Integration of elementary features in texture perception

特征整合及其在图形-背景分离中的作用是视觉感知的一个关键问题。 根据已建立的观点，早期retinotopic阶段（V1，V2）服务于局部特征分析，而形状检测和对象识别位于更高的腹侧区域，其以特征和视图独立的方式处理对象。与早期通道-后来的整合帐户之间的方向和空间frequency. Texture形状的强烈的线索组合效应（“协同”）被发现时，更好地检测在Gabor随机场的方向和空间频率的特征对比度时，然而，只有当他们几乎是由一个功能单独可见，只有当Gabor元素形成一个明确的2D形状。EEG记录显示，在下颞区（TP）周围的电极上，双线索目标在130 ms时开始出现长期持续的负电位，而目前还没有中央枕叶（OZ）电极上双线索相关的独特证据，这表明在后来的形状处理区域进行了功能整合。 最近，使用带宽调制纹理重新审视了协同效应。作者发现，从多个尺度和方向计算的低水平汇总统计量净对比能量解释了协同效应。这一发现挑战了一个晚，基于形状的帐户功能集成。在这个项目中，我们重新处理的纹理感知中的空间亮度分布在傅立叶意义上的基本特征（方向，空间尺度和亮度）的特征协同效应的起源。首先，我们试图建立强大的线索组合效果的纹理图检测完全捕获的本地能量计算。其次，我们解开纹理图检测形状歧视专用的实验设计，并探讨是否线索求和方案中发现的形状识别任务中发现的规则不同的检测任务。第三，EEG记录将通过源建模技术进行分析，以区分源自初级视觉皮层和腹侧处理流的活动。应用专门的设计和任务，解开检测和形状歧视，这将揭示的时间过程和神经相关的线索总和在两个主要的处理区域纹理和形状。

Feature integration and its role in figure-ground segregation is a key problem of visual perception. According to established views, early retinotopic stages (V1, V2) serve local feature analysis, while shape detection and object recognition are located at higher ventral areas, which process objects in a feature and view independent manner. In line with an early channeling – later integration account strong cue combination effects (“synergy”) among orientation and spatial frequency were found. Texture shapes were much better detectable in Gabor random fields when there was feature contrast in both orientation and spatial frequency, however, only when they were barely visible by one feature alone and only when the Gabor elements formed a definite 2D shape. EEG recordings revealed a long-lasting negative potential starting at 130 ms specific for double-cue targets at electrodes around the inferior temporal region (TP), while there currently is no unique evidence for a double-cue correlate at central occipital (OZ) electrodes, suggesting feature integration at later shape-processing areas. Recently, the synergy effect was revisited using bandwidth modulated textures. Authors found that a low-level summary statistic, net contrast energy, computed from multiple scales and orientations, explains the synergy effect. The findings challenge a late, shape-based account of feature integration. In this project we readdress the origin of the feature synergy effect for the essential features of spatial luminance distributions in a Fourier sense (orientation, spatial scale and luminance) in texture perception. First, we try to establish that the strong cue combination effects in texture figure detection are fully captured by local energy computations. Second, we disentangle texture figure detection from shape discrimination with dedicated experimental designs, and explore whether the cue summation schemes found in shape identification tasks differ from the rules found in detection tasks. Third, EEG recordings will be analyzed by source modeling techniques to distinguish between activity originating in the primary visual cortex and the ventral processing stream. Applied with dedicated designs and tasks which disentangle detection and shape discrimination this will shed light on the time-course and neural correlates of cue summation in the two major processing regions for textures and shapes.