Codes for visual shape perception and the contribution of depth information

视觉形状感知是与我们的环境有效互动和识别物体的基础。这项建议是我们正在进行的长期项目的一部分，该项目旨在揭示人类视觉系统如何处理和表示形状信息。我们以前的研究表明，简单形状的知觉涉及两种表征形式(或代码)。一种是基于全局形状特征，如纵横比、曲率或对称性。另一种是基于对象的可见表面，这些表面由对象的边缘分隔。这项提案的两个主要目标与这些准则有关。具体地说，我们希望确定对于各种全局形状属性，它们的表示是否对深度旋转不变，如果是，支持这种不变性所需的深度信息是什么。关于表面代码，拟议的实验将检查它与完全依赖于其边缘的形状表示有多大程度的不同，以及它是否对图像平面上的旋转和深度不变。这项提议的第三个主要目标是探索复杂物体的感知和表征，即那些可以被分割成两个或更多部分的物体。我们之前对复杂物体的研究表明，它们的感知涉及两种不同的机制，一种与部件的形状有关，另一种与部件的空间排列或构型有关。我们现在建议检查复杂对象中的零件表示是否使用我们为简单对象演示的相同的全局特征和曲面代码。我们还将研究对复杂物体的构型的感知。具体地说，我们将研究使感知配置或多或少困难的对象的属性，以及影响我们根据对象的配置区分对象的能力的因素。

Visual shape perception is fundamental for effective interactions with our environment and to recognize objects. This proposal is part of our ongoing long-term project of uncovering how the human visual system processes and represents shape information. Our previous studies have shown that two representation formats (or codes) are involved in the perception of simple shapes. One is based on global shape features such as aspect ratio, curvature, or symmetry. Another is based on the visible surfaces of the object that are delimited by its edges. Two main goals of this proposal concern these codes. Specifically, we wish to establish, for a variety of global shape properties, whether their representation is invariant to depth rotations and if so, what is the depth information required to support this invariance. Regarding the surface code, the proposed experiments will examine to what degree it is distinct from a representation of shape that exclusively rests on its edges, and whether it is invariant to rotations on the picture plane and in depth. A third main goal of this proposal is to explore the perception and representation of complex objects; i.e. those that can be segmented in two or more parts. Our previous investigation of complex objects has shown that their perception involves two separate mechanisms, one concerned with the shape of parts and another with their spatial arrangement, or configuration. We now propose to examine whether the representation of parts in complex objects uses the same global feature and surface codes we have demonstrated for simple objects. We will also examine the perception of the configuration of complex objects. Specifically, we will examine the properties of objects that make the perception of configuration more or less difficult as well as the factors that affect our capacity to discriminate objects on their configuration.