kuwahara_filter滤波器
kuwahara_filter滤波器im1 = kuwahara(im,5);
function = kuwahara(X,WINSZ)
% kuwahara_filter滤波器
% 对图像边界轮廓有较强的保护作用
% kuwahara nonlinear edge-preserving filtering
% 函数输入：
% X：二维图像矩阵
% WINSZ： window size
% 函数输出：
% Y：滤波图像
% Xpad：点扩展矩阵
% The Kuwahara filter 4块，(最直观的如下所示，5x5 pixels).
%
% ( aaab bb)
% ( aaab bb)
% (ac ac abcd bd bd)
% ( cccd dd)
% ( cccd dd)
if nargin < 2
WINSZ = 5;% 默认值
end
if ~isa(X,'double')
X = im2double(X);% double类型
end
Pad = floor(WINSZ/2);% 向下取整
Xpad = padarray(X,,'replicate');% 点扩展
% A = [ 1 2;
% 3 4 ];
% B = padarray(A,,'replicate','post')
% B =
% 1 2 2 2
% 3 4 4 4
% 3 4 4 4
% 3 4 4 4
% 3 4 4 4
= size(Xpad); % 求维数
Y = zeros(size(X));
nRowIters = length((Pad+1):(padRows-Pad));
count = 1;
for i = (Pad+1):(padRows-Pad)
for j = (Pad+1):(padCols-Pad)
% 分成每一个小窗，Q1~Q4
w = Xpad((i-Pad):(i+Pad),(j-Pad):(j+Pad));
wnw = w(1:(Pad+1),1:(Pad+1));
wne = w(1:(Pad+1),(Pad+1):WINSZ);
wsw = w((Pad+1):WINSZ,1:(Pad+1));
wse = w((Pad+1):WINSZ,(Pad+1):WINSZ);
% 计算方差
s = var();
m = mean();
= min(s);
% 计算均值
Y(i,j) = m(k);
end
end
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