Changes between Version 49 and Version 50 of Tutorial/ParticleImageVelocimetry
- Timestamp:
- Mar 24, 2015, 10:53:51 AM (10 years ago)
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Tutorial/ParticleImageVelocimetry
v49 v50 12 12 The PIV computation is accessed from '''uvmat''' by the upper bar command '''[Run/PIV]''', or from '''series''' by selecting the function '''civ_series'''. The name 'CIV' means '''C'''orrelation '''I'''maging '''V'''elocity to stress that the method relies on image correlation, which evaluates the displacement of image textures, not necessarily from particles. Note that an older GUI ''''civ' '''is also available, but it is obsolete and not used here. 13 13 14 A new GUI '''civ_input''' now appears. In the menu '''[!ListCompareMode]''', keep the default option 'PIV'. Keep the default option 'Di=0|1' for the image pair (menu tag '''[!ListPairCiv1]''') and the default parameters in the frame '''CIV1'''. Press '''[OK]''' so the GUI '''civ_input''' desappears. Then press '''[RUN] ''' in the GUI''' series''' to run the calculation. The button '''[RUN]''' is then colored to yellow until the computation is finished.14 A new GUI '''civ_input''' now appears. In the menu '''[!ListCompareMode]''', keep the default option 'PIV'. Keep the default option 'Di=0|1' for the image pair (menu tag '''[!ListPairCiv1]''') and the default parameters in the frame '''CIV1'''. Press '''[OK]''' so the GUI '''civ_input''' desappears. Then change '''i_last''' to 2 and press '''[RUN] ''' in the GUI''' series''' to run the calculation. The button '''[RUN]''' is then colored to yellow until the computation is finished. 15 15 16 16 The operation produces a file with format netcdf, named with extension '.nc', in a folder called 'Images.civ'. This can be viewed by pressing '''[STATUS] '''in the GUI '''series''', which displays the result file 'frame_1-2.nc'. The index string '_1-2' indicates that it results from images 1 and 2. Select the file name and press '''[OPEN]''' to open it directly with '''uvmat''', or use the browser of '''uvmat'''. … … 89 89 Then the mask itself is produced by the menu bar command '''[!Tools/Make mask]'''. The corresponding image is then displayed and stored by default in the directory of the initial image. Note that if several mask polygons have been initially created, as listed in '''[!ListObject]''' (bottom right of the GUI uvmat), they will be merged as dark regions in the resulting mask (useful in case of multiple ’holes’). 90 90 91 The mask image can be seen as a mask by selecting '''[view_mask]''' at the upper left of the GUI '''uvmat''' . For checking purpose, it can be also opened by the browser of '''uvmat''' like any image. In the GUI '''civ_input''', the mask is introduced by the selecting the green check box '''[Mask]'''. Vectors under the mask are not calculated in the resulting velocity data.91 The mask image can be seen as a mask by selecting '''[view_mask]''' at the upper left of the GUI '''uvmat''' next to '''[REFRESH]'''. For checking purpose, it can be also opened by the browser of '''uvmat''' like any image. In the GUI '''civ_input''', the mask is introduced by the selecting the green check box '''[Mask]'''. Vectors under the mask are not calculated in the resulting velocity data. 92 92 93 93 [[Image(Tutorial5 - CIV with mask.png)]]