Perceptual dimensions underlying lightness perception in homogeneous center-surround displays

Area of Science:

• Visual Perception
• Psychophysics
• Computational Vision

Background:

• Homogeneous surrounds create a "crispening effect" in lightness perception, indicating a second perceptual dimension beyond lightness.
• Low-contrast targets in homogeneous displays are difficult to match, suggesting limitations in lightness as the sole perceptual variable.
• Existing models may not fully capture the complexity of visual targets within different surround types.

Purpose of the Study:

• To investigate if a two-dimensional model (lightness and transmittance) improves perceptual matching compared to lightness alone.
• To determine if transmittance matching is linked to perceived transparency or perceived edge contrast instructions.
• To explore the differences in perceived target-surround edge contrast between homogeneous and textured displays.

Main Methods:

• Asymmetric matching task involving homogeneous and textured/rocky displays.
• Observers adjusted lightness and transmittance of a test patch to match a target.
• Task instructions varied, focusing on matching perceived transparency or perceived edge contrast.

Main Results:

• Satisfactory matches for targets in homogeneous displays to textured displays required adjusting both lightness and transmittance.
• Observers primarily adjusted transmittance when matching perceived edge contrast against homogeneous surrounds.
• Transparency matching instructions did not lead to a primary adjustment of transmittance.

Conclusions:

• Perceived target-surround edge contrast differs significantly between homogeneous and textured visual displays.
• Transparency serves as a mid-level property in textured displays, aiding in equating target lightness and edge contrast appearance.
• A two-dimensional approach, incorporating lightness and transmittance, offers a more comprehensive understanding of visual perception in complex displays.