Screen readers are audio-based software that Blind and Low Vision (BLV) people use to interact with computing devices, such as tablets and smartphones. Although this technology has significantly improved the accessibility of touchscreen devices, the sequential nature of audio limits the bandwidth of information users can receive and process. We introduce TapNav, an adaptive spatiotactile screen reader prototype developed to interact with touchscreen interfaces spatially. TapNav's screen reader provides adaptive auditory feedback that, in combination with a tactile overlay, conveys spatial information and location of interface elements on-screen. We evaluated TapNav with 12 BLV users who interacted with TapNav to explore a data visualization and interact with a bank transactions application. Our qualitative findings show that touch points and spatially constrained navigation helped users anticipate outcomes for faster exploration, and offload cognitive load to touch. We provide design guidelines for creating tactile overlays for adaptive spatiotactile screen readers and discuss their generalizability beyond our exploratory data analysis and everyday application navigation scenarios.

翻译：屏幕阅读器是基于音频的软件，盲人及低视力（BLV）人群通过其与平板电脑和智能手机等计算设备进行交互。尽管该技术显著提升了触摸屏设备的可访问性，但音频的序列性本质限制了用户接收和处理信息的带宽。我们提出TapNav——一种为空间化交互触摸屏界面而开发的自适应空间触觉屏幕阅读器原型。TapNav的屏幕阅读器提供自适应听觉反馈，结合触觉覆盖层共同传递界面元素在屏幕上的空间信息与位置。我们邀请12位BLV用户对TapNav进行评估，通过该原型探索数据可视化界面并操作银行交易应用。定性研究结果表明，触点和空间约束导航能帮助用户预判操作结果以加速探索过程，并将认知负荷转移至触觉交互。我们提出了为自适应空间触觉屏幕阅读器创建触觉覆盖层的设计准则，并探讨了其在探索性数据分析和日常应用导航场景之外的普适性。