# Region

Use the Region tab to define the region on which the tool runs blob analysis. If no region is supplied, the tool performs blob analysis on the entire Current.InputImage buffer.

Some of the parameters that specify the train region or train origin can be specified in either degrees (the default specification) or radians. The underlying tool keeps the values in radians but the edit control performs the conversion to degrees when appropriate.

Parameter | Description
--- | ---
Region Shape | Select the shape of the input region. Selecting None=Use entire image means that the tool uses the entire input image. A Blob tool supports the following input region shapes: Circle Ellipse Polygon Rectangle RectangleAffine CircularAnnulusSection EllipitcalAnnulusSection The set of region-defining parameters that appear depend on the region shape you use.
Region Mode | Defines the bounding box for the region. Pixel Aligned Bounding Box encloses the defined region within a rectangle. This means that the portions of the image that are outside the defined region but within the bounding rectangle are included. Pixel Aligned Bounding Box Adjust Mask encloses the defined region within a rectangle, but masks out the image portions that are outside the region but inside the enclosing rectangle. The result is that the defined region is closer to what you specify.
Selected Space Name | The coordinate space in which the region is interpreted.
Select Mode | Available when Rectangle or RectangleAffine is the chosen Region Shape. Selects the set of parameters to use to define the rectangle. If RectangleAffine is chosen, note that the angle 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 of interest within the image. Adjust the shape's geometric properties so that its default size is based on the image and its Selected Space Name.