allows for rendering of arbitrary modes, similar to FMC/TFM. In addition, the technique can be applied to ToFD data (commonly acquired with PA scans) and the resulting SAFT images from PA and ToFD merged by summation or using the Delay Multiply and Sum (DMaS) algorithm. Where possible, pulse/echo signals acquired from the ToFD transducers may be processed via the modified SAFT algorithm and merged with the pitch/catch ToFD and PA-SAFT images. The performance of this general SAFT process is demonstrated on a variety of calibration targets and simulated weld flaws. In each case, results are directly compared with the un-processed PA and ToFD data as well FMC/TFM images acquired with the same setup. The SAFT images are found to be of similar quality (resolution) to the comparable FMC/TFM images with improvements in interpretability and through wall sizing accuracy observed when compared with the un-processed PA images, particularly when combined with the SAFT processed ToFD data.
Speaker
Mohammad Marvasti
NDT Applications Engineer
Synthetic Aperture Focusing Technique Imaging with PAUT and ToFD Data.
Presentation Description
Over the past decade, advanced ultrasonic imaging techniques such as Full Matrix Capture/Total Focusing Method (FMC/TFM), Plane Wave Imaging (PWI) and Phase Coherence Imaging (PCI) have received considerable attention due to the fact that images rendered with these techniques are more readily interpretable than traditional ultrasonic inspection data, namely traditional Phased Array (PA) sector scans or Time of Flight Diffraction (ToFD). This improved imaging performance comes at the cost of reduced scan speeds, more sophisticated/costly hardware requirements and additional personnel training. Conventional Ultrasonic Testing (UT) scans can be re-processed by means of the Synthetic Aperture Focusing Technique (SAFT) in which the overlap in beam divergence is leveraged to render high resolution images from UT signals. SAFT can also be applied using PA hardware and probes, however, adoption of this approach has been limited, due primarily to the fact that PA-SAFT cannot be applied directly to PA scans as typically acquired (sectorial, linear or compound scans). Furthermore, PA-SAFT does not allow for indirect modes (corner modes, e.g. T-TT) to be rendered, making sizing of vertically oriented indications less accurate. To make PA-SAFT more generally useful, a new post-processing technique has been derived which makes it possible to render SAFT images from standard PA beamsets (focused or unfocused) and allows for rendering of arbitrary modes, similar to FMC/TFM. In addition, the technique can be applied to ToFD data (commonly acquired with PA scans) and the resulting SAFT images from PA and ToFD merged by summation or using the Delay Multiply and Sum (DMaS) algorithm. Where possible, pulse/echo signals acquired from the ToFD transducers may be processed via the modified SAFT algorithm and merged with the pitch/catch ToFD and PA-SAFT images. The performance of this general SAFT process is demonstrated on a variety of calibration targets and simulated weld flaws. In each case, results are directly compared with the un-processed PA and ToFD data as well FMC/TFM images acquired with the same setup. The SAFT images are found to be of similar quality (resolution) to the comparable FMC/TFM images with improvements in interpretability and through wall sizing accuracy observed when compared with the un-processed PA images, particularly when combined with the SAFT processed ToFD data.
Biography
Mohammad is an NDT Applications Engineer with Acuren's Applications Development Group. He began his career at Eclipse Scientific (since acquired by Acuren) working on a high temperature phased array inspection system. Since that time, he has worked on deploying advanced ultrasonic inspection techniques for challenging inspections. He holds a Ph.D. from the University of Toronto and a CSWIP Phased Array Level II certification. Mohammad works closely with his colleague Jonathan Lesage to provide support to Acuren's Advanced Services divisions as well as consultation services for external clients.
