Changes between Version 49 and Version 50 of Tutorial/AdvancedParticleImagingVelocimetry2


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Timestamp:
Jan 23, 2015, 2:07:39 PM (6 years ago)
Author:
vaillant1p
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  • Tutorial/AdvancedParticleImagingVelocimetry2

    v49 v50  
    55
    66= Calibration =
    7 Perform the geometric calibration by marking the four box corners with the mouse, as described in [wiki:Tutorial/GeometricCalibration Tutorial: geometric calibration], section 'calibration with reference points'. Alternatively, you can skip this operation by using the reference file Dalsa1.ref.xml provided, removing the extension '.ref' to make it active.
     7Perform the geometric calibration by marking the four box corners with the mouse, as described in [wiki:Tutorial/GeometricCalibration Tutorial: geometric calibration], section 'calibration with reference points'. Alternatively, you can skip this operation by using the reference file 'Dalsa1.ref.xml' provided, removing the extension '.ref' to make it active.
    88
    99= Mask =
    10 Open the original image with '''uvmat''', selecting the transform option 'phys'. Create a mask polygon by the menu bar command '''Projection object/mask_polygon'''. Set the option 'mask_outside' and introduce the coordinates of the four corners in '''Coord''' (like for geometry calib). Plot the polygon, save it as 'contour_mask.xml' then create the corresponding mask by '''Tools/make mask'''. The default name is 'mask_1.png' in the subfolder Dalsa1.mask.
     10Open the original image with '''uvmat''', selecting the transform option 'phys'. Create a mask polygon by the menu bar command '''[Projection object/mask_polygon]'''. Set the option 'mask_outside' and introduce the coordinates of the four corners in '''[Coord]''' (like for '''geometry_calib'''). Plot the polygon, save it as 'contour_mask.xml' then create the corresponding mask by '''[Tools/make mask]'''. The default name is 'mask_1.png' in the subfolder 'Dalsa1.mask'.
    1111
    1212= Sub_background =
    13 We observe parasitic light rays on the images which correspond to fixed features, leading possibly to spurious velocity vectors equal to 0. To eliminate those we use '''sub_background'''.  In the GUI uvmat, select '''Run/field series'''. Then select the program 'sub_background'. This function is not provided in the default menu, so you need to use the last menu option 'more...', and select the function in the sub-folder 'series/' of the package uvmat. This option is then preserved in the menu for later use.  Then run '''sub_background''' over the whole index range in i and j, using the default parameters. Answer Yes to the question 'apply levels', which will conveniently rescale the image brightness after background removal.
     13We observe parasitic light rays on the images which correspond to fixed features, leading possibly to spurious velocity vectors equal to 0. To eliminate those we use '''sub_background'''.  In the GUI '''uvmat''', select '''[Run/field series]'''. Then select the program 'sub_background'. This function is not provided in the default menu, so you need to use the last menu option 'more...', and select the function in the sub-folder 'series/' of the package uvmat. This option is then preserved in the menu for later use.  Then run '''sub_background''' over the whole index range in i and j, using the default parameters. Answer '''[Yes]''' to the question 'apply levels', which will conveniently rescale the image brightness after background removal.
    1414
    1515= First PIV =
    16 Do a PIV on the whole image series, optained with '''sub_background''' (stored in a ''Dalsa1.sback'' subfolder), selecting all the options from Civ1 to Patch2 (see [wiki:Tutorial/ParticleImageVelocimetry Tutorial: Particle Image Velocimetry] for an introduction).
     16Do a PIV on the whole image series, optained with '''sub_background''' (stored in a 'Dalsa1.sback' subfolder), selecting all the options from Civ1 to Patch2 (see [wiki:Tutorial/ParticleImageVelocimetry Tutorial: Particle Image Velocimetry] for an introduction).
    1717
    1818Choose the pair 'j=1-2' which provides the smaller time interval (100 ms), a good choice to capture correlations in a first try (although higher precision can be obtained with a larger time interval if the correlation is still of good quality).
     
