plocalextrema

Computes local extremum values of grayscale image.

Synopsis

plocalextrema connexity [-m mask] [im_in|-] [im_out|-]

Description

plocalmaxima builds the new image im_out with extremum pixels of the input image im_in. The value of the extremum pixel is the same as in the input image. All other pixels are set to 0.

A point is extremum if it is greater to at least one of two opposite neighbors and no lower than each of them:

   im_in[y][x] > im_in[y-1][x] et im_in[y][x] >= im_in[y+1][x]
   or
   im_in[y][x] >= im_in[y-1][x] et im_in[y][x] > im_in[y+1][x]

Parameters

connexity specifies the neighborhood relation (4, 8 in 2D) or (6, 26 in 3D). For graph, this parameter is ignored.

Inputs

im_in: a grayscale image.

Outputs

im_out: a grayscale image.

Result

Returns SUCCESS or FAILURE.

Examples

Detects the extrema in tangram.pan:

   plocalextrema 8 tangram.pan a.pan

C++ prototype

Errc PlocalExtrema( const Img2duc &im_in, Img2duc &im_out, int connexity );

Version française

Localisation des points constituant un extréma dans au moins direction.

Author: Régis Clouard