Data processing and -visualisation of NDT-data sets

Division VIII.2, Non-destructive Damage Assessment and Environmental Testing Methods, is deeply involved in developing techniques for data processing and data visualisation.

With the impulse echo methods like radar or ultrasonic echo 2D data sets are measured along lines on the surface of test specimens. These 2D data sets can be processed into 3D data sets.
The interpretability of data, gained from different transducers with different opening angles can be enhanced by reconstruction using the Synthetic Aperture Focusing Technique (SAFT). This reconstruction technique creates 3D data sets where the reflectors are focussed in their true positions and the signal to noise ratio is improved. For the determination of the depth or the lateral position of the reflectors any slice of the 3D data sets can be extracted independently from the pre-processing. Projections of different slices simplify the interpretation. Animated images of consecutive slices or 3D-movies provide a descriptive insight into the test specimen.

Visualisation of reconstructed data, taken at a concrete test specimen (2.0 m x 1.5 m x 0.5 m). Four radar data sets and one ultrasonic data set were used (enlarged picture).

• Animation

The main objective of the data fusion is the improvement and simplification of the interpretation of measurement results. Therefore the complementary information of different NDT-data sets is superimposed and compressed in a single fusion data set with the aid of simple mathematic algorithms. Raw data as well as pre-processed data (like SAFT reconstructed data sets) can be fused. The combination of raw data sets, however can lead to misinterpretation, and it is therefore more favourable to use reconstructed data sets for the fusion.

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