AVASA: A new paradigm in Phased Array Ultrasound Technique
Tracks
NDT Methods
| Tuesday, October 22, 2024 |
| 3:30 PM - 4:00 PM |
| 207/208 - Technical Session |
Details
Traditional phased array ultrasound technique (PAUT) uses active focusing of a set of elements to achieve beam forming and imjproved imaging capabilities. The more recent approach involving FMC/TFM PAUT improves this method using synthetic reconstruction approaches. In this presentation, we present a novel hybrid approach that uses both active and synthetic focusing approaches using a set of Arbitrary Virtual Array of Source Aperture (AVASA) PAUT method. Some of the key advantages of this AVASA approach includes (a) imaging of deeper defects (b) Lower time for inspection, (c) improved imaging of defect shapes and sizes, and (d) improved imaging of defects in hard to reach regions. Algorithms such as PCI can be subsequently utilized to further improve image quality. This is achieved using the currently available PAUT probes and instruments available in the market, with only the focal laws and reconstruction algorithm that are to be customized for the AVASA inspection.
AVASA uses a novel algorithm where the array elements to transmit the ultrasound wave with pre-calculated delay laws to create the beamforming to focus at arbitrary virtual source locations placed below the physical transducer, This is the active focusing part of the AVASA algorithm where each source introduces significantly higher amplitude of waves into the material, hence allowing for deeper penetration and imaging. Once the desired set of virtual sources are formed within the material, the synthetic algorithms of FMC/TFM can be used to image the regions of the material. The AVASA further is capable of using virtual sources in any configurations and need not be periodic or linear. This will reduce the well known periodicity artifacts and also allow for improved imaging using multiple angles to the defect. The virtual source parameters, such as the number of virtual sources, corresponding active aperture position in the transducer, and virtual source locations inside the material, are determined using the Poisson point process (PPP) function. Each virtual source is located below the transducer and within the area formed by the active aperture width to the near field distance. The images obtained using AVASA are qualitatively compared with FMC/TFM using an evaluation index, such as SNR,API, defect size, and image processing time, and found to be significantly better. AVASA PAUT was found to be faster with improved image quality and could be implemented for various industries to inspect critical structures. Two applications will be used to illustrate this approach, one on weld inspection and another on small inclusion detection in large castings.
Speaker
Krishnan Balasubramanian
Professor
Indian Institute Of Technology Madras
AVASA: A new paradigm in Phased Array Ultrasound Technique
Presentation Description
Traditional phased array ultrasound technique (PAUT) uses active focusing of a set of elements to achieve beam forming and imjproved imaging capabilities. The more recent approach involving FMC/TFM PAUT improves this method using synthetic reconstruction approaches. In this presentation, we present a novel hybrid approach that uses both active and synthetic focusing approaches using a set of Arbitrary Virtual Array of Source Aperture (AVASA) PAUT method. Some of the key advantages of this AVASA approach includes (a) imaging of deeper defects (b) Lower time for inspection, (c) improved imaging of defect shapes and sizes, and (d) improved imaging of defects in hard to reach regions. Algorithms such as PCI can be subsequently utilized to further improve image quality. This is achieved using the currently available PAUT probes and instruments available in the market, with only the focal laws and reconstruction algorithm that are to be customized for the AVASA inspection.
AVASA uses a novel algorithm where the array elements to transmit the ultrasound wave with pre-calculated delay laws to create the beamforming to focus at arbitrary virtual source locations placed below the physical transducer, This is the active focusing part of the AVASA algorithm where each source introduces significantly higher amplitude of waves into the material, hence allowing for deeper penetration and imaging. Once the desired set of virtual sources are formed within the material, the synthetic algorithms of FMC/TFM can be used to image the regions of the material. The AVASA further is capable of using virtual sources in any configurations and need not be periodic or linear. This will reduce the well known periodicity artifacts and also allow for improved imaging using multiple angles to the defect. The virtual source parameters, such as the number of virtual sources, corresponding active aperture position in the transducer, and virtual source locations inside the material, are determined using the Poisson point process (PPP) function. Each virtual source is located below the transducer and within the area formed by the active aperture width to the near field distance. The images obtained using AVASA are qualitatively compared with FMC/TFM using an evaluation index, such as SNR,API, defect size, and image processing time, and found to be significantly better. AVASA PAUT was found to be faster with improved image quality and could be implemented for various industries to inspect critical structures. Two applications will be used to illustrate this approach, one on weld inspection and another on small inclusion detection in large castings.
AVASA uses a novel algorithm where the array elements to transmit the ultrasound wave with pre-calculated delay laws to create the beamforming to focus at arbitrary virtual source locations placed below the physical transducer, This is the active focusing part of the AVASA algorithm where each source introduces significantly higher amplitude of waves into the material, hence allowing for deeper penetration and imaging. Once the desired set of virtual sources are formed within the material, the synthetic algorithms of FMC/TFM can be used to image the regions of the material. The AVASA further is capable of using virtual sources in any configurations and need not be periodic or linear. This will reduce the well known periodicity artifacts and also allow for improved imaging using multiple angles to the defect. The virtual source parameters, such as the number of virtual sources, corresponding active aperture position in the transducer, and virtual source locations inside the material, are determined using the Poisson point process (PPP) function. Each virtual source is located below the transducer and within the area formed by the active aperture width to the near field distance. The images obtained using AVASA are qualitatively compared with FMC/TFM using an evaluation index, such as SNR,API, defect size, and image processing time, and found to be significantly better. AVASA PAUT was found to be faster with improved image quality and could be implemented for various industries to inspect critical structures. Two applications will be used to illustrate this approach, one on weld inspection and another on small inclusion detection in large castings.
Biography
Prof. Krishnan Balasubramaniam is currently the Institute Professor at the Indian Institute of Technology Madras and serves as the Head of the Centre for Nondestructive Evaluation which he founded in 2001. He is also the current PRESIDENT of ISNT. He has over 530 technical publications (including 290 refereed journal papers), 46 patents filings and has directed 29 PHD student dissertations and 55 MS student theses. He has been bestowed with the prestigious Roy Sharpe Prize by BiNDT in 2012. He has founded several startups including Dhvani Research, Playns Technologies, Detect Technologies, Maximl Labs, Xyma Analytics and Solinas Integrity.
