function RxValue=RXAlgorithm(HyperCube)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%RX algorithm
%parameter:
%      HyperCube 輸入cube
%      RxValue rx算法得出的值，類型為double
%reference:
%      使用的為全局均值與協方差
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% HyperCube = ImageInput(0);
gray=double(HyperCube);

[m,n,l]=size(gray);
grayVector=reshape(gray,m*n,l);%row:m*n,columm:l
xMat=grayVector';%row:l,columm:m*n

Mean=mean(grayVector);

M=repmat(Mean',1,m*n);%l X mn
u=(xMat-M)*(xMat-M)'/(m*n-1);%樣本協方差陣
uInverse=inv(u);%!!
for i=1:m*n
   x=xMat(:,i);
   rxVector(i)=(x-Mean')'*uInverse*(x-Mean');
end
rx=reshape(rxVector,m,n);
RxValue=double(rx);