Assessing the effects of dynamic luminance contrast noise masking on a color discrimination task

The aim of this work was to assess the influence of dynamic luminance contrast noise masking (LCNM) on color discrimination for color normal and anomalous trichromats. The stimulus was a colored target on a background presented on a calibrated CRT display. In the static LCNM condition, the background and target consisted of packed circles with variable size and static random luminance. In the dynamic LCNM condition, a 10 Hz square luminance signal was added to each circle. The phase of this signal was randomized across circles. Discrimination thresholds were estimated along 20 hue directions concurrent at the color of the background. Six observers with normal colorvision, six deuter anomalous observers, and three prot anomalous observers performed the test in both conditions. With dynamic LCNM, thresholds were significantly lower for anomalous observers but not for normal observers, suggesting a facilitation effect of the masking for anomalous trichromats.Centro de Física of Minho University; Departamento de Física of University of Beira Interior; FEDER through the COMPETE Program; Foundation for Science and Technology (FCT) (PTDC/MHC-PCN/4731/2012).This work was supported by the Departamento de Física of University of Beira Interior, by the Centro de Física of Minho University, by FEDER through the COMPETE Program, and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the project PTDC/MHC-PCN/4731/2012