电子科发女学光电科学与工程学院 SCHOOL OF OPTOELECTRONIC SCIENCE AND ENGINEERING OF UESTC 5.Fidelity Criteria A closely related objective fidelity criterion is the mean square signal to noise ratio of the compressed-decompressed image M-1N-1 ∑∑fx,y SNRms x=0y=0 M-1N-1 ∑∑[f(xy)-f(x,y] x=01y=0 A closely related objective fidelity criterion is the mean square signal to noise ratio of the compressed-decompressed image 2 1 0 1 0 2 1 0 1 0 [ ( , ) ( , )] ( , ) f x y f x y f x y SNR M x N y M x N y ms               5. Fidelity Criteria