Changes between Version 180 and Version 181 of UvmatHelp


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Timestamp:
Jan 23, 2015, 3:21:55 PM (6 years ago)
Author:
vaillant1p
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  • UvmatHelp

    v180 v181  
    9292 * '''Mouse motion:''' the local coordinates and field values are obtained by moving the mouse over a plotting axes. They are displayed in the text box '''[text_display]''' on the upper right.
    9393
    94  * '''Zoom:''' is activated by selecting the check box '''[!CheckZoom]''' on the upper right. Zoom in by pressing the left mouse button on the graph. Zoom out by pressing the right mouse button. Alternatively, a zoomed region can be displayed as a separate figure by selecting '''[!CheckZoomFig]''' and  drawing a rectangle with the mouse. The zoomed region can be translated  through the initial field by pressing the directional arrows of the keyboard.
    95 
    96  * '''Graph limits:''' they automatically adjust to the field when the check box '''[!CheckFixLimits]''' is not selected (default). Otherwise they remain fixed, and can be adjusted by the check boxes '''[num_MinX]''', '''[num_MaxX]''', '''[num_MinY]''', '''[num_MaxY]'''.
     94 * '''Zoom:''' is activated by selecting the check box '''!CheckZoom''' on the upper right. Zoom in by pressing the left mouse button on the graph. Zoom out by pressing the right mouse button. Alternatively, a zoomed region can be displayed as a separate figure by selecting '''[!CheckZoomFig]''' and  drawing a rectangle with the mouse. The zoomed region can be translated  through the initial field by pressing the directional arrows of the keyboard.
     95
     96 * '''Graph limits:''' they automatically adjust to the field when the check box '''!CheckFixLimits''' is not selected (default). Otherwise they remain fixed, and can be adjusted by the boxes '''[num_MinX]''', '''[num_MaxX]''', '''[num_MinY]''', '''[num_MaxY]'''.
    9797
    9898 * '''Coordinate aspect ratio:''' when '''[!CheckFixAspectRatio]''' is selected (the default option for images), the scale ratio for the  x and y coordinates is fixed to 1 by default (it can be manually adjusted by the edit box '''[num_AspectRatio]'''. When '''[!CheckFixAspectRatio]''' is not selected the graph scales along x and y automatically adjust to the figure size.
     
    138138
    139139=== 3.4 Navigation among field indices ===
    140 The field indices can be incremented or decremented by the push buttons  '''[runplus]''' ( '''+''') and  '''[runmin]''' ('''-''') respectively.  This scanning is performed  over the first index (i) or the second one (j), depending on the selection of the check boxes '''[scan_i]''' or '''[scan_j]''' respectively. The step for increment is set by the edit box '''[increment_scan]'''. If this box is blank (or does not contain a number) the next available file is opened.
     140The field indices can be incremented or decremented by the push buttons  '''[runplus]''' ( '''+''') and  '''[runmin]''' ('''-''') respectively.  This scanning is performed  over the first index (i) or the second one (j), depending on the selection of the check boxes '''scan_i''' or '''scan_j''' respectively. The step for increment is set by the edit box '''[increment_scan]'''. If this box is blank (or does not contain a number) the next available file is opened.
    141141
    142142[[Image(3-4 Navigation among fields indices.png)]]
     
    144144The current indices are displayed in the four edit boxes '''[i1], [i2], [j1], [j2]'''. The two first indices i1 and j1 are used for image series, while the second line i2, j2 is used to label the image pairs used for PIV data. The file indices can be directly set in these edit boxes, or equivalently in the edit box '''[!FileIndex]''' at the top of the GUI.
    145145
    146 For navigation with index pairs, the reference index, defined as the integer part of the mean value ((j1+j2)/2), is incremented. If the check box '''[fix_pair] ''' is selected,  the difference j1-j2 is then fixed while the reference index i or j is incremented. Else the pair with appropriate reference index is searched. In the case of multiple choices, the most largest index interval is chosen. This allows us to scan successive fields obtained with different image pairs (to deal with time evolving velocity fields).
     146For navigation with index pairs, the reference index, defined as the integer part of the mean value ((j1+j2)/2), is incremented. If the check box '''fix_pair ''' is selected,  the difference j1-j2 is then fixed while the reference index i or j is incremented. Else the pair with appropriate reference index is searched. In the case of multiple choices, the most largest index interval is chosen. This allows us to scan successive fields obtained with different image pairs (to deal with time evolving velocity fields).
    147147
    148148The maximum  value detected for each index is indicated by the boxes '''[last_i]''' and '''[last_j] ''' respectively.
     
