image - RGB 图像的 Matlab 低通滤波器

Question

我有这段代码可以对图像执行高斯滤波器(低通滤波器)。但是，该滤镜仅适用于灰度图像。我该如何改进它才能处理彩色图像？我知道有很多内置函数，但我是图像处理新手，我正在尝试学习基础知识。

%Read an Image
Img = imread('peppers.png');
Im = rgb2gray(Img);
I = double(Im);

%Design the Gaussian Kernel
%Standard Deviation
sigma = 1.76;

%Window size
sz = 4;
[x,y]=meshgrid(-sz:sz,-sz:sz);

M = size(x,1)-1;
N = size(y,1)-1;
Exp_comp = -(x.^2+y.^2)/(2*sigma*sigma);
Kernel= exp(Exp_comp)/(2*pi*sigma*sigma);

%Initialize
Output=zeros(size(I));
%Pad the vector with zeros
I = padarray(I,[sz sz]);

%Convolution
for i = 1:size(I,1)-M
    for j =1:size(I,2)-N
        Temp = I(i:i+M,j:j+M).*Kernel;
        Output(i,j)=sum(Temp(:));
    end
end
%Image without Noise after Gaussian blur
Output = uint8(Output);
figure,imshow(Output);

Answer 1

RGB 图像由红、绿、蓝颜色 channel 组成。对RGB图像进行图像处理

1. 您必须分离出图像的三个组成部分
2. 处理每个组件(R、G、B)一次

3. 根据修改后的 R、G、B 重建图像

   img = imread('peppers.png');
   R = img(:,:,1); %get the Red part
   G = img(:,:,2); %get the Blue part
   B = img(:,:,3); %get the Green part
   R_gaussian = gaussianFilter(R); %write your own function name
   G_gaussian = gaussianFilter(G); %or repeat the code by REPLACING I as 
   B_gaussian = gaussianFilter(B); %Red Green Blue components
   RGB_gaussian = cat(3,R_gaussian, G_gaussian, B_gaussian); %merging the components
   %since you are learning you can do this for better unedrstanding
   RGB_gaussian = zeros(size(img)); %make a matrix of size  of original image
   RGB_gaussian(:,:,1)=R_gaussian; % Replace the values  
   RGB_gaussian(:,:,2)=G_gaussian;
   RGB_gaussian(:,:,3)=B_gaussian;
   

有关更多信息，这可能会有所帮助:http://www.bogotobogo.com/Matlab/Matlab_Tutorial_Digital_Image_Processing_6_Filter_Smoothing_Low_Pass_fspecial_filter2.php