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 revision of the metric described in detail in the paper "HDR-VDP-2: A calibrated visual metric for visibility and quality predictions in all luminance conditions" (doi). It shares many similarities with VDP'93 and HDR-VDP, as it was inspired by these metrics, but the functionality is much extended and individual components are thoroughly revised. Note that the model parameters for this revision are different than the parameters included in the supplementary materials of the paper. Refer to the project web-page for the latest code and parameter values.
Revision 2.1 fixes an important bug that caused the nCSF to remain fixed below 1 cd/m^2. To extend the operational dynamic range, the CSF was measured at additional luminance level of 0.002 cd/m^2. The CSF was also measured for all observers, resulting in a more accurate CSF function fit. The predictions are improved for majority of data sets.