IMPROVEMENT OF CONSPICUITY BY FUSION OF PULSE-ECHO DATA

Abstract: Ultrasonic nondestructive testing based on pulse-echo measurements cannot detect faults if there is no reflected energy. Faults that are hidden behind an obstacle (for instance, another fault), or faults angled along the direction of beam propagation reflect negligible energy and will be difficult to detect. Thus, for a thorough examination of 3-D structures, pulse-echo data is collected from the same location using three different incident angles using different wedges attached to the acoustic probe. Typically, the data from the three wedges, for instance, 0-, 45- and 60-degree wedges, are simultaneously collected on three separate channels. The inspector then evaluates the data from all three channels. In this paper, we present a data fusion approach that strategically “fuses ” all collected data to improve conspicuity of faults. Obvious advantages of the proposed data fusion are: (1) to visualize occluded faults (if at least one of channel “sees ” the fault), (2) the signal-to-noise ratio (SNR) is expected to improve by the factor N where is the number of channels, even by performing a simple averaging as data fusion, and (3) the inspector only has to view one fused data set rather than all the collected data sets. N In particular, the data fusion is applied to the problem of 3-D rendering techniques, namely volume rendering (VR), surface rendering (SR) and maximum intensity projection (MIP). The exact fusion algorithm will differ fo