wiki:Tutorial/AdvancedParticleImagingVelocimetry2

Version 5 (modified by sommeria, 11 years ago) (diff)

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This is an example using more advanced tools than the examples .... and .... Image pre_processing and merging of mutiple fields. Open the example UVMAT_DEMO_FILES/EX07_convection .

calibration

mark corners

mask

sub_background

first PIV

making two masks

The parietal jet requires a very good resolution, particularly among x. To limitate PIV to this jet, let us create a specific mask. Open the previously created contour polygon contour_mask.xml in uvmat by the menu bar Tools/Projection object/browse.... Check the box edit (tag [CheckEditObject]) in the frame Object of uvmat (right hand side) to allow editing of the polygon. then replace the lower x bound 0 by 52. Then create the corresponding mask by Tools/make mask, save it with name Dalsa1.mask/mask_plume.png. Similarly create a mask for the bulk Dalsa1.mask/mask_bulk.png, with bounds in x [0 55].

PIV on the parietal plume

Choose the following parameters:

  • pair j=1-2 for Civ1 and Civ2 : it minimises the time interval which is needed to capture the large velocity in the plume.
  • CorrBox? x,y=(5 31) which optimizes the resolution in x (5 pixels)
  • Search x, y=(25 55) which allows for a larger velocity component along y .
  • auto-grid Dx=2, Dy=10, consistent with CoorBox? (about half the box size).
  • Mask selected, with name .../Dalsa1.mask/mask_plume.png .
  • For Civ2, same parameters CorrBox?, auto-grid and Mask.
  • For patch and Fix, default parameters.

PIV on the interior

Select the pair j=1-3 to deal with the small velocities (considering that the parietal plume has been masked). Then use the default parameters.

merging data on a common grid

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