Mid-level mechanisms of surface and binocular perception

描述(申请人提供)：视网膜图像本身就是支离破碎和模棱两可的，因为独立实体的图像重叠。但早期的视觉机制并不具备将重叠的2-D视网膜图像解析成不同的3-D实体的能力。解析这些图像的工作落在中间层机制上，它的主要作用是将不同的实体表示为单独的表面。然后，表示的表面信息作为输入，分别输入到我们对物体和空间的3D感知的基础上的内容和位置系统。因此，中层机制不仅是早期和晚期视觉机制之间的简单信息“管道”，而且在决定所传达的视觉信息的质量和可靠性方面起着至关重要的作用。与视觉处理的其他方面相比，人们对中层机制知之甚少。最大的挑战之一是发现通常支离破碎和模棱两可的视网膜信息是如何转化为可靠的表面表示的，大概是通过扩散操作。有时，当属于同一实体的图像由于遮挡而被分割成多个部分时，需要进行曲面内插操作以将这些部分集成到全局曲面中。此外，参与这些操作的两只眼睛的输入可能在内容和位置上不同。面对复杂的视觉输入，进一步提出，中层机制必须依赖内部假设(知觉规则)和来自较高视觉水平的反馈来指导表征表面。但这些操作是如何完成的仍不清楚。为了弥补这一缺陷，本提案使用人类心理物理学的方法，通过关注三个具体目标来研究上述问题。目标1研究扩展操作如何表示具有纹理图案的表面，这比表示无纹理的表面更复杂。提出了减少编码冗余度的原理来控制扩展输入操作，使得全局表面表示操作是有效的，但容易产生较差的分辨率。后者可能是众所周知的“拥挤效应”现象的基础之一。目的2研究纹理-曲面的插补运算。认识到注意和客体知识的作用，本研究考察了这些自上而下的因素是如何影响表面整合的。目的3研究中层机制的长期可塑性。将进行知觉学习实验，以揭示广泛的训练如何修改在中级水平实施的知觉规则。这项提议的长期目标是增进我们对视觉信息是如何由中层机制处理和呈现的知识。这些知识帮助我们更好地了解人类如何感知视觉世界，并为弱视、斜视和衰老相关的视觉功能障碍的行为诊断和治疗提供了临床基础。

DESCRIPTION (provided by applicant): Retinal images are inherently fragmentary and ambiguous because images of separate entities overlap. But the early visual mechanisms are not equipped to parse the overlapping 2-D retinal images into distinct 3-D entities. The job of parsing these images falls on the mid-level mechanisms, whose main role is to represent the distinct entities as separate surfaces. The represented surface information then serves as inputs to the WHAT and WHERE systems that underlie our 3-D perception of objects and space, respectively. As such, the mid-level mechanisms are not just simple "conduits" of information between early and late level visual mechanisms but play a crucial role in determining the quality and reliability of the visual information conveyed. Compared to other aspects of visual processing, less is known about the mid-level mechanisms. One of the biggest challenges is to discover how the often fragmentary and ambiguous retinal information is transformed into reliable surface representations, presumably, through a spreading-in operation. At times, when an image belonging to the same entity is broken into parts due to occlusion, a surface interpolation operation is required to integrate the parts into a global surface. Moreover, inputs from the two eyes that contribute to these operations can be disparate in content and location. In the face of the myriad complexities of the visual inputs, it is further proposed that the mid-level mechanisms must rely on internal assumptions (perceptual rules) and feedbacks from the higher visual levels for guidance in representing surfaces. But how these operations are accomplished is still unclear. Remedying it, this proposal uses the human psychophysical approach to investigate the above issues by focusing on three specific aims. Aim 1 investigates how the spreading-in operation represents surfaces with texture patterns, which is more complex than representing texture-free surfaces. It is proposed the principle of reducing coding redundancy that governs the spreading-in operation causes the global surface representation operation to be efficient but prone to poor resolution. The latter could be one basis of the well-known "crowding effect" phenomenon. Aim 2 investigates the texture-surface interpolation operation. Cognizant of the roles of attention and object knowledge, the research investigates how these top-down factors influence surface integration. Aim 3 investigates the long-term plasticity of the mid-level mechanisms. Perceptual learning experiments will be conducted to reveal how extensive training modifies the perceptual rules implemented at the mid-level. The long-term goal of this proposal is to advance our knowledge of how visual information is processed and represented by the mid-level mechanisms. This knowledge helps us better understand how humans perceive the visual world, and provides a clinical basis for behavioral diagnoses and treatments of visual dysfunctions related to amblyopia, strabismus and aging.