Template Matching

Classification using the Template Matching Algorithm

As described in the Reference Book > Template Matching you can apply templates generated with eCognitions Template Matching Editor to your imagery.

Please refer to our template matching videos in the eCognition Knowledge-Base covering a variety of application examples and workflows.

The typical workflow comprises two steps. Template generation using the template editor, and template application using the template matching algorithm.

To generate templates:

Create a new project
Open View > Windows > Template Editor
Insert samples in the Select Samples tab
Generate template(s) based on the first samples selected

Exemplary Tree Template in the Template Editor

Test the template on a subregion resulting in potential targets
Review the targets and assign them manually as correct, false or not sure (note that targets classified as correct automatically become samples)
Regenerate the template(s) on this improved sample basis
Repeat these steps with varying test regions and thresholds, and improve your template(s) iteratively
Save the project (saves also the samples)

To apply your templates:

Create a new project/workspace with imagery to apply the templates to
Insert the template matching algorithm in the Process Tree Window

Template Matching Algorithm to generate Correlation Coefficient Image Layer

To generate the a temporary layer with correlation coefficients (output layer) you need to provide
- the folder containing the template(s)
- the layer that should be correlated with this template

RGB Image Layer (left) and Correlation Coefficient Image Layer (right)

To generate in addition a thematic layer with points for each target you need to provide a threshold for the correlation coefficient for a valid target

Template Matching Algorithm to generate Thematic Layer with Results

Apply the template matching algorithm
Segment your image based on the thematic layer and use the “assign class by thematic layer” algorithm to classify your objects

Assign Classification by Thematic Layer Algorithm

Review your targets using the image object table (zoom in and make only a small region of the image visible, and any object you select in the table will be visible in the image view, typically centered).