my_jiaquan.m

均值滤波,加权滤波,中值滤波的MATLAB实例,用于图象及信号的处理

function [B] = my_jiaquan(file_name,block_size) 

% Works on a block of of size block_size x block_size (3x3, 5x5, 9x9). 
% We assume block_size is odd. 

A = imread(file_name); 
[m,n] = size(A); 

% We need to be able to apply median filter at the boundary pixels. 
% Assume the image has Neumann boundary conditions. 
% The easiest way to handle this is to set up a matrix A2 that has 
% the original image A in the center and copies the adjacent 
% pixel value around the edges. 

k = floor(block_size/2); % How far we need to extend border. 
A2 = zeros(m+2*k,n+2*k); 
A2(k+1:m+k,k+1:n+k) = A; % Original image in center. 

% Extend border pixels. 
% Handle the 4 corners first. 
A2(1:k,1:k) = A(1,1); % Upper left corner. 
A2(1:k,n+k+1:n+2*k) = A(1,n); % Upper right corner. 
A2(m+k+1:m+2*k,n+k+1:n+2*k) = A(m,n); % Lower right corner. 
A2(m+k+1:m+2*k,1:k) = A(m,1); % Lower left corner. 

% To handle the sides, we need to copy 1 row/column at a time. 
for i = 1:k 
A2(i,k+1:n+k) = A(1,1:n); % Upper. 
A2(k+1:m+k,n+k+i) = A(1:m,n); % Right. 
A2(m+k+i,k+1:n+k) = A(m,1:n); % Lower. 
A2(k+1:m+k,i) = A(1:m,1); % Left. 
end; 

% Apply median filter to form matrix B. 
B=zeros(m,n); 
pixel_block = zeros(1,block_size^2); 
for i = 1:m 
for j = 1:n 
% Determine pixel block. 
k = floor(block_size/2); 
A3=A2(i:i+2*k,j:j+2*k);
J=jiaquanFilter(block_size);
A4=A3.*J;
block_sum=sum(A4(:));
B(i,j) = block_sum; 
end
end

B = uint8(B); % For drawing purposes.