    172172   * Intensity < 20: ('black mask') the vector in this place will be set to zero.
    173173   * 20 < Intensity < 200:('gray mask') the vector in this place will be absent.
    174    * Intensity>200  the vector will be computed  The mask corresponding to an image or velocity field can be displayed in the GUI '''uvmat''' by selecting the check box '''[view_mask]''' ('''[!CheckMask]''') on the upper left. Images with appropriate name can be automatically recognised by '''uvmat''' and civ functions, see [#a9-Masksandgrids section 9.1]. Otherwise file selection by a browser is proposed when '''[view_mask]''' is selected.
     174   * Intensity>200  the vector will be computed  The mask corresponding to an image or velocity field can be displayed in the GUI '''uvmat''' by selecting the check box '''view_mask''' ('''[!CheckMask]''') on the upper left. Images with appropriate name can be automatically recognised by '''uvmat''' and civ functions, see [#a9-Masksandgrids section 9.1]. Otherwise file selection by a browser is proposed when '''[view_mask]''' is selected.
    175175
    176176 * ''' Grid:''' List of numbers (in ASCII text) specifying the set of points where the PIV processing is performed. It specifies the number of points n and a corresponding list of x and y coordinates expressed in image pixels, as follows
     
    231231[[Image(help_scalar_titres.jpg)]]
    232232
    233 The greyscale images are described by a matrix A(npy,npx) of positive integers. The luminosity range depends on the camera dynamics (0 to 255 for 8 bit images, 0 to 65535 for 16 bit images). Luminosity represented with grey levels, according to the colorbar displayed on the right. The luminosity and contrast can be adjusted using the edit boxes '''[num_MinA]''' and '''[num_MaxA]''' : the luminosity level set by '''[num_MinA]''' (and levels below) is represented as black, and the luminosity level set by '''[num_MaxA]''' (or levels above) as white. When the check box '''[!CheckFixScalar]''' is not selected, these bounds are set automatically to the image minimum and maximum respectively. Then the image may appear dark if a single point is very bright, in that case a lower value must be set by '''[num_MaxA]'''. Greyscale images can be displayed with false colors, from blue to red, by unselecting the check box '''[CheckBW]'''.
     233The greyscale images are described by a matrix A(npy,npx) of positive integers. The luminosity range depends on the camera dynamics (0 to 255 for 8 bit images, 0 to 65535 for 16 bit images). Luminosity represented with grey levels, according to the colorbar displayed on the right. The luminosity and contrast can be adjusted using the edit boxes '''[num_MinA]''' and '''[num_MaxA]''' : the luminosity level set by '''[num_MinA]''' (and levels below) is represented as black, and the luminosity level set by '''[num_MaxA]''' (or levels above) as white. When the check box '''fix''' ([!CheckFixScalar]) is not selected, these bounds are set automatically to the image minimum and maximum respectively. Then the image may appear dark if a single point is very bright, in that case a lower value must be set by '''[num_MaxA]'''. Greyscale images can be displayed with false colors, from blue to red, by unselecting the check box '''B/W''' ('''[CheckBW]''').
    234234
    235235Note that greyscale images with low resolution are linearly interpolated on a finer mesh for nicer display. This interpolation can be also done as image processing by defining a grid on a projection object 'plane', see [#ProjObject section 6].
     
