IEEE Rev Biomed Eng. 2017;10:2-11. doi: 10.1109/RBME.2017.2697950. Epub 2017 Apr 25.
One of the significant challenges in capsule endoscopy (CE) is to precisely determine the pathologies location. The localization process is primarily estimated using the received signal strength (RSS) from sensors in the capsule system through its movement in the gastrointestinal (GI) tract. Consequently, the wireless CE (WCE) system requires improvement to handle the lack of the capsule instantaneous localization information and to solve the relatively low transmission data rate challenges. Furthermore, the association among the capsule's transmitter position, capsule location, signal reduction, and the capsule direction should be assessed. These measurements deliver significant information for the instantaneous capsule localization systems based on time-of-arrival approach, phase difference of arrival, RSS, electromagnetic, direction of arrival (DOA), and video tracking approaches are developed to locate the WCE precisely. This review introduces the acquisition concept of the GI medical images using the endoscopy with a comprehensive description of the endoscopy system components. Capsule localization and tracking are considered to be the most important features of the WCE system, thus this paper emphasizes the most common localization systems generally, highlighting the DOA-based localization systems and discusses the required significant research challenges to be addressed.
胶囊内镜（CE）面临的一个重大挑战是精确定位病变位置。该定位过程主要通过胶囊系统中的传感器在胃肠道（GI）中的运动来估计接收信号强度（RSS）。因此，无线 CE（WCE）系统需要改进，以处理缺乏胶囊即时定位信息的问题，并解决相对较低的传输数据速率挑战。此外，应评估胶囊发射器位置、胶囊位置、信号衰减和胶囊方向之间的关联。这些测量结果为基于到达时间、到达相位差、RSS、电磁、到达方向 (DOA) 和视频跟踪方法的即时胶囊定位系统提供了重要信息，这些方法被开发用于精确定位 WCE。本综述介绍了使用内窥镜获取 GI 医学图像的采集概念，并全面描述了内窥镜系统组件。胶囊定位和跟踪被认为是 WCE 系统最重要的特征，因此本文强调了最常见的定位系统，重点介绍了基于 DOA 的定位系统，并讨论了需要解决的重要研究挑战。
