pdensityselection

Selects regions from density degree.

Synopsis

pdensityselection relation threshold [-m mask] [rg_in|-] [im_in|-] [rg_out|-]

Description

pdensityselection selects regions from their density factor. The parameter relation specifies the order relation to the threshold value that is used to select or not a region.

Density measures the ratio nbetween the number of pixels in the region given in im_in and the area surface of the region in rg_in. It is calculated using:

density = number of pixel / area.

Parameters

relation is an integer from [-3,3] which specifies the order relation to the threshold value:
- relation = 3: regions with the maximum value.
- relation = 2: regions >= threshold.
- relation = 1: regions > threshold.
- relation = 0: regions = threshold.
- relation = -1: regions < threshold.
- relation = -2: regions <= threshold.
- relation = -3: regions with the minimum value.
threshold is a real value from [0..1] which specifies a density degree.

Inputs

rg_in: a 2D region map.
im_in: a 2D image of bytes.

Outputs

rg_out: a 2D region map.

Result

Returns the number of selected regions.

Examples

Selects regions with the highest density factor:

   pdensityselection 3 0 a.pan tangram.pan b.pan

C++ prototype

Errc PDensitySelection( const Reg2d &rg_in, const Img2duc &ims, Reg2d &rg_out, int relation, float threshold );

Version française

Sélection de régions sur leur valeur de sphéricité.

Author: Régis Clouard