# Use an Image Mask

You can use an image mask to exclude certain features from the image analysis during train time. The sensor does not train the masked area during the train time.

Note: The AlignSight application uses image mask only during the train time.

1. Click to set the train region over the pattern that you will use as the training model. Ensure that the train region covers only the feature of the pattern.

2. To open the Interactive Graphics Mode menu, right-click on the train region. Select Add Subregion > Region to add a sub-region.

3. Adjust the region to cover the area you want to mask.

4. To add a mask to the sub-region, right-click on the sub-region, and then select Subregion Operation > Subtract from the menu.

5. To confirm the mask region, click .

6. The area is masked in the image now. The icon replaces the train region, which indicates the location and angular orientation of the found pattern.