Example 2 - Performing a intra-regions segmentation

This example shows how to perform a simple segmentation and teaches some basic concepts about the interpretation process.

Database

Example 2 - Database

This zip file contains:

  • tijuca.tif
  • quadras.shp (city blocks)

Step by step

  • Start InterIMAGE. Click on FileNew Project and fill the fields according to the following:

Adding an image

  • Check the Default Image checkbox and click the Add button.
  • Add the shapefile quadras.shp. Click the Add button. After, click OK.

Adding a shapefile

  • Select the Shape tab and click the Add button. Set its Color to red, then click Save.

Adding a shape layerAdding a shape layer

  • Now, you should see something like this:

Layer rendered.

  • After, uncheck the Visible checkbox of the shape layer.
  • Create a semantic net like this one:

Semantic Net

  • Associate the TA_Shapefile_Import operator to the Blocks node. Set the operator parameters according to the image below. The CODIGO attribute is the block code in the shapefile.

Selecting the top-down operatorSetting the operator parameters

  • Associate a segmentation top-down operator to the Segmentation node. We will use the TA_Baatz_Segmenter operator in this example. Set the operator parameters according to the following:

Selecting the top-down operatorSetting the operator parameters

  • Click on FileSave Project. Click the Execute button. After the execution you should see something like this:

Analisys ready

  • Collapse the Blocks node. Once it's collapsed, select an object and see its attributes in the Object Information widget. Note that each block turned into a separate object and that the CODIGO attribute was successfully imported by the operator.

Blocks node collapsedSelect an objectObject Information widget

  • Expand back the Blocks node, select it and click the TopDown Decision Rule button.

Top-down decision rule

  • In the dialog that appears click the Class button and select the Blocks class. Click OK. Make sure that the Merge All option is selected and click OK again.

Decision Rule dialogInsert Class

  • Save the project and re-execute the interpretation.
  • Once the analysis is ready, collapse the Blocks node. Select an object and see its attributes in the Object Information widget. You should note that all blocks were merged into a single object. That's what the Merge All feature does.

Blocks merged into a single object

  • The previous behavior can be achieved again by selecting No Merge in the TopDown Decision Rule dialog.
  • Add a Roads node to the semantic net:

Semantic Net

  • Save the project and re-execute the interpretation. The result is explained by the default operator associated to the Roads node: Dummy Top-Down. It produces a hypothesis of Roads over the entire scene, so what's not Blocks (the gaps in the previous result) will automatically be classified as Roads.

Gaps are classified as Roads

  • The result can be better viewed if the Blocks node is collapsed. Try it out!