    2323
    2424= Making two masks =
    25 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 '''Projection object/browse...'''. Check the box '''edit''' (tag '''[!CheckEditObject]''') in the frame '''Object''' of '''uvmat''' (left hand side) to allow editing of the polygon then replace the lower ''x'' bound 0 by 52. Select the '''[SAVE]''' button to save it as a .xml figure. Create the corresponding mask by '''Tools/make mask''', save it with name ''Dalsa1.mask/mask_plume.png''. Similarly create a mask for the bulk, saving it as a .xml figure and with '''Tools/make mask''' as ''Dalsa1.mask/mask_bulk.png'', with bounds in ''x'' [0 55].
     25The 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 '''[Projection object/browse...]'''. Check the box '''edit''' (tag '''[!CheckEditObject]''') in the frame '''[Object]''' of '''uvmat''' (left hand side) to allow editing of the polygon then replace the lower ''x'' bound 0 by 52. Select the '''[SAVE]''' button to save it as a .xml figure. Create the corresponding mask by '''[Tools/make mask]''', save it with name 'Dalsa1.mask/mask_plume.png'. Similarly create a mask for the bulk, saving it as a .xml figure and with '''[Tools/make mask]''' as 'Dalsa1.mask/mask_bulk.png', with bounds in ''x'' [0 55].
    2626
    2727= PIV on the parietal plume =
    28 Open an image of the subfolder Dalsa1.sback (for instance Dalsa1_1_1.png) and open the GUI '''series''' to change the name at the bottom '''output !SubDir''' by ''Dalsa1.sback.civ_bulk''.
     28Open an image of the subfolder Dalsa1.sback (for instance Dalsa1_1_1.png) and open the GUI '''series''' to change the name at the bottom '''output !SubDir''' by 'Dalsa1.sback.civ_bulk'.
    2929
    30 Click then on 'civ_series' in the '''Action''' list to open the GUI '''civ_input'''. Choose the following parameters:
     30Click then on 'civ_series' in the '''[Action]''' list to open the GUI '''civ_input'''. Choose the following parameters:
    3131
    3232 * pair j=1-2 for Civ1 and Civ2 : it minimises the time interval which is needed to capture the large velocity in the plume.
     
    4242
    4343= Merging data on a common grid =
    44 Create a projection grid in phys coordinates. For that purpose, open a velocity field of ''Dalsa1.sback.civ_bulk'' with '''uvmat''', displayed in phys coordinates. Use the upper bar menu option '''Projection object/plane'''. Then in the GUI '''set_object''', choose the option '''[!ProjMode]=''''interp_lin'. Choose a mesh 0.1 cm in each direction, ranging from 0 to 58.8 in x and 0 to 55 in y. Press '''[REFRESH]''' to see the result of projection in the GUI '''view_field'''. Check the option '''nb_vec/4''' in '''view_field''' to reduce the number of vectors displayed on the plot.
     44Create a projection grid in phys coordinates. For that purpose, open a velocity field of 'Dalsa1.sback.civ_bulk' with '''uvmat''', displayed in phys coordinates. Use the upper bar menu option '''[Projection object/plane]'''. Then in the GUI '''set_object''', choose the option '''[!ProjMode]=''''interp_lin'. Choose a mesh 0.1 cm in each direction, ranging from 0 to 58.8 in x and 0 to 55 in y. Press '''[REFRESH]''' to see the result of projection in the GUI '''view_field'''. Check the option '''nb_vec/4''' in '''view_field''' to reduce the number of vectors displayed on the plot.
    4545
    46 Now in '''series''' open the PIV file ''Dalsa1.sback.civ_bulk'' as input. Then append the second file ''Dalsa1.sback.civ_plume'' using the menu bar selection '''!Open/Browse append...'''. Select '''[!ActionName]'''= 'merge_proj'. Set '''!FieldTransform''' to 'phys', and select the check box '''Projection Object'''. The plane for projection is then incorporated in '''series'''. It is also advised to introduce masks in the interpolation process so that each field is interpolated in its range of validity. This is done by selecting the check box '''Mask'''. Use the browser to fill the table of masks, in accordance with the table of input file series. Press '''[RUN]''' to launch the calculation. Then press '''[STATUS]''' to see the result with '''uvmat'''.
     46Now in '''series''' open the PIV file 'Dalsa1.sback.civ_bulk' as input. Then append the second file 'Dalsa1.sback.civ_plume' using the menu bar selection '''[!Open/Browse append...]'''. Select '''[!ActionName]'''= 'merge_proj'. Set '''[!FieldTransform]''' to 'phys', and select the check box '''Projection Object'''. The plane for projection is then incorporated in '''series'''. It is also advised to introduce masks in the interpolation process so that each field is interpolated in its range of validity. This is done by selecting the check box '''Mask'''. Use the browser to fill the table of masks, in accordance with the table of input file series. Press '''[RUN]''' to launch the calculation. Then press '''[STATUS]''' to see the result with '''uvmat'''.
    4747
    4848= Merging data using thin plate spline =