With the technology of image compression and codec booming

and in order to control the transmission of their bit-stream

the term of image quality is given a kind of new degree and challenge. Today the research of Image Quality Assessment has also become one of the basis technologies in the realm of images and information. This paper analyzed the characters of Human Visual System (HVS) at first

that included the visual nonlinear

multi-channel and masking effect as well

then constituted a kind of mathematic model to simulate the course that the human visual system proceeds the image information. In the model

original images and distorted images are transformed respectively to the perceptual field

that is

both of them are processed by the basic visual nonlinear firstly

and with that enter a band pass filter created by the modulate transform function. During the processing of the multi-channel in the HVS model

according to the characteristic of masking

the function of band pass filter is divided into five bands by the varying spatial frequency of initial image. Finally the value comes into being that we gained from the vision pathways

and then the HVS-E (Error) is obtained. The result from experiments indicates the fine agreement between the HVS-E and the MOS (mean opinion score).