ANISOEDGE - Anisotropic diffusion edge detector.

Contents

Description

Implement the anisotropic diffusion edge detector proposed in [BSMH98].

Syntax

   edgemap = ANISOEDGE(I);
   edgemap = ANISOEDGE(I, sigma);
   [edgemap,mag] = ANISOEDGE(I, sigma, 'Property', propertyvalue, ...);

Inputs

I : input image.

sigma : optional standard deviation of the Gaussian filter used for smoothing of the image; typical range of values is [0.5,2]; default: sigma=1.

Property [propertyname propertyvalues]

'iter' : number of iterations used for smoothing; default: iter=100.

'max' : optional boolean flag for non-maximal suppression; when set to true, the detector is then supplemented with non-maximal suppression to produce single pixel wide edges; default: max=true.

Outputs

edgemap : a binary edge map.

mag : optional output image for the gradient magnitude.

References

[BSMH98] M. Black, G. Sapiro, D. Marimont and D. Heeger: "Robust anisotropic diffusion", IEEE Trans. Image Processing, 7(3,):421-432, 1998. http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=661192

[HSSB98] M. Heath, S. Sarkar, T. Sanocki, and K. Bowyer: "Comparison of edge detectors: a methodology and initial study", Computer Vision and Image Understanding, 69(1):38-54, 1998. http://www.sciencedirect.com/science/article/pii/S1077314297905877

Acknowledgment

This function uses the C functions developped in [HSSB98] by Christine Kranenburg available at http://marathon.csee.usf.edu/edge/.

See also

Ressembles: EDGECORNER, CANNYEDGE, CANNYEDGEPROD, SDGDEDGE, CONGRUENCYEDGE, COMPASSEDGE, ANISOEDGE, ELDERZUCKEREDGE, ROTHWELLEDGE, KOETHEDGE, PETROUEDGE. Requires: ANISOEDGE_BASE.

Function implementation

function [edgemap,varargout] = anisoedge(I, varargin)

check if possible

if ~exist('anisoedge_mex','file')
    error('anisoedge:mexfile','mex file anisoedge_mex not found');
end

error(nargchk(1, 14, nargin, 'struct'));
error(nargoutchk(1, 2, nargout, 'struct'));

if ~isnumeric(I)
    error('anisoedge:inputparameter','matrix required in input');
end

parsing parameters

p = createParser('ANISOEDGE');
p.addOptional('sigma',1., @(x)isscalar(x) && x>=0.1);
p.addParamValue('iter', 100, @(x)isscalar(x) && x>=1);
p.addParamValue('max', true, @(x)islogical(x));

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

main computation

[edgemap,tmpmag] = anisoedge_base(I, p.sigma, p.iter, p.max);

if nargout==2,  varargout{1} = tmpmag;  end;

display

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

end % end of anisoedge