Figure 20: Subjective ratings of perceived distortion for images containing both structural distortion and additive white noise. In each graph, the horizontal axis denotes the total RMS contrast of the combined distortions and the vertical axis denotes perceived distortion relative to the corresponding original image; error bars denote standard errors of the means. Black circles: results for and . White circles: results for and . Gray squares: results for and . White squares: results for and . Black triangles: results for and . Gray triangles: results for and . White triangles: results for and . Note that, for the image baby, the contrasts are halved. Figure from [59].