To Execute the Training
This page describes the procedures of the "Training" window used to edit
(create, change, remove) the samples from a classified image either by "pixel"
or by region ( make the segmentation previously).
Executing
the Training:
-
after clicking on Training... in the "Classification"
window, the user has access to the window to edit the classified samples;
-
The themes can be created directly in the Training
window or can be imported from a Thematic Information Layer, the procedures for
getting the themes are described below;
-
After getting the themes it is possible to edit the samples;
-
select the sample Type: Acquisition or Test. The "Training"
interface allows two types of samples acquisition: Acquisition or Test.
-
The samples obtained in the Acquisition mode are used in the
classification process and, the samples obtained by the Test mode are
used only for studying. Generally the test samples are imperfect acquisitions
that are stored for possible future use. The Acquisition mode is the "default";
if the user wants to use some of these samples as Test, select them
before the acquisition process or change them later;
-
the samples can be obtained editing the contours (Polygon or Rectangle
modes), or use the contours in a segmented image, see the procedures below.
Creating
Themes:
-
in the "Training" window, give the theme's Name
(for instance, Forest, Water etc);
-
click on Color... and select
a color for the theme being created;
-
click on Create. Notice that the theme is presented in the Themes
list.
Importing Themes:
-
in the "Training"
window, click on “Import...”;
-
in the "Categories and Infolayers"
window select the category and the IL that has the polygons to be imported;
-
click on “Apply”, in the “Categories and Infolayers”
window;
-
The polygons from the selected IL are imported as samples and the classes that
the polygons belong to are imported as themes;
-
click on Save to store the imported samples and themes.
Exporting Themes:
Option to export the themes to a thematic IL.
-
Select
the thematic category created previously;
-
type in
the output IL name;
-
select
the sample type that will be exported (test, acquisition or both);
-
click on Export.
Note:
Each theme is created as a thematic class, and the samples become polygons of
this class. In case there is a class previously created with the same name, the
samples will be associated to the previously created class, and the class is
not "recreated".
Getting
samples in the rectangle mode:
-
click on Rectangle and activate the Zoom Cursor (
)
in the main menu;
-
click over an image to define the sample upper left corner, drag
diagonally and click again to define the sample lower right corner;
-
click on Get. Notice that the sample appears in the
list with a number and its type (Acquisition or Test);
-
repeat
the steps above to create other themes and other samples. Try to include inside
each sample just the pixels corresponding to the same theme. Get the maximum
number of samples possible for the same theme, the larger the number of
samples, well selected, the better the precision for the theme classification;
-
click on Save to store the samples and themes defined.
Acquiring
samples in the polygon mode:
-
click on Polygon and disable the Area Cursor in
case it is active. Notice that the Polygon Editing buttons become
active, and, by default the Closed Line
option (Create CL) is active;
-
click
over the image to initiate a polygon. Each mouse click defines a polygon
vertex;
-
click the mouse right button (RB) to close the polygon (for more
details see Create Closed Lines
in the editing options);
-
click on Get. Notice that the sample appears in the
list with its number and its type (Acquisition or Test);
-
repeat
the step above to create other themes or other samples. Try to include inside
the samples just the pixels corresponding to the same theme. Get the maximum
number of samples possible for the same theme, the larger the number of
samples, well selected, the better the precision for the theme classification;
-
click on Save to store the samples and themes defined.
NOTE: Before acquiring the polygon sample the user can make small
adjustments in the polygon contour. Use the Add point, Move point
and Remove point tools (see more at vector editing
details). Once a sample is acquired it is not possible to edit it, the
only option is to remove it, if desired.
Acquiring
samples from a segmented image:
-
after having executed the segmentation, having defined
the context file (by regions) and having executed the Regions
Extraction, the user can use the segmented image as a sample contour.
Notice that in this case, besides the Polygon and Rectangle buttons,
also the Region
button is enabled;
-
select the segmented image (also called labeled image in the "Control
Panel") an show it in the active window. It is suggested to use the
original images (monochromatic or colored composition) as a background for the
segmented image;
-
click
over a region in the window;
-
click on Get. Notice that the sample appears in the
list with its number and its type (Acquisition or Test);
-
repeat
the steps above to create other themes or samples;
-
click on Save to store the samples and themes defined.
NOTES:
1- To change the theme color or name click on the list, change
the color and/or name and click on Change so the changes
will take effect.
2- To remove a theme or sample from the list, select a theme or sample
and click on Delete to remove it. Be careful when
deleting themes, because all samples associated to it will also be removed;
3- Click on View to draw in the active window the contour
of all samples of the selected theme, or just the selected sample. The sample
contour will be displayed using the color selected for the theme.
4- To change the sample type (Acquisition or Test), click
on the list, change the type and click on Change so
the changes will take effect;
5- Use the Zoom tool (Zoom Cursor )
to define the samples with higher precision.
6- After getting the samples, it is recommended to analyze
them, because in this way it is possible to change its type (from Acquisition
to Test) or even remove it, if it is not representative of the process.
7- After importing themes and samples, it is possible to edit them normally as
if they had been defined in the interface.
8- If desired
Save
the training file to use it in the
Neural Networks Training, click
on the
Exporting a Neural Networks File (SNNS)
option. In this way the file will be saved in two ways: with a ".pat" extension
and normal. Read more about
NEURAL NETWORKS TRAINING
If no more samples will be obtained, then the user can close the "Training"
window. Do not forget to Save before closing it.
Image
Classification
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