pregionconvexity

Measures region convexity degree.

Synopsis

pregionconvexity name [rg_in|-] [col_out|-]

Description

pregionconvexity measures the convexity degree of the regions inside the region map rg_in. Each region convexity degree is stored as a float in the array named name inside the collection col_out. The ith item in the array corresponds to the i+1th region because the region 0 is not considered.

Convexity is the relative amount that a region differs from a convex region. It is calculated as follows:

convexity = region area / convex hull area.

The maximum value is 1.0 for convex region (eg. circle, square).

Parameters

name is a string that contains the name of the array inside the collection.

Inputs

rg_in: a 2D region map.

Outputs

col_out: a collection.

Result

Returns SUCCESS or FAILURE.

Examples

Displays convexity of the regions yielded by a simple binarization of tangram.pan:

   pbinarization 100 1e30 tangram.pan a.pan
   plabeling 8 a.pan b.pan
   pregionconvexity convexity b.pan c.pan
   pcol2txt c.pan

C++ prototype

Errc PRegionConvexity( const Reg2d &rg_in, Collection &cold, const std::string &name );

Version française

Calcul de la convexité des régions.

Author: Alexandre Duret-Lutz