Basic concepts for the MIL Metrology module

Active edgels. The edgels within the metrology region that adhere to certain constraints.

Constructed feature. A geometric primitive that has been mathematically defined or geometrically derived from a set of other features.

Edge. A curve that delineates a boundary, which can be established from intensity transitions in an image.

Edgel. Elementary points (or edge elements) within an edge. Each edgel represents an X- and Y-position, and the angular direction of the gradient.

Fitted edgels. The active edgels that are used to build a fitted feature.

Geometric tolerance. The acceptable deviation from the definition of a feature, or the acceptable relationship between multiple features.

Global frame. The metrology template's default reference frame.

Gradient angle. The angle between the target image's horizontal axis and the edge's perpendicular direction (from black to white) at each edgel location.

Iterative fit. The calculated fit resulting from one of the iterations during the iteration process.

Local frame. A constructed reference frame.

(Physically) measured feature. A geometric primitive that can be physically measured using the edgels in the metrology region.

Metrology context. A MIL object that stores all features and geometric tolerances of the metrology template, and global processing settings.

Metrology region. The delimited area in the target image from which to select the edgels used to establish a physically measured feature. The features with which to build constructed features can also have a delimited metrology region.

Metrology region orientation. The alignment of a metrology region, with respect to a reference frame.

Metrology template. The set of all features and geometric tolerances.

Output frame. The coordinate system in which feature results are returned.

Parametrically constructed feature. A geometric primitive that has been mathematically defined, rather than geometrically derived from a set of other features.

Reference frame. The coordinate system in which features are defined and to which they are relative.

Target image. The image in which to extract physically measured features, build constructed features, and verify geometric tolerances.

Template reference. An image (or result buffer) that represents an example of a target image, used to help build or modify a metrology template.