Low rank approximation of grayscale image based on SVD
Eckhart, University of Chicago

Reading RGB Image	Original Grayscale Image A=A(480) 480 by 640 matrix, rank(A)=480
A(10): the best approximation by matirices of rank 10	A(40): the best approximation by matirices of rank 40
A(70): the best approximation by matirices of rank 70	A(100): the best approximation by matirices of rank 100