Image perceptual quality assessment is a key problem in image processing engineering.According to the perceptual characters of Human Visual System (HVS)

a Just Noticeable Distortion (JND) threshold model is constructed using contourlet transform

which can well qualify spatial frequency sensitivity

orientation sensitivity

contrast masking and neighborhood masking effects of HVS.As a result of taking account of neighborhood masking additionally

this JND model can distinguish the different masking intensity of smoothness

edge and texture domain

and implement more accurate JND threshold.Based on our JND threshold model

the perceptual error between contourlet coefficients is defined

and then a quantitative perceptual quality metric HVSNR is proposed.Experiments demonstrate that our metric can provide quality evaluation well correlated with those given by human observers.