    237237Two images can be visually compared by switching back and forth between them as a short movie. This is quite useful to get a visual feeling of the image correlation for PIV. This effect is obtained by introducing two image indices in the edit boxes j1 and j2 (or i1 and i2), and selecting the button  '''[movie_pair] ''' (''''[<-->]'''') to switch between these two indices. The speed of the movie can be adjusted by the slider '''[speed]'''. Press '''[movie_pair] ''' again, or '''[STOP]''', to stop the motion.
    238238
    239 Scalar fields are  represented like greyscale images, by default with a false color map ranging from blue (minimum values) to red (maximum), or as gray scale images by selecting the check box '''[CheckBW]'''. Other color maps can be used by extracting the figure with the menu bar button '''[Export/extract figure]''', then using the standard  Matlab button '''[!Edit/Colormap]''' in the figure menu bar.
     239Scalar fields are  represented like greyscale images, by default with a false color map ranging from blue (minimum values) to red (maximum), or as gray scale images by selecting the check box '''B/W''' ('''[CheckBW]'''). Other color maps can be used by extracting the figure with the menu bar button '''[Export/extract figure]''', then using the standard  Matlab button '''[!Edit/Colormap]''' in the figure menu bar.
    240240
    241241Scalar are represented by matrices with real ('double') values, unlike images which are integers. They can be alternatively defined with unstructured grid (see [#a5.1Gridingofdata section 5.1]): they are then linearly interpolated on a regular grid before visualisation (a fairly slow process).
     
    244244Scalars (or image intensity) can be also represented with contour plots, by switching the popup menu '''[Contours] ''' from the setting 'image' to the setting 'contours'. Contours for positive scalar values are in sold line while contours for negative values are dashed. The interval between contours can be set by the edit box '''[num_IncrA]'''. The interval is automatically determined if the box content is blank.
    245245
    246 By default, the  contours are further marked by jumps of color levels. This can be set to grey levels by selecting the check box '''[CheckBW]. '''To suppress these images, set '''[Opacity]''' to 0.
     246By default, the  contours are further marked by jumps of color levels. This can be set to grey levels by selecting the check box '''B/W''' ('''[CheckBW]'''). To suppress these images, set '''[Opacity]''' to 0.
    247247
    248248=== 4.3 Vectors ===
    249 The vector fields are represented by arrows. The length of the arrows is automatically set by default, or can be adjusted by the edit box '''[num_VecScale]''' when the check box''' [!CheckFixVectors]''' is selected.  For clarity of visualisation, the number of displayed vectors can be divided by 4 or 16  by selecting the check box '''[!CheckDecimate4]''', or '''[!CheckDecimate16]''' respectively.
     249The vector fields are represented by arrows. The length of the arrows is automatically set by default, or can be adjusted by the edit box '''[num_VecScale]''' when the check box '''fix''' ('''[!CheckFixVectors]''') is selected.  For clarity of visualisation, the number of displayed vectors can be divided by 4 or 16  by selecting the check box '''nb_vec/4''' ('''[!CheckDecimate4]'''), or '''nb_vec/16''' ('''[!CheckDecimate16]''') respectively.
    250250
    251251Each vector has a color, ranging from blue to red, which can represent an associated  scalar value. In addition, black and magenta colors represent warning and error flags respectively. This color system is primarily designed for PIV data but can be used in other contexts as well.
     
    253253[[Image(help_vectors_titres.jpg)]]
    254254
    255 - '''Warning flags''': they indicate a vector resulting from a dubious image correlation process, but not removed from the data set. They are displayed in black by default. This feature can be desactivated by selecting the check box '''[!CheckHideWarning]'''.
    256 
    257 - '''Error flags''': they mark vectors considered as false. These vectors are kept in the data set so that their elimination can be reversed, but they must not be taken into account for data processing. These false vectors are displayed in magenta. They can be also removed from the plot by selecting the check box '''[!CheckHideFalse]'''.
     255- '''Warning flags''': they indicate a vector resulting from a dubious image correlation process, but not removed from the data set. They are displayed in black by default. This feature can be desactivated by selecting the check box '''hide warn''' ('''[!CheckHideWarning]''').
     256
     257- '''Error flags''': they mark vectors considered as false. These vectors are kept in the data set so that their elimination can be reversed, but they must not be taken into account for data processing. These false vectors are displayed in magenta. They can be also removed from the plot by selecting the check box '''hide false''' ([!CheckHideFalse]''').
    258258
    259259- '''Associated scalar: '''  for PIV velocity fields, the color  represents by default the image correlation '''C''', ranging from 0 to 1.  The red values correspond to poor correlations, green to fair values, and blue to good ones. The value range covered by each of the three colors is set by the pair of sliders  '''[Slider1]''' and '''[Slider2]''', or equivalently by the edit boxes '''[num_ColCode1]''' and '''[num_ColCode2]'''. Other color representations can be specified. '''[!ColorScalar]''' sets the scalar used for color representation, for instance the vector norm 'norm_vec' or vorticity 'vort' (the list of available scalars is set by the function {calc_scal.m}).
     
