SD&A 2025: Convexity biases in stereoscopically viewed ground terrain (2D)

Описание: This presentation was delivered at the SD&A 2025 conference (3-6 February 2025) held in Burlingame, CA USA. For more information see: http://stereoscopic.org

Note: This is the 2D version of the presentation. For the 3D version see:    • SD&A 2025: Convexity biases in stereoscopi...  

Title: Convexity biases in stereoscopically viewed ground terrain [SDA-339]

Abstract: Judging the ‘lay of the land’ during locomotion relies on the integration of an array of perceptual and motor cues. We demonstrated that stereopsis plays a substantial role in discriminating surface perturbations of ground terrain; however, observers were often biased towards perceiving convex surfaces when shading cues were highly salient. The aim of the current study was to 1) determine if this bias is replicated under different viewing conditions, and if so, 2) to better understand the source of the phenomenon. To this end we first replicated our previous study. We then show that the convexity bias was not driven by unreliable stereoscopic cues in low illumination, but instead depended on the presence of the shading itself. We did so by varying the availability of binocular disparity by (i) only showing half of the surface binocularly or (ii) presenting the full surface to one eye and half of the surface to the other. The convexity bias only overrides stereopsis when it defines a smooth coherent surface with intense shading. Importantly, our observers possessed normal stereoacuity, yet 50% of them used an ambiguous shading cue to judge terrain. Under impoverished viewing, this could lead to potentially dangerous errors during locomotion.

Speaker: Brittney Hartle, York University (Canada)

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