Investigating shape representation using sensitivity to part- and axis-based transformations.
Investigating shape representation using sensitivity to part- and axis-based transformations.
复制标题
DOI：
10.1016/j.visres.2015.07.004
复制
发表时间：
2016-09
期刊：
影响因子：
1.8
通讯作者：
Singh M
中科院分区：
文献类型：
--
作者：
Denisova K;Feldman J;Su X;Singh M
基于零件和基于轴的方法根据简单零件及其空间关系来组织形状表示。改变质量部件结构的形状变换已被证明比那些保留它的形状变换更容易检测。我们比较了对各种变换的敏感性，这些变换改变了零件的数量属性及其空间关系，同时保留了定性的零件结构。将涉及长度、宽度、曲率、方向和位置变化的形状变换应用于连接到两部分形状的较大底部的小部分。使用2IFC程序对每个转换的增量阈值进行估计。阈值被转换为形状差异的通用单位，以实现跨变换的比较。与涉及两个部分之间的空间关系(相对方位和位置)的转换相比，涉及单个部分的参数(长度、宽度、曲率)的转换具有更高的敏感度，这表明单个部分的优势效应。此外，对部分位置变化的敏感度一直是最差的--这是一种生物力学上不可信的形状转换。通过对图形和背景的立体操作，研究了基于区域的几何图形的影响。对涉及方向或位置改变的转换的正性部分(突起)和负性部分(凹痕)的敏感性进行了比较。对于部分方向的改变(生物力学上可信的)，阳性部分的敏感性好于阴性部分；而对于部分位置的改变(生物力学上不可信)，没有观察到系统性差异。
Part -and axis-based approaches organize shape representations in terms of simple parts and their spatial relationships. Shape transformations that alter qualitative part structure have been shown to be more detectable than those that preserve it. We compared sensitivity to various transformations that change quantitative properties of parts and their spatial relationships, while preserving qualitative part structure. Shape transformations involving changes in length, width, curvature, orientation and location were applied to a small part attached to a larger base of a two-part shape. Increment thresholds were estimated for each transformation using a 2IFC procedure. Thresholds were converted into common units of shape difference to enable comparisons across transformations. Higher sensitivity was consistently found for transformations involving a parameter of a single part (length, width, curvature) than those involving spatial relations between two parts (relative orientation and location), suggesting a single-part superiority effect. Moreover, sensitivity to shifts in part location—a biomechanically implausible shape transformation—was consistently poorest. The influence of region-based geometry was investigated via stereoscopic manipulation of figure and ground. Sensitivity was compared across positive parts (protrusions) and negative parts (indentations) for transformations involving a change in orientation or location. For changes in part orientation (biomechanically plausible), sensitivity was better for positive than negative parts; whereas for changes in part location (biomechanically implausible), no systematic difference was observed.