Changes between Version 11 and Version 12 of Tutorial/ParticleImageVelocimetry
- Timestamp:
- Dec 10, 2014, 12:01:37 AM (9 years ago)
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Tutorial/ParticleImageVelocimetry
v11 v12 33 33 34 34 == Histograms == 35 The global histograms of the vector components are available in the lower left windows. Histograms limited to a sub-region can be extracted by the menu bar tool '''[Projection object]''', selecting either ['''rectangle]''', '''[ellipse]''' or '''[polygon]''' to define the sub-region (see [wiki: "Tutorial: projection objects" Tutorial: projection objects])35 The global histograms of the vector components are available in the lower left windows. Histograms limited to a sub-region can be extracted by the menu bar tool '''[Projection object]''', selecting either ['''rectangle]''', '''[ellipse]''' or '''[polygon]''' to define the sub-region (see [wiki:Tutorial/ProjectionObjects: projection objects]) 36 36 37 37 == Profiles == … … 58 58 59 59 The time interval between the two images, Dt=0.02 s, must be introduced in this xml file by adding a section <Camera>, using a text editor: 60 < ImaDoc>60 <!ImaDoc> 61 61 <Camera> 62 < TimeUnit>s</TimeUnit>62 <!TimeUnit>s</TimeUnit> 63 63 <BurstTiming> 64 64 <Dti>0.02</Dti> 65 < NbDti>1</NbDti>65 <!NbDti>1</NbDti> 66 66 </BurstTiming> 67 67 </Camera> … … 91 91 This can be avoided by using a mask, which is an image of the same size as the images used for PIV. Grey color in the mask indicate regions excluded from measurement. 92 92 93 To produce the mask, first create a polygon by the menu bar command [Projection object/mask polygon]. Draw the mask with the mouse by moving around regions to exclude. Left mouse button to initiate the plot and produce new boundary points, press right hand button to finalise the polygon. By default mask is set inside the polygon, but it can be made outside by selecting the option ’mask_outside’ in the menu [ ProjMode] of the GUI set_object.93 To produce the mask, first create a polygon by the menu bar command [Projection object/mask polygon]. Draw the mask with the mouse by moving around regions to exclude. Left mouse button to initiate the plot and produce new boundary points, press right hand button to finalise the polygon. By default mask is set inside the polygon, but it can be made outside by selecting the option ’mask_outside’ in the menu [!ProjMode] of the GUI set_object. 94 94 95 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’).95 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’). 96 96 97 97 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, the mask is introduced by the selecting the green check box [Mask]. Vectors under the mask are not calculated in the resulting velocity data. … … 126 126 The following figure shows the final vorticity field, in which the vorticity roll up in the wake of the sphere is clearly visible. A zoom near a vortex shows the vorticity superposed with velocity vectors. 127 127 128 [[Image(vort_civ3 .jpg)]]128 [[Image(vort_civ3-2.jpg)]] 129 129 [[Image(vort_vel_zoom.jpg)]] 130 130
