Development of Cueing Algorithm Based on “Closed-Loop” Control for Flight Simulator Motion System

The classical washout algorithm had fixed gains and manually constructed filters, so that it led to poor adaptability. Furthermore, it lost the sustained acceleration cues of high-and mid-frequency in cross-over(tilt-coordination) channel, and the acceleration of cross-over frequency was also limited by angular velocity limiter, so the false cues in flight simulation process were clearly perceived by pilots. The paper studied the characteristics of the classical washout algorithm and flight simulator motion platform, tried to redesign the source of cross-over acceleration channel and translation acceleration channel, and transferred the part of cross-over acceleration that was unsimulated sustained acceleration to translation acceleration channel. Comparisons were mainly made between classical washout algorithm and revised algorithm in a longitudinal/pitch direction. The evaluation was based on the implementation of human vestibular perception system. The results demonstrated that the revised algorithm could significantly reduce the phase lag, and improved the spikes tracking performance. Furthermore, sensory angular velocity and the error of sensory acceleration were strictly controlled within the threshold of human perception system, and the displacement was a little broader than the classical washout algorithm. Therefore, it was proved that the new algorithm could diminish the filters parameters and heighten the self-adaptability for the washout algorithm. In addition, the magnitude of false cues was remarkably reduced during flight simulator, and the workspace utilization of the motion platform was developed by "closed-loop" control system.     

Motion speed modulates walking direction discrimination: The role of the feet in biological motion perception

The human visual system is tuned to the motions of biological entities, which provide potentially vital information for survival. The current study examines the interplay between motion speed and motion direction perception. Following a brief presentation of a point-light walker walking straight ahead or slightly leftward or rightward, observers were asked to quickly judge the walking direction (left or right). Participants showed better direction discrimination when the walker walked at a fast pace compared to a natural or slow pace, and this was not simply due to a difference in motion cycles. Moreover, walking direction sensitivity could be enhanced by increasing the feet motion speed alone, so long as the direction of feet movement was consistent with that of the other body parts. These findings demonstrate that our perception of walking direction is influenced by local motion speed, and highlight the role of the feet in biological motion perception.     

视觉运动知觉脑机制研究现状

视觉运动知觉问题在整个知觉理论中占有重要的地位,背侧和腹侧的两条视觉通道的发现可以说是近代认知神经科学的一个代表性成就,随着ERP、fMRI等无损探测技术的发展,对人类视觉运动知觉的研究也不断深入,近年来人们利用脑信息学方法。对视觉运动知觉进行了系统的研究,其研究结论将对建立人工智能系统产生深远的影响。     

基于多粒度感知SVM的复杂场景人车分类方法

针对复杂场景中的人车分类问题, 提出一种基于多粒度感知SVM (support vector machine)的复杂场景人车分类方法。该方法首先对视频场景进行运动区域分析, 结合角点检测方法提取运动区域视觉感知信息, 在时空域中采用Kalman滤波将感知信息进行关联推理, 去除噪声干扰。 再以运动区域质心点为中心, 构造目标的多粒度感知特征, 最后构造2级SVM分类器, 将目标多粒度感知特征向量集输入SVM分类器进行训练及分类, 得到人车分类结果输出。实验结果表明, 该方法取得了良好的分类效果, 人、车全天候平均分类正确率分别达到93.6%以上, 能有效避免光照、色彩、目标大小等变化导致的误分类问题, 适用于智能交通视频的人车分类应用。     

Hysteresis in the perception of motion direction as evidence for neural cooperativity

When elements of a parallel network, such as the human brain, are extensively interconnected, the network can exhibit 'cooperative behaviour'. Such behaviour, which is characterized by order-disorder transitions, multi-stable states, and a form of memory called 'hysteresis', has been observed in human stereopsis and has motivated models of stereopsis that incorporate cooperative networks. More recently, cooperative phenomena have also been observed in human visual motion perception. This report strongly supports a cooperative interpretation of motion perception by demonstrating hysteresis in the perception of motion direction. The results agree quantitatively with a mathematical model incorporating nonlinear excitatory and inhibitory interactions among direction-selective elements.     

