function [ Lab ] = XYZ2Lab( XYZ,XYZ0 )
%XYZ数据转换为Lab数据,可批量处理
%输入原始XYZ数据, n*3 矩阵
%输入使用的光源的三刺激值XYZ0,1*3矩阵
X=XYZ(:,1);
Y=XYZ(:,2);
Z=XYZ(:,3);
X0=XYZ0(:,1);
Y0=XYZ0(:,2);
Z0=XYZ0(:,3);
L=116*f(Y./Y0)-16;
a=500*(f(X./X0)-f(Y./Y0));
b=200*(f(Y./Y0)-f(Z./Z0));
Lab(:,1)=L;
Lab(:,2)=a;
Lab(:,3)=b;
function [ ff ] = f( I )
if ( I > 0.008856 )
ff =
I.^(1.0/3);
else
ff =
7.787*I+16.0/116;
end
*******************************************************************
*******************************************************************
或者:
function [ Lab ] = XYZ2Lab( XYZ, XYZ0 )
%XYZ数据转换为Lab数据,可批量处理
%输入原始XYZ数据, n*3 矩阵
%输入使用的光源的三刺激值XYZ0,1*3矩阵
X=XYZ(:,1);
Y=XYZ(:,2);
Z=XYZ(:,3);
X0=XYZ0(1);
Y0=XYZ0(2);
Z0=XYZ0(3);
f1 = f(X/X0);
f2 = f(Y/Y0);
f3 = f(Z/Z0);
j1 = find(X/X0)<=0.008856;
j2 = find(Y/Y0)<=0.008856;
j3 = find(Z/Z0)<=0.008856;
f1(j1) = ff(X(j1)/X0);
f1(j2) = ff(Y(j2)/Y0);
f1(j3) = ff(Z(j3)/Z0);
L=116*f2-16;
a=500*(f1-f2);
b=200*(f2-f3);
Lab(:,1)=L;
Lab(:,2)=a;
Lab(:,3)=b;
end
function [ ff ] = f(I)
ff =
I.^(1.0/3.0);
end
function [ ff ] = ff(I)
ff =
7.787*I+16.0/116.0;
end