XYZ色空間からL*a*b*色空間へ

XYZtoLab.pl

# 参考：http://www005.upp.so-net.ne.jp/fumoto/linkp25.htm
sub xyz_to_Lab {
    my $xyz_href = shift;
    my ($Xn, $Yn, $Zn) = ( 98.072, 100, 118.225);
    #my ($Xn, $Yn, $Zn) = ( 95.045, 100, 108.892);
    
    my $Lab = {
        L => 116 * ( ($xyz_href->{X} / $Yn) ** (1/3) ) - 16,
        a => 500 * ( ($xyz_href->{X} / $Xn) ** (1/3) - ($xyz_href->{Y} / $Yn) ** (1/3) ),
        b => 200 * ( ($xyz_href->{Y} / $Yn) ** (1/3) - ($xyz_href->{Z} / $Zn) ** (1/3) ),
    };
    return $Lab;
}