Effect of fixation positions on perception of lightness

Matteo Toscani; Matteo Valsecchi; Karl R. Gegenfurtner

doi:10.1117/12.2175673

17 March 2015 Effect of fixation positions on perception of lightness

Matteo Toscani, Matteo Valsecchi, Karl R. Gegenfurtner

Proceedings Volume 9394, Human Vision and Electronic Imaging XX; 93940R (2015) https://doi.org/10.1117/12.2175673
Event: SPIE/IS&T Electronic Imaging, 2015, San Francisco, California, United States

Abstract

Visual acuity, luminance sensitivity, contrast sensitivity, and color sensitivity are maximal in the fovea and decrease with retinal eccentricity. Therefore every scene is perceived by integrating the small, high resolution samples collected by moving the eyes around. Moreover, when viewing ambiguous figures the fixated position influences the dominance of the possible percepts. Therefore fixations could serve as a selection mechanism whose function is not confined to finely resolve the selected detail of the scene. Here this hypothesis is tested in the lightness perception domain. In a first series of experiments we demonstrated that when observers matched the color of natural objects they based their lightness judgments on objects’ brightest parts. During this task the observers tended to fixate points with above average luminance, suggesting a relationship between perception and fixations that we causally proved using a gaze contingent display in a subsequent experiment. Simulations with rendered physical lighting show that higher values in an object’s luminance distribution are particularly informative about reflectance. In a second series of experiments we considered a high level strategy that the visual system uses to segment the visual scene in a layered representation. We demonstrated that eye movement sampling mediates between the layer segregation and its effects on lightness perception. Together these studies show that eye fixations are partially responsible for the selection of information from a scene that allows the visual system to estimate the reflectance of a surface.

Citation Download Citation

Matteo Toscani, Matteo Valsecchi, and Karl R. Gegenfurtner "Effect of fixation positions on perception of lightness", Proc. SPIE 9394, Human Vision and Electronic Imaging XX, 93940R (17 March 2015); https://doi.org/10.1117/12.2175673

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available