Display matrices as color images
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The Matrix Viewer block displays an MbyN matrix input by mapping the matrix element values to a specified range of colors. The display is updated as each new input is received. This block treats an unoriented length M vector input as an Mby1 matrix.
You can use the Matrix Viewer block in models running in Normal or Accelerator simulation modes. The software does not support this block in models running in Rapid Accelerator or External mode. For more information about these modes, see How Acceleration Modes Work (Simulink) in the Simulink^{®} User's Guide.
Select the Image Properties tab to show the image property parameters, which control the colormap and display.
You specify the mapping of matrix element values to colors in the Colormap matrix, Minimum input value, and Maximum input value parameters. For a colormap with L colors, the colormap matrix has dimension Lby3, with one row for each color and one column for each element of the RGB triple that defines the color. Examples of RGB triples are
[ 1 0 0 ] (red) [ 0 0 1 ] (blue) [0.8 0.8 0.8] (light gray)
See the ColorSpec
property in the
MATLAB^{®} documentation for complete information about defining RGB
triples.
MATLAB provides a number of functions for generating predefined colormaps,
such as hot
, cool
,
bone
, and autumn
. Each of
these functions accepts the colormap size as an argument, and can be used in the
Colormap matrix parameter. For example, when you specify
gray(128)
for the Colormap matrix
parameter, the matrix is displayed in 128 shades of gray. The color in the first row
of the colormap matrix represents the value specified by the Minimum input
value parameter, and the color in the last row represents the value
specified by the Maximum input value parameter. Values between
the minimum and maximum are quantized and mapped to the intermediate rows of the
colormap matrix.
The documentation for the MATLAB
colormap
function provides complete
information about specifying colormap matrices, and includes a complete list of the
available colormap functions.
Select the Axis Properties tab to show the axis property parameters, which control labeling and positioning.
The Axis origin parameter determines where the first element
of the input matrix, U(1,1), is displayed. When you specify
Upper left corner
, the matrix is displayed in matrix
orientation, with U(1,1) in the upperleft corner.
$$\left[\begin{array}{cccc}{U}_{11}& {U}_{12}& {U}_{13}& {U}_{14}\\ {U}_{21}& {U}_{22}& {U}_{23}& {U}_{24}\\ {U}_{31}& {U}_{32}& {U}_{33}& {U}_{34}\\ {U}_{41}& {U}_{42}& {U}_{43}& {U}_{44}\end{array}\right]$$
When you specify Lower left corner
, the matrix is
flipped vertically to image orientation, with U(1,1) in the
lowerleft corner.
$$\left[\begin{array}{cccc}{U}_{41}& {U}_{42}& {U}_{43}& {U}_{44}\\ {U}_{31}& {U}_{32}& {U}_{33}& {U}_{34}\\ {U}_{21}& {U}_{22}& {U}_{23}& {U}_{24}\\ {U}_{11}& {U}_{12}& {U}_{13}& {U}_{14}\end{array}\right]$$
Axis zoom, when selected, causes the image display to completely fill the figure window. Axis titles are not displayed. This option can also be selected from the popup menu that is displayed when you rightclick in the figure window. When Axis zoom is cleared, the axis labels and titles are displayed in a gray border surrounding the image axes.
To customize the axis tick range, set Axis tick mode to
Userdefined
and specify a twoelement row vector,
[Minvalue Maxvalue
], in Xtick range and
Ytick range. The matrix data does not change even when the
axes ticks change. For example, consider displaying a matrix on axes with ticks
ranging from 0 to 10. When you set Xtick range and
Ytick range to [0 1], the range of ticks changes from [0
10] to [0 1].
The image title in the figure title bar is the same as the block title. The axis tick marks reflect the size of the input matrix; the xaxis is numbered from 1 to N (number of columns), and the yaxis is numbered from 1 to M (number of rows).
Rightclick the image in the figure window to access the following menu items:
Refresh erases all data on the scope display except for the most recent image.
Autoscale recomputes the minimum and maximum input values to fit the range of values observed in a series of 10 consecutive inputs. The numerical limits selected by the autoscale feature are shown in the Minimum input value and Maximum input value parameters, where you can make further adjustments to them manually.
Axis zoom, when selected, causes the image to completely fill the figure window. Axis titles are not displayed. When Axis zoom is cleared, the axis labels and titles are displayed in a gray border surrounding the scope axes. This option can also be set in the Axis Properties pane of the parameter dialog box.
Colorbar, when selected, displays a bar with the specified colormap to the right of the image axes.
Save Position automatically updates the Figure position parameter in the Axis Properties pane to reflect the figure window's current position and size on the screen. To make the scope window open at a particular location on the screen when the simulation runs, drag the window to the desired location, resize it, and select Save Position. The parameter dialog box must be closed when you select Save Position for the Figure position parameter to be updated.
The Image Properties pane of the Matrix Viewer block appears as follows.
A 3column matrix defining the colormap as a set of RGB triples, or a call
to a colormapgenerating function such as hot
or
spring
. See the ColorSpec
property for
complete information about defining RGB triples, and the MATLAB
colormap
function for a
list of colormapgenerating functions. Tunable (Simulink).
The input value to be mapped to the color defined in the first row of the
colormap matrix. Rightclick in the figure window and select
Autoscale
from popup menu to set this
parameter to the minimum value observed in a series of 10 consecutive matrix
inputs. Tunable (Simulink).
The input value to be mapped to the color defined in the last row of the
colormap matrix. Rightclick in the figure window and select
Autoscale
from the popup menu to set this
parameter to the maximum value observed in a series of 10 consecutive matrix
inputs. Tunable (Simulink).
Select to display a bar with the selected colormap to the right of the image axes. Tunable (Simulink).
The Axis Properties pane of the Matrix Viewer block appears as follows.
The position within the axes where the first element of the input matrix, U(1,1), is plotted; bottom left or top left. Tunable (Simulink).
The mode used to specify the axis tick range. When you select
Auto
, the xaxis tick
range and yaxis tick range are chosen based on the input
signal. When you select Userdefined
, the axis
tick range is set based on the values you specify in Xtick
range and Ytick range. The default is
Auto
.
xaxis tick range, specified as a twoelement row
vector of real scalars, [X_{min}
X_{max}]. This parameter applies only when you set Axis
tick mode to Userdefined
. When
you change Xtick range during simulation, the axis
range on the Matrix Viewer block updates in real time. The
default is [0 1
].
yaxis tick range, specified as a twoelement row
vector of real scalars, [Y_{min}
Y_{max}]. This parameter applies only when you set Axis
tick mode to Userdefined
. When
you change Ytick range during simulation, the axis
range on the Matrix Viewer block updates in real time. The
default is [0 1
].
The text to be displayed below the xaxis. Tunable (Simulink).
The text to be displayed to the left of the yaxis. Tunable (Simulink).
The text to be displayed to the right of the color bar, when Display colorbar is currently selected. Tunable (Simulink).
A 4element vector of the form [x y width height]
specifying the position of the figure window, where (0,0)
is the lowerleft corner of the display. Tunable (Simulink).
Resizes the image to fill the figure window. Tunable (Simulink).
Port  Supported Data Types 

Input 
