PETROUEDGE - Edge detection based on optimal ramp filter.

Contents

Description

Implements the edge detector of [PK91] derived from optimal filters for ramp edges.

Syntax

   emap = PETROUEDGE(I);
   emap = PETROUEDGE(I, mask);

Inputs

I : input image, possibly multichannel.

mask : ((optional) indice of the mask used by Petrou & Kittler edge detector for smoothing the input image; it is either 0, 1 or 2; default: mask=0.

Outputs

emap : edge map.

References

[Spac86] L.A. Spacek: "Edge detection and motion detection", Image & Vision Computing, 4:43-56, 1986. http://www.sciencedirect.com/science/article/pii/0262885686900077

[PK91] M. Petrou and J. Kittler: "Optimal edge detectors for ramp edges", IEEE Trans on Pattern Analysis and Machine Intelligence, 13(5):483-491, 1991. http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=134047

See also

Ressembles: EDGECORNER, CANNYEDGE, CANNYEDGEPROD, CANNYEDGEMAP, SDGDEDGE, CONGRUENCYEDGE, COMPASSEDGE, ANISOEDGE, ELDERZUCKEREDGE, KOETHEDGE, ROTHWELLEDGE. Requires: PETROUEDGE_BASE.

Function implementation

function edgemap = petrouedge(I,varargin)

parsing and checking parameters

error(nargchk(1, 10, nargin, 'struct'));
error(nargoutchk(1, 1, nargout, 'struct'));

% mandatory parameter
if ~isnumeric(I)
    error('petrouedge:inputparameter','matrix required in input');
end

p = createParser('PETROUEDGE');   % create an instance of the inputParser class.
p.addOptional('mask',0, @(x) isscalar(x) && any(x==0 |x==1|x==2));

% parse and validate all input arguments
p.parse(varargin{:});
p = getvarParser(p);

main calculation

edgemap = petrouedge_base(I, p.mask);

display

if p.disp
    figure, imagesc(edgemap), axis image off, title('Petrou&Kittler edge map');
    if size(edgemap,3) == 1, colormap gray;  end;
end

end % end of petrouedge