数字图像处理 彩色空间转化 代码

function rgb = hsi2rgb(hsi) %HSI2RGB converts an HSI image to RGB % RGB = HSI2RGB(HSI) % the input image, is of class double in range[ 0 1], where: % hsi(:,:,1) = hue divided by 2*pi % hsi(:,:,2) = saturation % hsi(:,:,3) = intensity % the output image, is of class double in range[ 0 1], where: % rgb(:,:,1) = red % rgb(:,:,2) = green % rgb(:,:,3) = blue % extracts the hsi image H = hsi(:,:,1)*2*pi; S = hsi(:,:,2); I = hsi(:,:,3); %implement the conversion e.q.s 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 region (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 region (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 region (4*pi/3 <= H < 2*pi) 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)); % combine all results into a RGB image rgb = cat (3, R,G,B); rgb = max(min(rgb,1),0);