| Abstract [eng] |
In the complex situations, targets in motion are often occluded by other objects. When the retinal information cannot be obtained only prediction of object motion permits tracking the target and overcoming occlusions in its trajectory. It has already been researched that oculomotor system allows us to predict both position and velocity of occluded target for several tens of milliseconds. When this period of time elapses the eye velocity begins exponentially decaying to zero when the target is not anticipated to emerge or it reaches a plateau value, when it is expected to re-emerge. There has been a lot of work researching predictive mechanisms driving smooth pursuit and saccadic response during target occlusions. These studies exercised one-dimensional and two-dimensional predictable target trajectories. It was revealed that pre-occlusion target velocity information determines plateau value to witch eye velocity decays. The post-occlusion information shows that eye velocity at target reappearance is only influenced by anticipated target velocity. In order to minimize the influence of pre- and post-occlusion target velocity information, evenly accelerated motion, or random durations of the blanking periods were exercised in further research; only predictable target trajectories were exercised. It has been proposed that tracking of both visible and invisible predictable targets has the influence of dynamic internal representation of target motion in short-term memory. The object motion anticipation permits overcoming of object occlusions in its trajectory. This research exercises non-predictable target trajectory with occlusions of 500 and 1000 ms. The LC Technologies EyeGaze System was used for recording eyesight position that reports gaze points of both eyes at 60 Hz each and stores the data in computer for analysing offline. |
