Dataset and stimuli: "Importance of hue: color discrimination of three-dimensional objects and two-dimensional discs"

This dataset contains observer data and stimulus information for the below publication. Refer to this manuscript for more details. Please cite this manuscript if you choose to use any portion of this dataset.

Laysa Hedjar, Matteo Toscani, and Karl R. Gegenfurtner, "The importance of hue: color discrimination of three-dimensional objects and two-dimensional discs," Journal of the Optical Society of American A 42(5), 1-9 (2025), doi:10.1364/JOSAA.544380

Experimental participant data is available in thresholds.csv: 

• ptID: participant ID number
• JND (DT units): just-noticable difference threshold in detection threshold units
• stimulus type: 3D blob stimulus or 2D disc stimulus
• quadrant: quadrant of DKL color space
• color dimension: dimension of color difference (hue or chroma)
• direction: direction of color difference (increasing or decreasing for chroma, clockwise [cw] or counter-clockwise [ccw] for hue)

Participant data used to scale DKL color space is available in detection_thresholds.csv:

• ptID: participant ID number
• JND (arbitrary DKL units): just-noticable detection threshold
• angle: angle measured in DKL color space (Angle 0 is the positive L-M axis, Angle 90 is the positive S-(L+M) axis)

Stimuli (blob only) are available in stimImages.mat. None of the stimuli are gamma-corrected.

• rooms.empty: 5000 x 1000 x 3 single; image presented between 3D blob trials
• rooms.empty_shadow: 5000 x 1000 x 3 single; base image on which stimuli were pasted
• blobs: 400 x 250 x 3 x 31 x 2 x 4 x 4 x 4 single; blob stimuli used in experiment
  • blobs(:, :, :, iShift, iHC, iQuad, iPos, iRot), where:
    • iShift indexes equally spaced shifts in DKL of the odd disc relative to the reference color. Values 1-15 approach the reference from one direction (ex. decreasing chroma), value 16 is the reference color, and values 17-31 move away from the reference in the opposite direction (ex. increasing chroma).
    • iHC: 1 = hue shift, 2 = chroma shift
    • iQuad: quadrant in DKL space; 1 = +(S-LM), +LM (purplish); 2 = +(S-LM), -LM (bluish); 3 = -(S-LM), -LM (greenish); 4 = -(S-LM), +LM (orangish)
    • iPos: position of odd disc in layout (counterclockwise)
    • iRot: one of four sets of blob rotations
  • Each of these stimulus images should replace the base image at the following base image pixel locations:
    • Y: 101:500
    • X: 376:625