Wang Xiaoye Michael, Troje Nikolaus F
Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, Ontario, Canada.
BioMotionLab, Centre for Vision Research and Department of Biology, York University, Toronto, Ontario, Canada.
J Vis. 2024 Dec 2;24(13):7. doi: 10.1167/jov.24.13.7.
Traditionally, perceptual spaces are defined by the medium through which the visual environment is conveyed (e.g., in a physical environment, through a picture, or on a screen). This approach overlooks the distinct contributions of different types of visual information, such as binocular disparity and motion parallax, that transform different visual environments to yield different perceptual spaces. The current study proposes a new approach to describe different perceptual spaces based on different visual information. A geometrical model was developed to delineate the transformations imposed by binocular disparity and motion parallax, including (a) a relief depth scaling along the observer's line of sight and (b) pictorial distortions that rotate the entire perceptual space, as well as the invariant properties after these transformations, including distance, three-dimensional shape, and allocentric direction. The model was fitted to the behavioral results from two experiments, wherein the participants rotated a human figure to point at different targets in virtual reality. The pointer was displayed on a virtual frame that could differentially manipulate the availability of binocular disparity and motion parallax. The model fitted the behavioral results well, and model comparisons validated the relief scaling in the form of depth expansion and the pictorial distortions in the form of an isotropic rotation. Fitted parameters showed that binocular disparity renders distance invariant but also introduces relief depth expansion to three-dimensional objects, whereas motion parallax keeps allocentric direction invariant. We discuss the implications of the mediating effects of binocular disparity and motion parallax when connecting different perceptual spaces.
传统上，感知空间是由视觉环境所通过的媒介来定义的（例如，在物理环境中，通过图片或在屏幕上）。这种方法忽略了不同类型视觉信息的独特贡献，比如双眼视差和运动视差，它们会变换不同的视觉环境以产生不同的感知空间。当前的研究提出了一种基于不同视觉信息来描述不同感知空间的新方法。开发了一个几何模型来描绘由双眼视差和运动视差所施加的变换，包括（a）沿着观察者视线的浮雕深度缩放，以及（b）使整个感知空间旋转的图像扭曲，还有这些变换后的不变属性，包括距离、三维形状和空间方向。该模型与两项实验的行为结果相拟合，在这两项实验中，参与者在虚拟现实中旋转一个人体模型以指向不同目标。指针显示在一个虚拟框架上，该框架可以不同程度地操控双眼视差和运动视差的可用性。该模型很好地拟合了行为结果，并且模型比较验证了以深度扩展形式存在的浮雕缩放以及以各向同性旋转形式存在的图像扭曲。拟合参数表明，双眼视差使距离不变，但也会给三维物体引入浮雕深度扩展，而运动视差则使空间方向不变。我们讨论了在连接不同感知空间时双眼视差和运动视差的中介作用的含义。
