matlab颜色空间转换RGB转换到lab

function Image = rgb2lab(Image)
if size(Image,3) ~= 3
     error('im 一定要为3通道颜色图像空间');
 end
 if ~isa(Image,'double')
     Image = double(Image)/255;
 end
 
 R = invgammacorrection(Image(:,:,1));
 G = invgammacorrection(Image(:,:,2));
 B = invgammacorrection(Image(:,:,3));
 
 T = inv([3.2406,-1.5372,-0.4986;-0.9689,1.8758,0.0415;0.0557,-0.2040,1.057])
 Image(:,:,1) = T(1) * R + T(4) * G + T(7) * B %X
 Image(:,:,2) = T(2) * R + T(5) * G + T(8) * B %Y
 Image(:,:,3) = T(3) * R + T(6) * G + T(9) * B %Z
 
 WhitePoint = [0.950456,1,1.088754];
 X = Image(:,:,1)/WhitePoint(1);
 Y = Image(:,:,2)/WhitePoint(2);
 Z = Image(:,:,3)/WhitePoint(3);
 fX = f(X);
 fY = f(Y);
 fZ = f(Z);
 Image(:,:,1) = 116 * fY - 16;%L
 Image(:,:,2) = 500 * (fX - fY);
 Image(:,:,3) = 200 * (fY - fZ);
 
end

function R = invgammacorrection(Rp)
R = zeros(size(Rp));
i = (Rp <= 0.0404482362771076);
R(i) = Rp(i)/12.92;
R(~i) = real(((Rp(~i) + 0.055)/1.055).^2.4);
end

function fY = f(Y)
fY = real(Y.^(1/3));
i = (Y < 0.008856);
fY(i) = Y(i) * (841/108) + (4/29);
end

function Y = invf(fY)
fY = Fy.^3;
i = (Y < 0.008856);
Y(i) = (fY(i) - 4/29) * (108/841);
end