基于速率的认知无线网络低复杂度宽带频谱接入算法

为解决认知无线网络中宽带频谱感知模式的计算量大和感知时间延长等问题,提出了一种基于速率的认知无线网络低复杂度宽带频谱感知算法。在宽带频谱感知的基础上,设定选择条件,对信道的期望传输速率进行比较,确定需要感知的信道,以实现减少认知无线网络次用户系统的信道感知时间和感知计算量的目标。经过仿真实验分析对比表明,该算法可以有效地平衡次用户系统吞吐量最大化和主用户系统的干扰之间的矛盾。     

Functions of the colour-opponent and broad-band channels of the visual system

The colour-opponent and broad-band channels of the primate visual system originate in the retina and remain segregated through several neural stations in the visual system. Until now inferences about their function in vision have been based primarily on studies examining single-cell receptive field properties which have shown that the colour-opponent retinal ganglion cells have small receptive fields, produce sustained responses and receive spatially segregated inputs from different cone types; the broad-band cells have large receptive fields, respond transiently and receive cone inputs that are not spatially separated. We have now examined the visual capacities of rhesus monkeys before and after interrupting either of these channels with small lesions at the lateral geniculate nucleus. Here we report that the colour-opponent channel is essential for the processing of colour, texture, fine pattern and fine stereopsis, whereas the broad-band channel is crucial for the perception of fast flicker and motion. Little or no deficits were found in brightness and coarse-shape discrimination, low spatial frequency stereopsis and contrast sensitivity after the disruption of either of the channels.     

Neural mechanisms of unconscious visual motion priming

The neural correlates of the motion priming were examined in normal young subjects using event-related brain potentials (ERPs) and functional magnetic resonance imaging (fMRI). Visual motion perception can be uncon-sciously biased in favor of a particular direction by a pre-ceding motion in that direction. Motion priming first in-volved an enhancement of ERP amplitude about 100 ms fol-lowing the onset of motion. The amplitudes of ERP compo-nents after 350 ms were also increased. The fMRI results suggest that the early-latency effect reflects modulation of neural responses in extrastriate cortex. Higher-level visual processing areas, including cortical regions MT/MST and the intraparietal cortices were also activated. The findings provide direct evidence that unconscious priming of motion perception is the result of interaction of direction-selective neural responses to motion stimuli. The results cannot be accounted for by refractoriness of neural responses, but in-stead support a theory of motion priming based on motion opponency, as proposed in computational models.     

Self-motion and the perception of stationary objects

One of the ways that we perceive shape is through seeing motion. Visual motion may be actively generated (for example, in locomotion), or passively observed. In the study of the perception of three-dimensional structure from motion, the non-moving, passive observer in an environment of moving rigid objects has been used as a substitute for an active observer moving in an environment of stationary objects; this 'rigidity hypothesis' has played a central role in computational and experimental studies of structure from motion. Here we show that this is not an adequate substitution because active and passive observers can perceive three-dimensional structure differently, despite experiencing the same visual stimulus: active observers' perception of three-dimensional structure depends on extraretinal information about their own movements. The visual system thus treats objects that are stationary (in an allocentric, earth-fixed reference frame) differently from objects that are merely rigid. These results show that action makes an important contribution to depth perception, and argue for a revision of the rigidity hypothesis to incorporate the special case of stationary objects.     

基于深度学习的手术场景运动感知

基于术中影像的运动感知是计算机辅助手术系统开发的重要研究内容,能够为运动补偿、软组织形变分析等应用提供有价值的信息,从而提高手术效率并增强手术安全。然而,手术影像中运动器械的遮挡降低了对局部区域估计的准确性。为解决这一难题,提出一种基于光流网络和解耦表示的运动感知方法,并结合自监督学习范式优化模型。制作了神经外科手术数据集,在PyTorch深度学习框架下对模型进行训练和验证。实验结果表明：该运动估计方法在复杂手术场景中具有稳定性强、准确度高的优点,在计算机辅助手术中具有较高的应用价值。