Define the grayvalue output mode.

set_paint defines the output mode for gray value display (single- or multichannel) in the window. The mode is used by disp_obj, disp_image, and disp_color.

This page describes the different modes that can be used for gray value output. It should be noted that the mode 'default' is the most suitable in almost all cases.

The hardware characteristics determine how gray values can be displayed. On a screen with one to seven bit planes, only binary data can be displayed. On screens with at least eight bit planes, it is possible to display multiple gray values. For binary displays, HALCON includes algorithms using a dithering matrix (fast, but low resolution), minimal error (good, but slow) and thresholding. Using the thresholding algorithm, the threshold can be passed as a second parameter (a tuple with the string 'threshold' and the actual threshold, e.g.: ['theshold', 100]).

Displays with eight bit planes use approximately 200 gray values for output. Of course it is still possible to use a binary display on those displays.

A different way to display gray values is the histogram (mode: 'histogram'). This mode has two additional parameter values: Row (second value) and column (third value). They denote row and column of the histogram center for positioning on the screen. The scale factor (fourth value) determines the histogram size: a scale factor of 1 distinguishes 256 grayvalues, 2 distinguishes 128 gray values, 3 distinguishes 64 gray values, and so on. The four values are passed as a tuple, e.g. ['histogram',256,256,1]. If only the first value is passed ('histogram'), the other values are set to defaults or the last values, respectively. For histogram computation see gray_histo. Histogram output honors the same parameters as procedures like disp_region etc. (e.g. set_color, set_draw, etc.)

Yet another mode is the display of relative frequencies of the number of connection components (“component_histogram“). For informations on computing the component histogram see shape_histo_all). Positioning and resolution are exactly as in the mode 'histogram'.

In mode 'mean', all object regions are displayed in their mean gray value.

The modes 'row' and 'column' allow the display of lines or columns, respecively. The position (row and column index) is passed with the second paramter value. The third parameter value is the scale factor in percent (100 means 1 pixel per grayvalue, 50 means one pixel per two gray values).

Gray images can also be interpreted as 3d data, depending on the grayvalue. To view these 3d plots, select the modes 'contourline', '3D-plot' or '3D-plot_hidden'.

Three-channel images are interpreted as RGB images. They can be displayed in three different modes. Two of them can be optimized by Floyd-Steinberg dithering.

Vector field images can be viewed as 'vector_field'.

All available painting modes can be queried with query_paint.

Paramters for modes that need more than one parameter can be passed the following ways:

- Only the name of the mode is passed: the defaults or the most
  recently used values are used.
  Example: set_paint(WindowHandle,'contourline')
- All values are passed: all output characteristics can be set.
  Example: set_paint(WindowHandle,['contourline',10,1])
- Only the first n values are passed: only the passed values are
  changed.
  Example: set_paint(WindowHandle,['contourline',10])
- Some of the values are replaced by an asterisk ('*'): The value of
  the replaced parameters is not changed.
  Example: set_paint(WindowHandle,['contourline','*',1])

Apart from set_paint there are other operators that affect the output of grayvalues. The most important of them are set_part, set_part_style,set_lut and set_lut_style. Some output modes display grayvalues using region output (e.g. 'histogram','contourline','3D-plot', etc.). In these modes, paramters set with set_color, set_rgb,set_hsi, set_pixel, set_shape, set_line_width and set_insert influence grayvalue output. This can lead to unexpected results when using set_shape('convex') and set_paint(WindowHandle,'histogram'). Here the convex hull of the histogram is displayed.

Modes:

one-channel images

  'default'
                    optimal display on given hardware
  'gray'
                    grayvalue output
  'mean'
                    mean grayvalue
  'dither4_1'
                    binary image, dithering matrix 4x4
  'dither4_2'
                    binary image, dithering matrix 4x4
  'dither4_3'
                    binary image, dithering matrix 4x4
  'dither8_1'
                    binary image, dithering matrix 8x8
  'floyd_steinberg'
                    binary image, optimal grayvalue simulation
  'threshold'
                    binary image, threshold: 128 (default)

