A new concept of assistive virtual keyboards based on a systematic review of text entry optimization techniques

Abstract Introduction: Due to the increasing popularization of computers and the internet expansion, Alternative and Augmentative Communication technologies have been employed to restore the ability to communicate of people with aphasia and tetraplegia. Virtual keyboards are one of the most primitive mechanisms for alternatively entering text and play a very important role in accomplishing this task. However, the text entry for this kind of keyboard is much slower than entering information through their physical counterparts. Many techniques and layouts have been proposed to improve the typing performance of virtual keyboards, each one concerning a different issue or solving a specific problem. However, not all of them are suitable to assist seriously people with motor impairment. Methods: In order to develop an assistive virtual keyboard with improved typing performance, we performed a systematic review on scientific databases. Results: We found 250 related papers and 52 of them were selected to compose. After that, we identified eight essentials virtual keyboard features, five methods to optimize data entry performance and five metrics to assess typing performance. Conclusion: Based on this review, we introduce a concept of an assistive, optimized, compact and adaptive virtual keyboard that gathers a set of suitable techniques such as: a new ambiguous keyboard layout, disambiguation algorithms, dynamic scan techniques, static text prediction of letters and words and, finally, the use of phonetic and similarity algorithms to reduce the user's typing error rate.

摘要与引言：随着计算机的日益普及与互联网的持续扩张，辅助与替代沟通（Alternative and Augmentative Communication, AAC）技术已被用于恢复失语症与四肢瘫痪患者的沟通能力。虚拟键盘（Virtual Keyboard）是最为基础的替代文本输入机制之一，在辅助此类患者完成沟通任务中发挥着至关重要的作用。然而，此类虚拟键盘的文本输入速度远低于实体物理键盘。学界已提出诸多技术与布局方案以提升虚拟键盘的打字性能，各方案均针对不同的应用场景或解决特定的技术痛点，但并非所有方案都适用于辅助存在严重运动功能障碍的用户。
方法：为开发一款打字性能更优的辅助虚拟键盘，我们针对学术数据库开展了系统性综述研究。
结果：我们共检索到250篇相关文献，最终选取其中52篇纳入本综述。此后，我们梳理出8项核心虚拟键盘特性、5种优化文本输入性能的方法，以及5项用于评估打字性能的指标。
结论：基于本次综述，我们提出一款辅助型、优化型、紧凑型且自适应的虚拟键盘概念，该键盘集成了一系列适配的技术手段，包括：新型歧义化键盘布局、歧义消解算法、动态扫描技术、字母与单词静态文本预测，以及采用语音与相似度算法以降低用户的打字错误率。