matlab 双边滤波(彩色图)

% matlab 2012b
% 彩色图的双边滤波
clc;
clear;
src=imread('cs.jpg');        %加载彩色图
%-------双边滤波 参数 -----------------
r = 20;   %半径   窗口 长 = 宽 = 2*r+1
sigma_space = 15.0;          %空间标准差
sigma_color = 10.0;          %相似标准差
w_space = zeros(1,r+1);      %空间权重
for i = 1:r+1                %i为横坐标之差的绝对值 + 1
    for j = 1:r+1            %j为纵坐标之差的绝对值 + 1
        w_space(i,j) = exp(-double((i-1)^2 + (j-1)^2) / (2 * sigma_space^2));
    end
end
w_color = zeros(1,256);      %相似权重
for i = 1:256                %i为像素值之差的绝对值 + 1
    w_color(i) = exp(-double((i-1)^2) / (2 * sigma_color^2));
end
%disp(w_space);
%disp(w_color);
%break;
%--------- 进行滤波 ------------------
src=double(src);       
[height,width,channel] = size(src); 
if channel ~= 3              %判断是否为3通道彩色图
   break;                    %不是则退出函数
end
dst = src;
for h = 1+r:height-r
    for w = 1+r:width-r          %窗口中心
        for c = 1:channel        %彩色图 三通道
            w_sum = 0;           %权值和
            p_sum = 0;           %权值未归一化与像素值的乘积和
            p_c = src(h,w,c);    %中心像素点的值
            for j = h-r:h+r
                for i = w-r:w+r                  %遍历窗口内的像素
                    p_t = src(j,i,c);            %像素点的值 以及未归一化的权值
                    w_tmp = w_space(abs(i-w)+1,abs(j-h)+1) * w_color(abs(p_c-p_t)+1);
                    p_sum = p_sum + p_t * w_tmp; %权值未归一化与像素值的乘积和
                    w_sum = w_sum + w_tmp;       %权值和
                end
            end
            p_sum = p_sum / w_sum; %归一化 
            dst(h,w,c) = p_sum;      %赋值
        end
    end
end

%转换格式 显示
src = uint8(src);
dst = uint8(dst);
subplot(121),imshow(src);
subplot(122),imshow(dst);

参考：
https://blog.csdn.net/l_eop/article/details/81812277
https://blog.csdn.net/qq_36359022/article/details/80198890
opencv源码 bilateral_filter.cpp