%Some parts of code obtained from
%http://math.gmu.edu/~tsauer/class/447/proj/chap11.pdf

function Y = quant(X,C,Q)
X=double(X);  % convert to double
X = X - 128;  % Center pixels
Y = C*X*C';   % perform 2D-DCT
Y = round(Y./Q); % divide each value by Quantization matrix and round
Not enough input arguments.

Error in quant (line 5)
X=double(X);  % convert to double