  ['threshold',Threshold]
  ['threshold',200] 
                    binary image, any threshold: (here: 200)
  'histogram'
                    grayvalue output as histogram
                    position default: max. size, in the window center
  ['histogram',Row,Column,Scale]
  ['histogram',256,256,2]              
                    grayvalue output as histogram, any parameter values
                    positioning: window center (here (256,256))
                    size: (here 2, half the max. size)
  'component_histogram'
                    output as histogram of the connection components.
                    Positioning: default
  ['component_histogram',Row,Column,Scale]
  ['component_histogram',256,256,1]
                    output as histogram of the connection components.
                    Positioning: (here (256, 256))
                    Scaling: (here 1, max. size)
  'row'
                    output of the grayvalue profile along the given
                    line.
                    line: image center (default)
                    Scaling: 50%
  ['row',Row,Scale]
  ['row',100,20]   
                    output of the grayvalue profile of line 100 with
                    a scaling of 0.2 (20%).
  'column'
                    output of the grayvalue profile along the given
                    column.
                    column: image center (default)
                    Scaling: 50%
  ['column',Column,Scale]
  ['column',100,20]
                    output of the grayvalue profile of column 100 with
                    a scaling of 0.2 (20%).
  'contourline'
                    grayvalue output as contour lines:
                    the grayvalue difference per line is defined
                    with the parameter 'Step' (default: 30,
                    i.e. max. 8 lines for 256 grayvalues). The line
                    can be displayed in a given color (see
                    set_color) or in the grayvalue they
                    represent. This behaviour is defined with the
                    parameter 'Colored' (0 = color, 1 = grayvalues).
                    Default is color.
  ['contourline',Step,Colored]
  ['contourline',15,1]
                    grayvalue output as contour lines with a step of
                    15 and gray output.
  '3D-plot'
                    grayvalues are interpreted as 3d data: the
                    greater the value, the 'higher' the assumed
                    mountain. Lines with step 2 (second paramter
                    value) are drawn along the x- and y-axes.
                    The third parameter (Colored) determines, if the
                    output should be in color (default) or
                    grayvalues. To define the projection of the 3d
                    data, use the parameters EyeHeight and
                    EyeDistance. The projection parameters take
                    values from 0 to 255. ScaleGray defines a
                    factor, by which the grayvalues are multiplied
                    for 'height' interpretation (given in
                    percent. 100\% = factor 1). For extreme values of
                    EyeHeight and EyeDistance the image can be
                    shifted out of place. Use RowPos and ColumnPos
                    to move the whole output. Values from -127 to
                    127 are possible.
  ['3D-plot',Step,Colored,EyeHeight,EyeDistance,ScaleGray,RowPos,ColumnPos]
  ['3D-plot',5,1,110,160,150,70,-10]
                    line step:   5 pixel
                    Colored:     yes (1)
                    EyeHeight:   110
                    EyeDistance: 160
                    ScaleGray:   1.5 (150)
                    RowPos:      70 pixel down
                    ColumnPos:   10 pixel right
  '3D-plot_hidden'  
                    like '3D-plot', but computes hidden lines.
  ['3D-plot_hidden',Step,Colored,EyeHeight,EyeDistance,ScaleGray,RowPos,
   ColumnPos] 

Two-channel images:

  'default'
                    output the first channel.

Three-channel images:

  'default'
                    output as RGB image with 'median_cut'.
  'television'
                    color addition algorithm for RGB images: (three
                    components necessary for
                    disp_image). Images are displayed
                    via a fixed color lookup table. Fast, but
                    non-optimal color resolution. Only recommended on
                    bright screens.
  'grid_scan'
                    grid-scan algorithm for RGB images (three
                    components necessary for
                    disp_image). An optimized  color
                    lookup table is generated for each image. Slower
                    than 'television'. Disadvantages: Hard color
                    boundaries (no dithering). Different color lookup
                    table for every image.
  'grid_scan_floyd_steinberg'
                    grid-scan with Floyd-Steinberg dithering for
                    smooth color boundaries.
  'median_cut'
                    median-cut algorithm for RGB images (three
                    components necessary for
                    disp_image). Similar to grid-scan.
                    Disadvantages: Hard color boundaries (no
                    dithering). Different color lookup table for
                    every image.
  'median_cut_floyd_steinberg'
                    median-cut algorithm with Floyd-Steinberg
                    dithering for smooth color boundaries.

Vector field images:

  'vector_field'
                    output a vector field.
                    In this mode, a circle is drawn for each vector
                    at the position of the pixel.  Furthermore, a
                    line segment is drawn with the current vector.
                    The step size for drawing the vectors, i.e., the
                    distance between the drawn vectors, can be set
                    with the parameter Step.  Short vectors can be
                    suppressed with the third parameter value
                    (MinLength).  The fourth parameter value scales
                    the vector length. It should be noted that by
                    setting 'vector_field' only the internal
                    parameters Step, MinLengh, and ScaleLength are
                    changed.  The current display mode is not
                    changed.  Vector field images are always
                    displayed as vector field, no matter which mode
                    is selected with set_paint.
  ['vector_field',Step,MinLengh,ScaleLength]                 
  ['vector_field',16,2,3]
                    Output of every 16. vector, that is longer than 2
                    pixel. Each vector is multiplied by 3 for
                    output.

- Display of color images ('television', 'grid_scan', etc.) changes
  the color lookup tables.
- If a wrong color mode is set, the error message may appear not until
  the disp_image call.
- Grayvalue output may be influenced by region output parameters. This
  can yield unexpected results.

read_image(Image,'fabrik') 
open_window(0,0,-1,-1,'root','visible',"',WindowHandle) 
query_paint(WindowHandleModi) 
fwrite_string(['available gray value modes: ',Modi]) 
fnew_line() 
disp_image(Image,WindowHandle)  
get_mbutton(WindowHandle,_,_,_) 
set_color(WindowHandle,'red') 
set_draw(WindowHandle,'margin') 
set_paint(WindowHandle,'histogram') 
disp_image(Image,WindowHandle)  
set_color(WindowHandle,'blue') 
set_paint(WindowHandle,['histogram',100,100,3]) 
disp_image(Image,WindowHandle)  
set_color(WindowHandle,'yellow') 
set_paint(WindowHandle,['row',100]) 
disp_image(Image,WindowHandle)  
get_mbutton(WindowHandle,_,_,_) 
clear_window(WindowHandle) 
set_paint(WindowHandle,['contourline',10,1]) 
disp_image(Image,WindowHandle)  
set_lut(WindowHandle,'color') 
get_mbutton(WindowHandle,_,_,_) 
clear_window(WindowHandle) 
set_part(WindowHandle,100,100,300,300) 
set_paint(WindowHandle,'3D-plot') 
disp_image(Image,WindowHandle).

set_paint returns 2 (H_MSG_TRUE) if the parameter is correct and the window is valid. Otherwise an exception handling is raised.

set_paint is reentrant, local, and processed without parallelization.

query_paint, get_paint

disp_image

get_paint, query_paint, disp_image, set_shape, set_rgb, set_color, set_gray

Foundation