Brinkworth Russell S A, Mah Eng-Leng, Gray Jodi P, O'Carroll David C
Discipline of Physiology, School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SA, Australia.
J Vis. 2008 Aug 22;8(11):8.1-17. doi: 10.1167/8.11.8.
Target detection amidst clutter is a challenging task for both natural and artificial vision, yet one solved at the level of neurons in the 3rd optic ganglion of insects. These neurons are capable of responding to the motion of small objects, even against complex moving backgrounds. While the basic physiology has been investigated, little is known about how these cells are able to reject background motion while robustly responding to such small stimuli. By recording intracellularly from fly photoreceptors stimulated with natural image sequences containing a target viewed against a complex moving background, we show that the process of target detection begins at the earliest stages of vision. The temporal processing by photoreceptors alone, in the absence of any spatial interactions, improved the discrimination of targets (essentially a spatial task) by around 70%. This enhancement of target salience can be explained by elaborate models of photoreceptor temporal non-linear dynamics. The application of the functional principals outlined in this work could be utilized in areas such as robotics and surveillance, medical imaging, or astronomy, anywhere it is necessary to detect a small item from a cluttered surround.
在杂乱环境中进行目标检测，无论是对于自然视觉还是人工视觉而言，都是一项具有挑战性的任务，但昆虫第三视觉神经节中的神经元却能解决这一问题。这些神经元能够对小物体的运动做出反应，即使是在复杂的移动背景下。虽然其基本生理学特性已得到研究，但对于这些细胞如何在强烈响应此类小刺激的同时排除背景运动，我们却知之甚少。通过对果蝇光感受器进行细胞内记录，这些光感受器受到包含在复杂移动背景下观察到的目标的自然图像序列刺激，我们发现目标检测过程始于视觉的最早阶段。仅光感受器的时间处理，在没有任何空间相互作用的情况下，就能将目标辨别（本质上是一项空间任务）提高约70%。这种目标显著性的增强可以通过光感受器时间非线性动力学的精细模型来解释。这项工作中概述的功能原理的应用可用于机器人技术、监视、医学成像或天文学等领域，即在任何需要从杂乱背景中检测小物体的地方。