    261261- '''[!ColorCode] ''' sets the kind of color representation:
    262262
    263  * 'rgb':  color ranging from red, for the scalar value set by '''[num_MinVec]''', to blue, for the scalar value set by  '''[num_MaxVec]'''. The  color thresholds from red to green and green to blue are set by '''[ColCode1]''' and '''[ColCode2]''' respectively, or the sliders  '''[Slider1]''' and '''[Slider2]'''. By unselecting the check box [!CheckFixVecColor], these thresholds can be set to match the min and max scalar values.
     263 * 'rgb':  color ranging from red, for the scalar value set by '''[num_MinVec]''', to blue, for the scalar value set by  '''[num_MaxVec]'''. The  color thresholds from red to green and green to blue are set by '''[ColCode1]''' and '''[ColCode2]''' respectively, or the sliders  '''[Slider1]''' and '''[Slider2]'''. By unselecting the check box '''fix''' ('''[!CheckFixVecColor]'''), these thresholds can be set to match the min and max scalar values.
    264264 * 'black' or 'white': set the color for all vectors.
    265265 * 'brg': same as rgb but in reverse order, with blue for the lowest scalar values.
     
    272272 * third line: the vector index in the file, the values of the scalar (C), the warning flag (F) and the error flag (FF). The meaning of the flag values is given in [#a11.3FIX section 11.3].
    273273
    274 - '''Manual editing of vectors''': error flags are automatically produced by the PIV operation, see [#a11.3FIX section 11.3]. It is also possible to introduce them manually by checking '''[edit_vect]''' and selecting a vector with the mouse. The flag can be removed by selecting it again. To record the changes in the input file, press the button '''[record]'''.
     274- '''Manual editing of vectors''': error flags are automatically produced by the PIV operation, see [#a11.3FIX section 11.3]. It is also possible to introduce them manually by checking '''edit vect''' and selecting a vector with the mouse. The flag can be removed by selecting it again. To record the changes in the input file, press the button '''[record]'''.
    275275
    276276=== 4.4 Histograms ===
     
    816816[[Image(Correlation for PIV.png)]]
    817817
    818 The grid determines the positions of measured velocity vectors: it sets the central positions of the correlation boxes (in pixels) for the first image. A default regular grid can be set by the meshes '''[num_Dx] ''' and '''[num_Dy]''' (in pixels). Alternatively a custom [#a9.2Grids grid] can be stored in a text file and selected by the check box '''[GET_GRID]'''. This is convenient to limitate the processing to a subregion or to fine tune the resolution.
     818The grid determines the positions of measured velocity vectors: it sets the central positions of the correlation boxes (in pixels) for the first image. A default regular grid can be set by the meshes '''[num_Dx] ''' and '''[num_Dy]''' (in pixels). Alternatively a custom [#a9.2Grids grid] can be stored in a text file and selected by the check box '''get grid'''. This is convenient to limitate the processing to a subregion or to fine tune the resolution.
    819819
    820820A subregion can be alternatively selected by a mask image, selecting the edit box '''[Mask]'''. If a mask image with an appropriate name is found in the image directory, it wil be detected, and the indication 'xxmask' appears in the edit box. (xx is the number of slices, equal to 1 for a single mask). Otherwise a browser appears to select a (single) mask file.