光标显示模式对视线交互绩效与用户体验的影响研究

The Influence of Cursor Mode on Human Performance and User Experience in Gaze Interaction

显示与反馈方式是人机交互的重要设计要素。在视线交互这种自然人机交互技术中,视线光标的呈现方式一直是研究的焦点。本研究选取基于凝视点击范式的文本输入任务,设计了2(有无视点锁定功能)×2(有无实时注视点)被试内实验,探讨光标显示模式对视线交互绩效与用户体验的影响。结果:视点锁定功能可以提升交互绩效和用户体验,有无实时注视点对交互绩效无显著影响;输入速度的提升主要在于视点锁定功能能够让被试的视线更快地转移到下一个目标上。研究结果可为视线光标的设计与应用提供借鉴。

The eye tracking technology provides a new tool to interact with computers.Using an eye tracker,the gaze direction is detected and transformed to coordinates on the screen(i.e.,gaze point).When the gaze point fixates on a target beyond dwell time,the target is selected.Because the dwell-based approach solely uses eyes to select a target,it is very useful for disabled people who do not have enough motor control abilities.However,the jittery nature of human eyes usually makes the gaze-controlled cursor unstable,which may undermine the task performance and user experience.To counteract the instability of the gaze cursor,we proposed that the gaze-lock method may better handle normal and involuntary eye movements.We also explored whether or not to present a real-time gaze cursor to users.Although researchers disagree on this issue,they shared a common notion that the gaze point is equivalent to the gaze cursor.However,in our newly proposed gaze lock method,the gaze cursor is not completely equivalent to the realtime gaze point.Thus,we explored the influence of hiding the real-time gaze point on eye-computer interaction performance on the basis of gaze lock.In a dwell-based eye typing experiment,we compared four cursor modes:the conventional gaze cursor(CC),the no cursor(NC),the gaze-lock cursor(GLC),and the gaze-lock partial cursor(GLPC),as shown in Figure 1.CC was displayed as a hollow circle and updated its position based on the gaze point directly.NC hided the visible cursor on the basis of the conventional cursor.In GLC mode,two modifications were introduced to the conventional gaze cursor.First,when the gaze cursor stayed in the target area beyond 150ms,it became locked at the target center.Second,when the gaze point fell out of the target area,the locked cursor would be unlocked when the gaze point leaves the target for a period longer than 50ms.In GLPC mode,one difference from GLC is that the displayed gaze cursor appears at the target center only when it is locked and disappears when it is unlocked.Twenty adults(including 3 females)were recruited,all of them were experienced computer users and were familiar with Chinese Pinyin.The experimental task was to type the“#”symbol and subsequent Pinyin,ignoring the case,as shown in Figure 2.The participant began a practice session and subsequently performed a formal test session.Both the practice and test sessions included 4 blocks corresponding to 4 experimental conditions.For each participant,80 trials were collected in total.The results showed that the gaze-lock method significantly improved the typing speed(p<.001)while keeping the error rate at a very low level,the presence of a real-time gaze cursor had no significant impact on input performance(p>.05).Moreover,the gaze-lock method(p<.001)and the presence of real-time gaze cursor(p=.001)significantly reduced the gaze shift time,but both had no significant effect on the gaze focus time.Finally,GLC,followed by GLPC,was most preferred by the participants compared to NC and CC.In summary,our findings demonstrate that the gaze-lock method can improve human performance and user experience in eye typing tasks,and have potentials to be used in other dwell-based gaze interactions.