Time Corrected Gain (TCG) for TFM in GEKKO

Frédéric Reverdy

Senior Application and Products Engineer

We use a 5L64 linear phased-array probe with a L0 wedge over 4 side-drilled holes (SDH). We define a 35 x 50 mm TFM zone shown in red over the picture of the mockup. The number of pixels is 200 x 285 leading to a pixel size of lambda/7, which is small enough to avoid any problem of under sampling. We display, on the right, the TFM images with (bottom) and without TCG (top). We also display the associated echodynamic curves along the Z-axis . The echodynamic along Z displays the maximum for each row, it is really practical to see the amplitude of the 4 holes quickly. We can see, in the top echodynamic, that when we don't apply the TCG the variation in amplitude between the maximum and minimum holes is about 6 dB. The TCG is then calculated on GEKKO by moving the probe over the four holes to record the amplitude for each of the hole along all columns of the TFM. This way the TCG compensates not only for all depths but also for all angles. We can see, in the bottom echodynamic, that the amplitude of the 4 holes is now the same at 80%. GEKKO offers now a way to calibrate the TFM. Available in the next software update.

#Gekko #TFM #TCG #M2M