Spatial structure, phase, and the contrast of natural images.
J Vis
; 22(1): 4, 2022 01 04.
Article
in En
| MEDLINE
| ID: mdl-35006237
ABSTRACT
The sensitivity of the human visual system is thought to be shaped by environmental statistics. A major endeavor in vision science, therefore, is to uncover the image statistics that predict perceptual and cognitive function. When searching for targets in natural images, for example, it has recently been proposed that target detection is inversely related to the spatial similarity of the target to its local background. We tested this hypothesis by measuring observers' sensitivity to targets that were blended with natural image backgrounds. Targets were designed to have a spatial structure that was either similar or dissimilar to the background. Contrary to masking from similarity, we found that observers were most sensitive to targets that were most similar to their backgrounds. We hypothesized that a coincidence of phase alignment between target and background results in a local contrast signal that facilitates detection when target-background similarity is high. We confirmed this prediction in a second experiment. Indeed, we show that, by solely manipulating the phase of a target relative to its background, the target can be rendered easily visible or undetectable. Our study thus reveals that, in addition to its structural similarity, the phase of the target relative to the background must be considered when predicting detection sensitivity in natural images.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Vision, Ocular
/
Contrast Sensitivity
Limits:
Humans
Language:
En
Journal:
J Vis
Journal subject:
OFTALMOLOGIA
Year:
2022
Type:
Article
Affiliation country:
Australia