Blob Analyzer The following two results require the Calculate Blob Angle property to be true. Extrinsic Inertia Results A moment of inertia of the blob is a measure of the inertial resistance of the blob to rotation about a given axis. Extrinsic moments of inertia measure the moment of inertia about the X- Y axes of the Tool coordinate system. Extrinsic Moments of Inertia A moment of inertia of the blob is a measure of the inertial resistance of the blob to rotation about a given axis. Extrinsic moments of inertia measure the moment of inertia about the x- y axes of the Tool coordinate system.
ACEUser's Guide, 3.6.x, 18316-000 Rev A Page 421 Object Definition Elongation The degree of dispersion of all pixels belonging to the blob around its center of mass. The elongation of the blob is calculated as the square root of the ratio of the moment of inertia, about the minor axis, to the moment of inertia about the major axis. Object Definition Inertia Minimum Moment of inertia about the major axis, which cor- responds to the lowest moment of inertia. Inertia Maximum Moment of inertia about the minor axis, which cor- responds to the highest moment of inertia. Object Definition Principal Axes A reference system that is constituted of the major axis and the minor axis.
The major axis (X) is the axis about which the moment of inertia is smallest. Conversely, the minor axis (Y) is the axis about which the moment of inertia of the blob is the greatest. The principal axes are orthogonal and are iden- tified by the angle between the X-axis of the region of interest and the major axis of the blob.