# Region

Use the Region tab to select the shape of the input region:

Parameter | Description
--- | ---
Region Mode | Defines how the tool interprets the training region you specify. Choose either of the following options: Pixel Aligned Bounding Box processes all of the input image within a bounding box surrounding the region shape you are currently using. Affine Transform is valid only if you specify a RectangleAffine for the region shape, where the pixels within the affine rectangle undergo an affine transformation to remove the effect of any rotation and skew.
Region Shape | Select the shape of the input region. Selecting "None = Use Entire Image" means that the tool uses the entire input image. An Image Average tool supports the following input region shapes: Circle Ellipse Polygon Rectangle RectangleAffine CircularAnnulusSection EllipticalAnnulusSection The set of region-defining parameters that appear depend on the region shape you use.
Selected Space Name | The coordinate space in which the copy region is interpreted. For more information, see the topic Coordinate Space Names.
Select Mode | Available when Region Shape is Rectangle or RectangleAffine, selects the set of parameters that define the rectangle. If you choose RectangleAffine, note that the angles of rotation and skew can be specified in degrees or radians, although the underlying tool keeps the measurements in radians.
Fit In Image | Centers the region within Current.InputImage.