add MATLAB code

1 files changed, 27 insertions, 0 deletions

diff --git a/MATLAB/guidedfilter.m b/MATLAB/guidedfilter.m
new file mode 100755
index 0000000..9e9595e
--- /dev/null
+++ b/MATLAB/guidedfilter.m
@@ -0,0 +1,27 @@
+function q = guidedfilter(I, p, r, eps)

+%   GUIDEDFILTER   O(1) time implementation of guided filter.

+%

+%   - guidance image: I (should be a gray-scale/single channel image)

+%   - filtering input image: p (should be a gray-scale/single channel image)

+%   - local window radius: r

+%   - regularization parameter: eps

+

+[hei, wid] = size(I);

+N = boxfilter(ones(hei, wid), r); % the size of each local patch; N=(2r+1)^2 except for boundary pixels.

+

+mean_I = boxfilter(I, r) ./ N;

+mean_p = boxfilter(p, r) ./ N;

+mean_Ip = boxfilter(I.*p, r) ./ N;

+cov_Ip = mean_Ip - mean_I .* mean_p; % this is the covariance of (I, p) in each local patch.

+

+mean_II = boxfilter(I.*I, r) ./ N;

+var_I = mean_II - mean_I .* mean_I;

+

+a = cov_Ip ./ (var_I + eps); % Eqn. (5) in the paper;

+b = mean_p - a .* mean_I; % Eqn. (6) in the paper;

+

+mean_a = boxfilter(a, r) ./ N;

+mean_b = boxfilter(b, r) ./ N;

+

+q = mean_a .* I + mean_b; % Eqn. (8) in the paper;

+end
\ No newline at end of file