pdistance1

Computes distance map to nearest contour.

Synopsis

pdistance1 d1 d2 d3 [-m mask] [im_in|-] [im_out|-]

Description

pdistance computes the distance map to the nearest contour. The output image im_out is a float image where each pixel is set with the distance to the nearest contour point. A contour is a chain of connected non null pixels.

The distance is computed from the specified distance between neighbors: d1, d2 and d3:

	+d2 +d1 +d2
	+d1  x  +d1
	+d2 +d1 +d2

For 3D, d3 is the distance between the diagonal neighbors.

If the input image is a graph then distance is computed from the node values.

Parameters

d1, d2 and d3 are real values that specify the distance metric. For example, the following metric can be used with convenient values:
- Euclidean: d1 = 1 ; d2 = sqrt(2), d3 = sqrt(3);
- Chessboard: d1 = 1 ; d2 = 2; d3 = 3;
- Manhattan: d1 = 1 ; d2 = 1; d3 = 1;

Inputs

im_in: a grayscale image (Img2duc or Img3duc) or a graph.

Outputs

im_out: a float image (Img2dsf or Img3dsf) or a graph.

Result

Returns SUCCESS or FAILURE.

Examples

Closed contours yielded by a simple edge detection of tangram.pan:

   psobel tangram.pan b.pan
   pbinarization 50 1e30 b.pan c.pan
   pskeletonization c.pan d.pan 
   ppostthinning d.pan e.pan
   pdistance1 1 1 1 e.pan f.pan
   plocalmaxima 8 f.pan g.pan
   plabeling 8 g.pan h.pan
   pinverse f.pan i.pan
   pwatershed h.pan i.pan j.pan
   pboundary 8 j.pan out.pan

C++ prototype

Errc PDistance1( const Img2duc &im_in, Img2dsf &im_out, float d1, float d2, float d3 );

Version française

Calcul d'une image de distance quelconque aux contours.

Author: Régis Clouard