See the gallery of stimuli.
This data set was measured to demonstrate the effect of CSF flattening in complex images. Gabor patches from 4 to 16 cpd were superimposed on an actual image (portrait) in three different regions: the region with almost no masking (hair), with moderate masking (face) and with strong masking (band). The hair region has almost no masking because the pixel values are clamped at 0. Note that also the luminance varies greatly between these three regions.
The thresholds were measured in the 4-alternative-forced-choice experiment, in which all four images were shown side-by-side. The measurement procedure was the same as for the "Contrast sensitivity for wide luminance range" data set.
This is the original Visual Difference Predictor based on corresponence with the author and the book chaper: Daly, S. "The Visible Differences Predictor: An Algorithm for the Assessment of Image Fidelity." In Digital Images and Human Vision, edited by Andrew B. Watson, 179-206. MIT Press, 1993.
The metric uses the default parameters from the paper except the masking slope, set to 0.9 for all bands, which was found from fitting the metric to the masking data sets. One optional component in the VDP is computing contrast in the cortex filtered images, which could be either global or local. This version uses global contrast.
The metric also includes an improved variation of the phase uncertainty, as described in: Lukin, A. "Improved Visible Differences Predictor Using a Complex Cortex Transform." In International Conference on Computer Graphics and Vision (GraphiCon), 2009. Phase uncertainty is not mentioned in the '93 book chapter, but is described in the patent application. The method proposed by Lukin achieves the same goals as phase uncertainty but is more elegant and efficient than the approach described in the patent.