% GAUSSFILT -  Small wrapper function for convenient Gaussian filtering

%

% Usage:  smim = gaussfilt(im, sigma)

%

% Arguments:   im - Image to be smoothed.

%           sigma - Standard deviation of Gaussian filter.

%

% Returns:   smim - Smoothed image.

%

% If called with sigma = 0 the function immediately returns with im assigned

% to smim

%

% See also:  INTEGGAUSSFILT

% Peter Kovesi

% Centre for Explortion Targeting

% The University of Western Australia

% http://www.csse.uwa.edu.au/~pk/research/matlabfns/

% March 2010

% June  2013  - Provision for multi-channel images

function smim = gaussfilt(im, sigma)

    if sigma < eps

        smim = im;

        return;

    end

    % If needed convert im to double

    if ~strcmp(class(im),'double')

        im = double(im);  

    end

    sze = max(ceil(6*sigma), 1);

    if ~mod(sze,2)    % Ensure filter size is odd

        sze = sze+1;

    end

    h = fspecial('gaussian', [sze sze], sigma);

    % Apply filter to all image channels

    smim = zeros(size(im));

    for n = 1:size(im,3)

        smim(:,:,n) = filter2(h, im(:,:,n));

    end