Determination of image quality for added noise as a function of spatial frequency

The noise in color images which is referred to as chromatic noise represents a distribution within three spectral bands and contributes to chromatic and achromatic visual effects. The chromatic noise depends very strongly on the spatial frequency response of the visual system. Therefore, this study characterizes the variation in perceived chromatic noise level and generates the noise field to add to the color image samples. From these degraded images, we found that noise in low spatial frequencies is much more disturbing than in the medium and high spatial frequency regions. The perceived quality scales of the modulated chromatic noise images were compared to the subjective quality factor (S.Q.F.) scales. By using category analysis, this quality scale yields the S.Q.F. rating, and determines the dependence of the spatial frequency content of chromatic noise and achromatic effect