Light emitting diodes (LED) are becoming the dominant lighting elements due to their efficiency. Optical camera communications (OCC), the branch of visible light communications (VLC) that uses video cameras as receivers, is a suitable candidate in facilitating the development of new communication solutions for the broader public because video cameras are available on almost any smartphone nowadays. Unfortunately, most OCC systems that have been proposed until now require either expensive and specialized high-frame-rate cameras as receivers, which are unavailable on smartphones, or they rely on the rolling shutter effect, being sensitive to camera movement and pointing direction, they produce light flicker when low-frame-rate cameras are used, or they must discern between more than two light intensity values, affecting the robustness of the decoding process. This paper presents in detail the design of an OCC system that overcomes these limitations, being designed for receivers capturing 120 frames per second and being easily adaptable for any other frame rate. The system does not rely on the rolling shutter effect, thus making it insensitive to camera movement during frame acquisition and less demanding about camera resolution. It can work with reflected light, requiring neither a direct line of sight to the light source nor high resolution image sensors. The proposed communication is invariant to the moment when the transmitter and the receiver are started as the communication is self-synchronized, without any other exchange of information between the transmitter and the receiver, without producing light flicker, and requires only two levels of brightness to be detected (light on and light off). The proposed system overcomes the challenge of not producing light flicker even when it is adapted to work with very low-frame-rate receivers. This paper presents the statistical analysis of the communication performance and discusses its implementation in an indoor localization system.

中文翻译：

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针对低帧率接收器优化的稳健 OCC 系统

发光二极管 (LED) 因其效率而成为主要的照明元件。光学摄像机通信 (OCC) 是可见光通信 (VLC) 的一个分支，它使用摄像机作为接收器，是促进为广大公众开发新通信解决方案的合适人选，因为如今几乎所有智能手机都可以使用摄像机。不幸的是，迄今为止提出的大多数 OCC 系统要么需要昂贵且专用的高帧率相机作为接收器，而这在智能手机上是不可用的，要么它们依赖于滚动快门效应，对相机移动和指向方向敏感，它们使用低帧率相机时会产生光闪烁，或者它们必须区分两个以上的光强度值，影响解码过程的鲁棒性。本文详细介绍了克服这些限制的 OCC 系统的设计，该系统设计用于每秒捕获 120 帧的接收器，并且可以轻松适应任何其他帧速率。该系统不依赖卷帘快门效果，因此在帧采集过程中对相机移动不敏感，对相机分辨率的要求较低。它可以使用反射光，既不需要直接看到光源，也不需要高分辨率图像传感器。所提出的通信对于发射器和接收器开始的时刻是不变的，因为通信是自同步的，发射器和接收器之间没有任何其他信息交换，不会产生光闪烁，并且只需要检测两个级别的亮度（开灯和关灯）。所提出的系统克服了不产生光闪烁的挑战，即使它适用于非常低帧速率的接收器。本文介绍了通信性能的统计分析，并讨论了其在室内定位系统中的实现。