【数字图像处理matlab】(IHS变换融合算法）

【数字图像处理matlab】(IHS变换融合算法）

输入一张高分辨率的全色影像HR，一张低分辨率的多光谱影像MS，采用HSI变换融合算法实现影像融合，其中RGB与HSI影像的相互转换调用自定义函数RGB2HSI()，HSI2RGB()，函数具体代码为。

IHS变换融合步骤：

1. RGB2HSI()

RGB转IHS，原理：

function Image1=RGB2HSI(image)
%调用代码-------------------------------------------
%imageR=imread('animal.jpg');  
%RGB2HSI(image);
%--------------------------------------------------

image=im2double(image);
%从三维数组中提取三幅分量图像
R1=image(:,:,1);
G1=image(:,:,2);
B1=image(:,:,3);
I=(R1+G1+B1)/3;        %亮度分量，范围[0,1]
m=min(min(R1,G1),B1);
S=1-3*m./(R1+G1+B1);    %饱和度分量，范围[0,1]
theta=acos(((R1-G1)+(R1-B1))./(2*((R1-G1).^2+((R1-B1).*(G1-B1))).^(1/2))); %弧度 
H=theta;   %色度分量，以角度表示，范围是[0,1]（弧度除以2*pi后）
if B1>G1
    H=2*pi-theta;       
end     
if S==0
    H=0;
end
H=H/(2*pi);
Image1=cat(3,H,S,I);
subplot(1,2,1),imshow(image);
title('RGB原图')
subplot(1,2,2),imshow(Image1);
title('转换后的HSI图像')
end

2. HSI2RGB()

IHS转RGB，原理

function rgb= HSI2RGB(hsi) 
H = hsi(:, :, 1) * 2 * pi; 
S = hsi(:, :, 2); 
I = hsi(:, :, 3); 

R = zeros(size(hsi, 1), size(hsi, 2)); 
G = zeros(size(hsi, 1), size(hsi, 2)); 
B = zeros(size(hsi, 1), size(hsi, 2)); 

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)); 

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)); 

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)); 

rgb = cat(3, R, G, B); 
rgb = max(min(rgb, 1), 0); 
figure,
%subplot(1,2,1),
imshow(rgb);title('转换回的RGB图像') 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
H1 = hsi(:, :, 1) * 2 * pi; 
S1 = hsi(:, :, 2); 
I1 = hsi(:, :, 3);
R1 = zeros(size(hsi, 1), size(hsi, 2)); 
G1= zeros(size(hsi, 1), size(hsi, 2)); 
B1 = zeros(size(hsi, 1), size(hsi, 2));
if 0<=H1<2*pi/3;
    B1=I1.*(1-S1);
    R1=I1.*(1+(S1.*cos(H1)./cos(pi/3-H1)));
    G1=3.*I1-(B1+R1);   
elseif((2*pi/3<=H1)&&(H1<4*pi/3));
       R1=I1.*(1-S1);
        G1=I1.*(1+(S1.*cos(H1-2*pi/3)./cos(pi-H1)));
        B1=3.*I1-(R1+G1); 
else((4*pi/3<=H1)&(H1<2*pi));
    G1=I1.*(1-S1);
    B1=I1.*(1+(S1.*cos(H1-4*pi/3)./cos(10*pi/6-H1)));
    R1=3.*I1-(G1+B1);
end
r=cat(3,R1,G1,B1);
r=max(min(r,1),0);
subplot(1,2,2),imshow(r);
title('转换回的RGB图像') 

end

3. 基于HSI变换的融合算法：

function F=HSI_melt(HR,MS)
%调用代码------------------------------------------------------
%Image1=imread('HR.jpg');Image2=imread('MS.jpg');
%HSI_melt(Image1,Image2);
%--------------------------------------------------------------
HR=im2double(HR); [row,column,~]=size(HR);
MS=im2double(MS);
MS1=RGB2HSI(MS);     %多光谱影像转换至HSI空间
H=MS1(:,:,1); S=MS1(:,:,2); I=MS1(:,:,3);
MAX2=max(max(I));MIN2=min(min(I));
MAX1=max(max(HR));MIN1=min(min(HR));
%高分辨率影像拉与亮度分量一致,假设变换前[MIN1,MAX2]后的亮度值为[MIN2,MAX2]
A=(MAX2-MIN2)/(MAX1-MIN1);B=(MAX1*MIN2-MIN1*MAX2)/(MAX1-MIN1);
HR1=zeros(row,column);
for i=1:row
    for j=1:column
        HR1(i,j)=HR(i,j)*A+B;
    end
end

MS2=cat(3,H,S,HR1);
Image=HSI2RGB(MS2);
figure,imshow(Image);
title('基于HSI变换的影像融合结果');
end

测试：