Changes between Version 171 and Version 172 of UvmatHelp


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Timestamp:
Jan 23, 2015, 10:02:24 AM (6 years ago)
Author:
vaillant1p
Comment:

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  • UvmatHelp

    v171 v172  
    646646 * <!NbSlice_j>: nbre of slices for the second index j (volume scan), =1 by default.
    647647
    648  * <!SliceCoord>: [x y z] positions (nb lines) of the nb planes, where nb=[wiki:NbSlice !NbSlice]_i (multilevel case) or nb=[wiki:NbSlice !NbSlice]_j of j indices (volume scan), for parallel volume scan, x=y=0, z= slice height, for angular scan, [x,y,z]=[origin].
     648 * <!SliceCoord>: [x y z] positions (nb lines) of the nb planes, where nb=!NbSlice_i (multilevel case) or nb=!NbSlice_j of j indices (volume scan), for parallel volume scan, x=y=0, z= slice height, for angular scan, [x,y,z]=[origin].
    649649
    650650 * <SliceDZ>:   step distance between planes.
     
    663663
    664664=== 9.2 Grids ===
    665 Grid files, see [#MaskGrids section 3.6], are used to impose a set of positions for PIV vectors. To create a grid for PIV, activate the menu bar Tools/Make grid on the GUI '''uvmat'''. Introduce a minimum value, mesh, and maximum value for coordinate ''x'' in the edit boxes '''[XMin], [DX], [XMax]''' respectively. Do the same for the ''y'' coordinate.  This must be expressed in physical coordinates.
     665Grid files, see [#MaskGrids section 3.6], are used to impose a set of positions for PIV vectors. To create a grid for PIV, activate the menu bar !Tools/Make grid on the GUI '''uvmat'''. Introduce a minimum value, mesh, and maximum value for coordinate ''x'' in the edit boxes '''[XMin], [DX], [XMax]''' respectively. Do the same for the ''y'' coordinate.  This must be expressed in physical coordinates.
    666666
    667667The grid will be limited to an  image , or to the common region of two images, depending whether one or two image names are indicated in the edit boxes image_1 and image_2. Press save to save the corresponding grid file (s). A dialog box appears to edit the name of the output grid file, and a second one in case of two images.
     
    824824The FIX operation is used after civ to mark false vectors, using different criteria:
    825825
    826 ''' - warning flags: ''' these are flags (vec_F) indicating problems with the image correlation process.
     826''' Warning flags: ''' these are flags (vec_F) indicating problems with the image correlation process.
    827827 * vec_F=-2: select to eliminate vectors for which the maximum of the correlation function is close to the border of the search box (at a distance of two pixels or less), so that its maximum cannot be reliably obtained.
    828828 * vec_F=3: the optimisation of the correlation function is unstable  or  local Intensity rms of the image =0. Must be selected.
    829829 
    830 ''' - Threshold on the image correlation:  ''' (vec_C) can be introduced by the edit box '''[num_!MinCorr]''' (value between 0 and 1). It removes vectors with poor correlation. 
    831 
    832 ''' - Threshold on the velocity modulus: ''' (expressed in pixels). It can remove either excessive values (threshold set by '''[num_MaxVel]''') or too small values (threshold set by '''[num_MinVel]'''). Erratic zero velocity vectors, produced by a fixed image background, can be eliminated by the latter criterium.
    833 
    834 ''' - Manual fix: ''' Interactive fixing with the mouse is also possible, see [section 4.2->#4.2].
     830''' Threshold on the image correlation:  ''' (vec_C) can be introduced by the edit box '''[num_!MinCorr]''' (value between 0 and 1). It removes vectors with poor correlation. 
     831
     832''' Threshold on the velocity modulus: ''' (expressed in pixels). It can remove either excessive values (threshold set by '''[num_MaxVel]''') or too small values (threshold set by '''[num_MinVel]'''). Erratic zero velocity vectors, produced by a fixed image background, can be eliminated by the latter criterium.
     833
     834''' Manual fix: ''' Interactive fixing with the mouse is also possible, see [#a4.2Contourplots section 4.2].
    835835
    836836
     
    861861Perform usual PIV for each image series.
    862862
    863 For PIV near a staigth wall, it is advised to create a grid for each image series, corresponding to a common array of physical positions. This can be done by the upper menu bar option '''!Tools/Make Grid''' in the GUI '''uvmat'''( see section [#a9.2Grids]).
     863For PIV near a staigth wall, it is advised to create a grid for each image series, corresponding to a common array of physical positions. This can be done by the upper menu bar option '''!Tools/Make Grid''' in the GUI '''uvmat'''( see section [#a9.2Grids Grids]).
    864864
    865865Combine PIV fields: TO UPDATE**.