pregioncompactness

Measures region compactness factor.

Synopsis

pregioncompactness name [rg_in|-] [col_out|-]

Description

pregioncompactness measures compactness of the regions inside the region map rg_in. Each region compactness 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.

Compactness represents the degree to which the shape region is compact. It is defined as the ratio of the area of a region to the area of a circle with the same perimeter. It is calculated as follows:

compactness = (4*PI*area) / (perimeter*perimeter)

For a circle, the compactness is 1.0, for a square, it is PI/4 and for an infinitely long and narrow shape, it is zero.

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

   pbinarization 100 1e30 tangram.pan a.pan
   plabeling 8 a.pan b.pan
   pregioncompactness compactness b.pan c.pan
   pcol2txt c.pan

C++ prototype

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

Version française

Calcul de la compacité des régions.

Author: Alexandre Duret-Lutz