MatLab實作均值濾波器

% 3*3 均值濾波
I2 = imread('peppers.png');
kernel_size = [3,3];
kernel = ones(kernel_size)/(kernel_size(1)*kernel_size(2));
padding_size = (kernel_size-1)/2;
img_height = size(I2,1);img_width = size(I2,2);img_channels = size(I2,3);
img_padding = zeros(img_height+padding_size(1)*2,img_width+padding_size(2)*2,img_channels);
img_padding(padding_size(1)+1:padding_size(1)+img_height, padding_size(2)+1:padding_size(2)+img_width, :) = I2;

img_filtered = I2;
img_filtered_1 = I2;
img_filtered_2 = I2;

for i = 1:img_height
    for j = 1:img_width
        img_filtered(i,j,:) = sum(sum(kernel.*img_padding(i:i+2*padding_size(1), j:j+2*padding_size(2),:)));
    end
end
% 或者
for c = 1:img_channels
    for i = 1:img_height
        for j = 1:img_width
            img_filtered_1(i,j,c) = conv2(img_padding(i:i+2*padding_size(1), j:j+2*padding_size(2),c),kernel,'valid');
        end
    end
    img_filtered_2(:,:,c) = conv2(I2(:,:,c),kernel,'same'); % 内部已以0 padding
end

figure,imshow(I2);
figure,imshow(img_filtered);
figure,imshow(img_filtered_1);
figure,imshow(img_filtered_2);
% img_filtered、img_filtered_1、img_filtered_2 均相等
if img_filtered == img_filtered_1
    fprintf('True\n'); % 輸出為True
end
if img_filtered == img_filtered_2
    fprintf('True\n'); % 輸出為True
end