Bowns L
School of Psychology, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
Vision Res. 2002 Jun;42(13):1671-81. doi: 10.1016/s0042-6989(02)00081-0.
Current "spatio-temporal energy" models of how we perceive pattern motion have been very successful in helping us to understand the mechanisms of motion perception. Although they have been supported by a large number of physiological and psychological studies, they have so far not provided a complete explanation for a number of results. These results emerge from experiments concerned with predicting perceived motion direction from patterns comprising two or more components. It has been suggested that these results are more consistent with an earlier type of model based on the motion of two-dimensional features. This paper briefly describes how three generic spatio-temporal energy models have been extended to predict motion derived from two-component stimuli. A new model is then presented that utilises similar architecture to the two-stage spatial-temporal energy model proposed by Adelson and Movshon (Nature 300 (1982) 523). The first stage is a spatial temporal filtering stage and the second stage computes the intersection of constraints (IOC), an important constraint used in combining motion information across two or more components. In the model presented here the second stage is different. A directional spatial second derivative is used to extract zero-crossings at the component level, i.e. gratings. If any zero-crossing falls in the same spatial position for two or more components its displacement is tracked using a nearest neighbour match. Tracking these 'intersecting zero-crossings' essentially computes the IOC but also provides other properties that predict non-IOC motion, and second-order component motion. Surprising new insights are described into how current spatio-temporal energy models may also account for these results. However, unlike the model presented here, they rely on operations carried out on the two-dimensional pattern.
当前关于我们如何感知模式运动的“时空能量”模型，在帮助我们理解运动感知机制方面非常成功。尽管它们得到了大量生理和心理学研究的支持，但到目前为止，它们尚未对一些结果提供完整的解释。这些结果来自于一些实验，这些实验涉及从包含两个或更多成分的模式中预测感知到的运动方向。有人认为，这些结果与基于二维特征运动的早期模型类型更为一致。本文简要描述了三种通用的时空能量模型是如何扩展以预测由双成分刺激产生的运动的。然后提出了一个新模型，该模型采用了与阿德尔森和莫夫尚（《自然》300 (1982) 523）提出的两阶段时空能量模型相似的架构。第一阶段是时空滤波阶段，第二阶段计算约束交集（IOC），这是在组合两个或更多成分的运动信息时使用的一个重要约束。在这里提出的模型中，第二阶段有所不同。使用方向空间二阶导数在成分级别（即光栅）提取过零点。如果两个或更多成分的任何过零点落在相同的空间位置，则使用最近邻匹配跟踪其位移。跟踪这些“相交过零点”本质上计算了IOC，但也提供了预测非IOC运动和二阶成分运动的其他属性。文中描述了关于当前时空能量模型如何也能解释这些结果的惊人新见解。然而，与这里提出的模型不同，它们依赖于在二维模式上进行的操作。
