HSI彩色图像空间滤波

HSI彩色图像空间滤波

1、代码

%HSI彩色图像空间滤波clc;clear all;close all;disp('彩色图像空间滤波开始.......');%%%提取3个分量图像f=imread('0.jpg');   %加载彩色图像%显示原图像figure;imshow(f);title('彩色原图像');h=rgb2hsi(f);   %rgb图像转化为HSIH=h(:,:,1);    %提取H通道分量图像S=h(:,:,2);    %提取S通道分量图像      I=h(:,:,3);    %提取I通道分量图像%显示三通道图像figure;subplot(2,2,1);imshow(H);title('H');subplot(2,2,2);imshow(S);title('S');subplot(2,2,3);imshow(I);title('I');%%%分别过滤每个分量图像w = fspecial('average', 3);i_filter=imfilter(I,w,'replicate');   %平滑蓝色分量图像%显示滤波后的三通道图像figure;imshow(i_filter);title('I滤波后');%%%重建滤波后的RGB图像hsi=cat(3,H,S,i_filter);%构造多维数组，即合并3分量图像为一副彩色图像%显示重建后的图像figure;imshow(hsi);title('重建后');%%%hsi滤波后转化为RGBrgb=hsi2rgb(hsi);figure;imshow(rgb);title('滤波转RGB结果');

（2）函数rgb2hsi（）定义

function hsi = rgb2hsi(rgb)% hsi = rgb2hsi(rgb)把一幅RGB图像转换为HSI图像，% 输入图像是一个彩色像素的M×N×3的数组，% 其中每一个彩色像素都在特定空间位置的彩色图像中对应红、绿、蓝三个分量。% 假如所有的RGB分量是均衡的，那么HSI转换就是未定义的。% 输入图像可能是double（取值范围是[0, 1]），uint8或 uint16。%% 输出HSI图像是double，% 其中hsi(:, :, 1)是色度分量，它的范围是除以2*pi后的[0, 1]；% hsi(:, :, 2)是饱和度分量，范围是[0, 1]；% hsi(:, :, 3)是亮度分量，范围是[0, 1]。% 抽取图像分量rgb = im2double(rgb);r = rgb(:, :, 1);g = rgb(:, :, 2);b = rgb(:, :, 3);% 执行转换方程num = 0.5*((r - g) + (r - b));den = sqrt((r - g).^2 + (r - b).*(g - b));theta = acos(num./(den + eps)); %防止除数为0H = theta;H(b > g) = 2*pi - H(b > g);H = H/(2*pi);num = min(min(r, g), b);den = r + g + b;den(den == 0) = eps; %防止除数为0S = 1 - 3.* num./den;H(S == 0) = 0;I = (r + g + b)/3;% 将3个分量联合成为一个HSI图像hsi = cat(3, H, S, I);

（3）函数hsi2rgb（）定义

function rgb = hsi2rgb(hsi)% rgb = hsi2rgb(hsi)把一幅HSI图像转换为RGB图像，% 其中hsi(:, :, 1)是色度分量，它的范围是除以2*pi后的[0, 1]；% hsi(:, :, 2)是饱和度分量，范围是[0, 1]；% hsi(:, :, 3)是亮度分量，范围是[0, 1]。%% 输出图像分量：% rgb(:, :, 1)为红；% rgb(:, :, 2)为绿；% rgb(:, :, 3)为蓝。% 抽取图像分量hsi = im2double(hsi);H = hsi(:, :, 1) * 2 * pi;S = hsi(:, :, 2);I = hsi(:, :, 3);% 执行转换方程R = zeros(size(hsi, 1), size(hsi, 2));G = zeros(size(hsi, 1), size(hsi, 2));B = zeros(size(hsi, 1), size(hsi, 2));% RG扇形(0 <= H < 2*pi/3)idx = find( (0 <= H) & (H < 2*pi/3));B(idx) = I(idx) .* (1 - S(idx));R(idx) = I(idx) .* (1 + S(idx) .* cos(H(idx)) ./ ...cos(pi/3 - H(idx)));G(idx) = 3*I(idx) - (R(idx) + B(idx));% BG扇形(2*pi/3 <= H < 4*pi/3)idx = find( (2*pi/3 <= H) & (H < 4*pi/3) );R(idx) = I(idx) .* (1 - S(idx));G(idx) = I(idx) .* (1 + S(idx) .* cos(H(idx) - 2*pi/3) ./ ...cos(pi - H(idx)));B(idx) = 3*I(idx) - (R(idx) + G(idx));% BR扇形idx = find( (4*pi/3 <= H) & (H <= 2*pi));G(idx) = I(idx) .* (1 - S(idx));B(idx) = I(idx) .* (1 + S(idx) .* cos(H(idx) - 4*pi/3) ./ ...cos(5*pi/3 - H(idx)));R(idx) = 3*I(idx) - (G(idx) + B(idx));% 将3个分量联合成为一个RGB图像rgb = cat(3, R, G, B);rgb = max(min(rgb, 1), 0);

2、运行结果