Example displacement data files
One example displacement data file in each of the five compatible formats is available in this dedicated Dropbox folder.
Inside, the dropbox folder should look like this:
Each of the example files contains the same dataset, simply in different formats.
The example dataset is a full matrix captured from a 1D, periodic array with the following array parameters:
- Number of array elements
$n$ :$105$ - Number of displacement measurements per A-scan
$m$ :$1000$ - Array pitch (centre-to-centre spacing between elements):
$0.25$ mm
The array was formed on the surface of the following sample:
The sample was made of tungsten, for which the following elastic wave speeds may be taken:
$c_\mathrm{L}=5182\mathrm{ms^{-1}}$ $c_\mathrm{T}=2870\mathrm{ms^{-1}}$ $c_\mathrm{LSAW}=5182\mathrm{ms^{-1}}$
The time basis for each A-scan begins at -1 $\mu$s, and ends at 18.98 $\mu$s.
The displacement measurements recorded inside each of the files are not in units of nanometres, but volts output from a laser interferometer. These can be converted from V to nm by multiplying by a scalar conversion factor of 10 nm per volt (this can be performed in Chorus during the import).
The displacement measurements feature a non-zero DC offset, which should be removed by selecting the 'detrend' option in the Chorus import dialog.
To create TFM images using this dataset, the elastic wave speeds for tungsten given above may be used.
An imaging grid with a width of 30mm in the
