%将RGB图像转换为HSI图像

% 显示HSI图像

%直方图均衡化HSI图像

%将HSI图像转换回RGB图像

function rgbtohsi(x)

F=imread(x);

F=im2double(F);

r=F(:,:,1);

g=F(:,:,2);

b=F(:,:,3);

th=acos((0.5*((r-g)+(r-b)))./((sqrt((r-g).^2+(r-b).*(g-b)))+eps));

H=th;

H(b>g)=2*pi-H(b>g);

H=H/(2*pi);

S=1-3.*(min(min(r,g),b))./(r+g+b+eps);

I=(r+g+b)/3;

hsi=cat(3,H,S,I);

HE=H*2*pi;

HE=histeq(HE);

HE=HE/(2*pi);

SE=histeq(S);

IE=histeq(I);

choice=input('1:RGB 转换为 HSI\n2:显示HSI图像\n3:HSI转换为RGB图像\n4:色调均衡\n5:饱和度均衡\n6:亮度均衡 \n7:HSI均衡\n 输入您的选择 :');

switch choice

case 1

figure,imshow(F),title('RGB 图像');

figure, imshow(hsi),title('HSI 图像');

case 2

figure,imshow(F),title('RGB 图像');

figure, imshow(H),title('Hue 图像');

figure, imshow(S),title('饱和度图像');

figure, imshow(I),title('亮度图像');

case 3

C=hsitorgb(hsi);

figure,imshow(hsi),title('HSI 图像');

figure, imshow(C),title('RGB 图像');

case 4

RV=cat(3,HE,S,I);

C=hsitorgb(RV);

figure,imshow(hsi),title('HSI 图像');

figure,imshow(F),title('RGB 图像');

figure, imshow(C),title('RGB Image-Hue Equalized');

case 5

RV=cat(3,H,SE,I);

C=hsitorgb(RV);

figure,imshow(hsi),title('HSI 图像');

figure,imshow(F),title('RGB 图像');

figure, imshow(C),title('RGB 饱和度均衡');

case 6

RV=cat(3,H,S,IE);

C=hsitorgb(RV);

figure,imshow(hsi),title('HSI 图像');

figure,imshow(F),title('RGB 图像');

figure, imshow(C),title('RGB 亮度均衡');

case 7

RV=cat(3,HE,SE,IE);

C=hsitorgb(RV);

figure,imshow(hsi),title('HSI 图像');

figure,imshow(F),title('RGB 图像');

figure, imshow(C),title('RGB HSI 均衡');

otherwise

display('选择错误');

end

end

%函数，将HSI图像转换为RGB图像

function C=hsitorgb(hsi)

HV=hsi(:,:,1)*2*pi;

SV=hsi(:,:,2);

IV=hsi(:,:,3);

R=zeros(size(HV));

G=zeros(size(HV));

B=zeros(size(HV));

%RG Sector

id=find((0<=HV)& (HV<2*pi/3));

B(id)=IV(id).*(1-SV(id));

R(id)=IV(id).*(1+SV(id).*cos(HV(id))./cos(pi/3-HV(id)));

G(id)=3*IV(id)-(R(id)+B(id));

%BG Sector

id=find((2*pi/3<=HV)& (HV<4*pi/3));

R(id)=IV(id).*(1-SV(id));

G(id)=IV(id).*(1+SV(id).*cos(HV(id)-2*pi/3)./cos(pi-HV(id)));

B(id)=3*IV(id)-(R(id)+G(id));

%BR Sector

id=find((4*pi/3<=HV)& (HV<2*pi));

G(id)=IV(id).*(1-SV(id));

B(id)=IV(id).*(1+SV(id).*cos(HV(id)-4*pi/3)./cos(5*pi/3-HV(id)));

R(id)=3*IV(id)-(G(id)+B(id));

C=cat(3,R,G,B);

C=max(min(C,1),0);

end