Visual codes, such as QR codes, are widely used in several applications for conveying information to users. However, user interactions based on spatial codes (e.g., displaying codes on phone screens for exchanging contact information) are often tedious, time consuming, and prone to errors due to image corruptions such as noise, blur, saturation, and perspective distortions. We propose Light Codes (LICO), a novel method for fast and fluid exchange of information among users. Light codes are based on transmitting and receiving temporal codes (instead of spatial) using compact and low-cost transceiver devices. The resulting approach enables seamless and near instantaneous exchange of short messages among users with minimal physical and cognitive effort. We design novel coding techniques, hardware prototypes, and applications that are optimized for human-centric communication, and facilitate fast and fluid user-to-user interactions in various challenging conditions, including a range of distances, motion, and ambient illumination. We evaluate the performance of the proposed methods both via quantitative analysis and user study based comparisons with several existing approaches including display-camera links, Bluetooth, and near-field communication, which show strong preference toward Light Codes in various real-world application scenarios.

视觉代码（例如 QR 代码）广泛用于向用户传达信息的多种应用中。然而，基于空间代码的用户交互（例如，在电话屏幕上显示代码以交换联系信息）通常是乏味、耗时的，并且容易由于图像损坏（例如噪声、模糊、饱和度和透视扭曲）而出现错误。我们提出了轻码（LICO），这是一种在用户之间快速、流畅地交换信息的新颖方法。光代码基于使用紧凑且低成本的收发器设备发送和接收时间代码（而不是空间代码）。由此产生的方法能够以最少的体力和认知努力在用户之间无缝且近乎即时地交换短消息。我们设计新颖的编码技术、硬件原型、以及针对以人为中心的通信进行优化的应用程序，并在各种具有挑战性的条件下（包括一系列距离、运动和环境照明）促进快速、流畅的用户间交互。我们通过定量分析和基于用户研究的方法与几种现有方法（包括显示相机链接、蓝牙和近场通信）的比较来评估所提出方法的性能，这些方法在各种实际应用场景中表现出对光代码的强烈偏好。