Search regions

When an Analysis and Processing step is processing an image, it can be beneficial to create a search region. A step that uses a search region will only consider what is in inside the region, and ignore the rest of the image. This can speed up processing by eliminating unnecessary work. Using a search region can also make a step more robust, minimizing any unwanted noise that might make a target difficult to find.

A search region can be a rectangle, elliptical arc, polygon, or elliptical ring sector. Once a search region is created in a step, other steps can use it as well. Note that not all steps can create search regions; and those that can, are not necessarily able to create all search region shapes.

Defining search regions

You can define a search region interactively on the selected step's displayed image, or by using the selected step's Configuration pane.

To create a search region interactively on the displayed image, click on the Define a region () toolbar button in the Project toolbar, and then click on the image to define the shape. The Quick Access pane should give you information about how to create the search region shape. Search region shapes can vary depending on the step you are using.

Whenever you create or redefine a shape interactively, a construction pop-up window will appear, as well as a yellow rubber band that connects the shape to its fixture. Set the shape's fixture (reference point and angle) in the construction pop-up window by selecting a fixture from the list.

To edit or move an existing search region interactively, click on its edge in the image. A bounding box will appear, allowing you to resize and re-orient the image.

To use a search region defined in another step, click the Use existing shapes button in the selected step's Configuration pane. Use the tree structure in the Link editor to select the search region you want to use. The shared search region will be updated automatically based on any changes to the original.

You can specify the dimensions of a search region using explicit values or expressions in the selected step's Configuration pane. It is common to use expressions derived from the dimensions of earlier steps to define a new shape. You can drag and drop values from the Quick Watch flyout panel of other annotations directly into a dimension field of the shape that you are defining. You can also write expressions for a shape's dimensions in the Link editor. Below is an example of a doughnut shape (an elliptical ring sector) with an inner radius defined from the radius of a previous step's annotation.

In some cases, when redefining a shape, if there are no expressions involved, it might be quicker to delete the current shape and draw a new one rather than editing its dimensions. To select the entire image as your search region from your current shape, click the Use whole image () toolbar button in the Project toolbar.

If a step's search region or test region is calculated through links or expressions, and the resulting search region falls entirely outside the image boundaries, an error will occur. You should make sure that none of your regions are out of range.