Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada.
Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB, Canada.
Disabil Rehabil Assist Technol. 2021 Oct;16(7):769-779. doi: 10.1080/17483107.2020.1729874. Epub 2020 Feb 26.
Eye gaze interfaces have been used by people with severe physical impairment to interact with various assistive technologies. If used to control robots, it would be beneficial if individuals could gaze directly at targets in the physical environment rather than have to switch their gaze between a screen with representations of robot commands and the physical environment to see the response of their selection. By using a homogeneous transformation technique, eye gaze coordinates can be mapped between the reference coordinate frame of eye tracker and the coordinate frame of objects in the physical environment. Feedback about where the eye tracker has determined the eye gaze is fixated is needed so users can select targets more accurately. Screen-based assistive technologies can use visual feedback, but in a physical environment, other forms of feedback need to be examined.
In this study, an eye gaze system with different feedback conditions (i.e., visual, auditory, vibrotactile, and no-feedback) was tested when participants received visual feedback on a display (on-screen) and when looking directly at the physical environment (off-screen). Target selection tasks in both screen conditions were performed by ten non-disabled adults, three non-disabled children, and two adults and one child with cerebral palsy.
Tasks performed with gaze fixation feedback modalities were accomplished faster and with higher success than tasks performed without feedback, and similar results were observed in both screen conditions. No significant difference was observed in performance across the feedback modalities, but participants had personal preferences.
The homogeneous transformation technique enabled the use of a stationary eye tracker to select target objects in the physical environment, and auditory and vibrotactile feedback enabled participants to be more accurate selecting targets than without it.Implications for RehabilitationBeing able to select target objects in the physical environment by eye gaze could make it easier for children with disabilities to control assistive robots, because in this way they do not have to change their focus between a computer screen with commands and the robot.Providing auditory or vibrotactile feedback when using an eye gaze system made it faster and easier to know if a target was being gazed upon.Being able to select targets in the environment using eye gaze could be beneficial for other assistive technology, too, such as destination selection for power wheelchairs.
眼动追踪界面已被严重身体残障人士用于与各种辅助技术交互。如果用于控制机器人，那么如果个体可以直接注视物理环境中的目标，而不必在带有机器人命令表示的屏幕和物理环境之间切换视线，以查看选择的响应，这将是有益的。通过使用齐次变换技术，可以在眼动追踪器的参考坐标系和物理环境中的物体坐标系之间映射眼动坐标。需要有关眼动追踪器确定注视点的位置的反馈，以便用户可以更准确地选择目标。基于屏幕的辅助技术可以使用视觉反馈，但在物理环境中，需要检查其他形式的反馈。
在这项研究中，当参与者在显示器上（屏幕上）和直接注视物理环境（屏幕外）时，测试了具有不同反馈条件（即视觉、听觉、振动触觉和无反馈）的眼动系统。在屏幕条件下，十个非残疾成年人、三个非残疾儿童和两个脑瘫成年人和一个儿童完成了目标选择任务。
使用注视固定反馈模式完成的任务比没有反馈的任务完成得更快、成功率更高，并且在两种屏幕条件下都观察到了类似的结果。在反馈模式之间，观察到的性能没有显著差异，但参与者有个人偏好。
齐次变换技术使使用固定眼动追踪器选择物理环境中的目标物体成为可能，并且听觉和振动触觉反馈使参与者比没有反馈时更准确地选择目标。
通过眼动来选择物理环境中的目标物体可以使残疾儿童更容易控制辅助机器人，因为这样他们就不必在带有命令的计算机屏幕和机器人之间改变焦点。在使用眼动系统时提供听觉或振动触觉反馈，可以更快、更容易地知道目标是否被注视。通过眼动来选择环境中的目标对于其他辅助技术也可能是有益的，例如电动轮椅的目的地选择。
