Total Focusing Method (TFM)

How does TFM Work?

The Total Focusing Method (TFM) is an ultrasonic array technique which is used to synthetically focus at every point of a region of interest.

Details

1st Step: Data Collection with Full Matrix Capture (FMC)

  • Full Matrix Capture (FMC) is another way of collecting phased array data
  • This technique doesn’t require any knowledge of the piece to be inspected (nor shape, nor velocities)
  • Each element is just activated (shot) one by one
  • All the elements in reception are recorded and thus a Matrix of signal is stored in order to be processed

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2nd Step: Reconstruction: Total Focusing Method (TFM)

Main Advantages of TFM

  • Optimal focusing and spatial resolution everywhere
  • Direct imaging of a large area for one probe position
  • All reachable angles with the array simultaneously
  • Defect characterisation
  • Comprehensive imaging of defect
  • 3D imaging

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Comparison with Electronic Scanning

Electronic scanning

  • 8-element aperture
  • Focused along the defects in the middle
  • 57 shots

TFM

  • 64-element aperture
  • Focused everywhere
  • 64 shots

Electronic scanning
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TFM
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Comparison with Sector Scanning

Sectorial scanning

  • 64-element aperture
  • Focused along the defects in the middle
  • Sectorial between -55° and 55° with 110 shots

TFM

  • 64-element aperture
  • Focused everywhere
  • 64 shots

Sector scanning
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TFM
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