Elongatedness

In image processing, elongatedness for a region is the ratio between the length and width of the minimum bounding rectangle of the region. It is considered a feature of the region. It can be evaluated as the ratio between the area of the region to its thickness squared:

e l o n g a t e d n e s s = l e n g t h w i d t h = a r e a ( 2 d ) 2 .

where the maximum thickness, d , of a holeless region is given by the number of times the region can be eroded before disappearing.