Image classifiers do not always provide the desired level of accuracy. As a result, a clean-up is often necessary after a classification. Aggregation is one of the four post-classification clean-up methods.
There are four main areas in the Aggregate window.
The file name and input and output channels to be used in the aggregation are listed at the top of the window. The input and output channels can be reset using the Setup button at the bottom of the window.
Use this area of the window to choose different ways to view the classes and aggregates.
Normal mode: Displays the aggregate classes along with the original, as yet unassigned, classes.
Input classes: Displays all the original input classes.
Current classes: Displays the classes that are currently selected in the Input Classes list.
Unassigned classes: Displays only the unassigned classes. Input classes that have been assigned to an aggregate will be blacked out.
Aggregate classes: Displays all the current aggregates.
Current aggregate classes: Displays the aggregates that are currently selected in the Aggregate Classes list.
Highlight color: Lets you choose a color for the class.
This table lists all of the classes in the selected input channel. Use this table to locate and select the set of classes to include in each of the aggregate classes. You can select multiple classes by holding down Shift or Ctrl while clicking a selection.
There are several tools available to assist you in the selection process:
Select Class at Cursor: Locates the class at the current cursor location within the view pane.
Highlight Classes: Displays the selected input classes in the chosen highlight color, as selected in the View Controls area.
PCT: Changes the current pseudocolor table.
Add: Adds the selected input classes to the selected aggregate class.
Remove: Removes the selected input classes from the selected aggregate class.
This table contains a list of all the aggregate classes. In addition, there are four tools available to assist you:
New: Creates a new aggregate class.
Delete: Removes an aggregate class from the list.
Class Initialization: Use the Class Initialization window to initialize a new set of classes. You can import entries for the class table from a classification channel or from a text file.
Save: Saves all the details of the aggregation session to a text file.
The following example of a text file that describes three aggregate classes:
1 | Water |0 |0 |255 | Water class | 10,20 2 | Crop |0 |255 |0 | Crops | 3 | Other Class |255 |0 |0 | Water class | 40
To help you to identify and locate classes, use the Highlight color feature in the View Controls area of the window. The selected class(es) assume the highlight color. Use the Highlight color palette to change the color used for highlighting.
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