In projectors and head-mounted displays, an out-of-focus image appears blurred. Even when a display itself is in focus, computer operation may be hindered if the display is far from the user or if a user has poor visual acuity, because the user cannot see the screen clearly. In this study, we conducted an experiment in which participants performed a pointing task under blurred display conditions and investigated the relationship between blur strength and user performance. The results showed that movement time and error rate increased as blur became stronger, and that the effect of blur on movement time was larger when targets were smaller. We further showed that movement time can be estimated with high accuracy by a model that improves on Fitts' law. In a follow-up experiment to examine the applicability of this model, we adjusted target size for each participant and showed that the effect of blur level on movement time could be reduced. These findings suggest potential use in tools that adapt user interfaces to users' visual acuity.

翻译：在投影仪和头戴式显示器中，图像失焦会产生模糊效果。即使显示器本身处于对焦状态，若显示屏距离用户较远或用户视力不佳，因无法清晰观察屏幕，计算机操作也可能受到阻碍。本研究通过一项实验，让参与者在模糊显示条件下执行指向任务，探讨了模糊强度与用户性能之间的关系。结果表明，随着模糊程度增强，运动时间和错误率均有所上升，且当目标较小时，模糊对运动时间的影响更为显著。我们进一步证明，通过一种改进菲茨定律的模型，可以高精度地估算运动时间。在后续验证该模型适用性的实验中，我们为每位参与者调整了目标尺寸，并发现模糊级别对运动时间的影响得以降低。这些发现表明，该模型在根据用户视力状况自适应调整用户界面的工具中具有潜在应用价值。