The most evident benefit of using the TFM envelope is to discard the amplitude oscillations resulting from the use of naturally oscillating acoustic wave A-scans as the basic data set. Free of the oscillation artifacts, the amplitude becomes more continuous, and the sizing easier. Also, the TFM envelope image can be obtained at a higher acquisition rate than the standard oscillating TFM while maintaining the same amplitude fidelity (AF) value. The below examples show high-temperature hydrogen attack (HTHA) defects with the envelope off (top) and on (bottom). When the TFM envelope feature is on, the grid resolution can be coarser, yet the amplitude fidelity remains under 2 dB (the standard tolerance) and the acquisition rate increases. In comparing these two images, defect echoes can be more easily identified with the envelope activated. Because it is more robust against oscillations, the TFM envelope image can help ease flaw interpretation and amplitude-based sizing.