Caliper length (i.e. Feret diameter) along minor axis of region.

A McMeasure object.  

object.mRgnWidth

The mRgnWidth Property syntax has these parts:

For this measurement, the region boundary is oriented along the major axis of an equivalent ellipse using the mRgnDirection measurement. mRgnDirection is a pixel-based measurement, so for regions created by the McThreshold.Execute method or McFeatures.SetFromMask method, holes in the blob are significant. The actual caliper is done using the orientated boundary polygon.

The smallest bounding rectangle aligned along the major axis of an equivalent ellipse may be gotten from the mRgnLength, mRgnWidth and mRgnDirection.