eccentricity

eccentricity_xld ( XLD : : : Anisometry, Bulkiness, StructureFactor )

Shape features derived from the ellipse parameters.

The operator eccentricity_xld calculates the three shape features Anisometry, Bulkiness, and StructureFactor derived from the geometric moments. The input contour must not intersect itself, otherwise the resulting parameters are not meaningful. If the input contour is not closed it will be closed automatically.

Definition: If the ellipse radii Ra, Rb (see elliptic_axis_xld) 
            and the enclosing area A of the contour are given,
            the following applies:
	      
   Anisometry = Ra / Rb
   
   Bulkiness = pi Ra Rb / A
   
   StructureFactor = Anisometry * Bulkiness - 1

Parameters

`XLD` (input_object)	xld(-array) `->` object
Contour(s) to be examined.

`Anisometry` (output_control)	real(-array) `->` real
Anisometry of the contour(s).
Assertion: `Anisometry >= 1.0`

`Bulkiness` (output_control)	real(-array) `->` real
Bulkiness of the contour(s).

`StructureFactor` (output_control)	real(-array) `->` real
Structure factor of the contour(s).

Result

The operator eccentricity_xld returns the value 2 (H_MSG_TRUE) if the input is not empty. The behavior in case of empty input (no input contours available) is set via the operator set_system('no_object_result',<Result>). If necessary an exception is raised.

Parallelization Information

eccentricity_xld is reentrant and automatically parallelized (on tuple level).

Possible Predecessors

gen_contours_skeleton_xld, edges_sub_pix, threshold_sub_pix, gen_contour_polygon_xld

Module

Sub-pixel operators