Sikoglu Elif M, Calabro Finnegan J, Beardsley Scott A, Vaina Lucia M
Brain and Vision Research Laboratory, Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA.
Seeing Perceiving. 2010;23(3):197-221. doi: 10.1163/187847510X503605. Epub 2010 Jun 4.
Previous studies of heading perception suggest that human observers employ spatiotemporal pooling to accommodate noise in optic flow stimuli. Here, we investigated how spatial and temporal integration mechanisms are used for judgments of heading through a psychophysical experiment involving three different types of noise. Furthermore, we developed two ideal observer models to study the components of the spatial information used by observers when performing the heading task. In the psychophysical experiment, we applied three types of direction noise to optic flow stimuli to differentiate the involvement of spatial and temporal integration mechanisms. The results indicate that temporal integration mechanisms play a role in heading perception, though their contribution is weaker than that of the spatial integration mechanisms. To elucidate how observers process spatial information to extract heading from a noisy optic flow field, we compared psychophysical performance in response to random-walk direction noise with that of two ideal observer models (IOMs). One model relied on 2D screen-projected flow information (2D-IOM), while the other used environmental, i.e., 3D, flow information (3D-IOM). The results suggest that human observers compensate for the loss of information during the 2D retinal projection of the visual scene for modest amounts of noise. This suggests the likelihood of a 3D reconstruction during heading perception, which breaks down under extreme levels of noise.
以往关于航向感知的研究表明，人类观察者采用时空整合来适应光流刺激中的噪声。在此，我们通过一项涉及三种不同类型噪声的心理物理学实验，研究了空间和时间整合机制是如何用于航向判断的。此外，我们开发了两种理想观察者模型，以研究观察者在执行航向任务时所使用的空间信息成分。在心理物理学实验中，我们对光流刺激施加了三种类型的方向噪声，以区分空间和时间整合机制的参与情况。结果表明，时间整合机制在航向感知中发挥作用，但其贡献比空间整合机制的贡献要弱。为了阐明观察者如何处理空间信息以从有噪声的光流场中提取航向，我们将对随机游走方向噪声的心理物理学表现与两种理想观察者模型（IOM）进行了比较。一种模型依赖于二维屏幕投影的流信息（二维IOM），而另一种使用环境流信息，即三维流信息（三维IOM）。结果表明，对于适量的噪声，人类观察者在视觉场景的二维视网膜投影过程中会补偿信息损失。这表明在航向感知过程中存在三维重建的可能性，而在极端噪声水平下这种重建会失效。
