Liu Gang, Yan Guozheng, Zhu Bingquan, Lu Li
Institute of Precise Engineering and Intelligent Microsystems, Shanghai Jiaotong University, Shanghai, 200240, People's Republic of China.
Med Biol Eng Comput. 2016 Nov;54(11):1779-1791. doi: 10.1007/s11517-016-1472-2. Epub 2016 Mar 25.
In recent years, wireless capsule endoscopy (WCE) has been a state-of-the-art tool to examine disorders of the human gastrointestinal tract painlessly. However, system miniaturization, enhancement of the image-data transfer rate and power consumption reduction for the capsule are still key challenges. In this paper, a video capsule endoscopy system with a low-power controlling and processing application-specific integrated circuit (ASIC) is designed and fabricated. In the design, these challenges are resolved by employing a microimage sensor, a novel radio frequency transmitter with an on-off keying modulation rate of 20 Mbps, and an ASIC structure that includes a clock management module, a power-efficient image compression module and a power management unit. An ASIC-based prototype capsule, which measures Φ11 mm × 25 mm, has been developed here. Test results show that the designed ASIC consumes much less power than most of the other WCE systems and that its total power consumption per frame is the least. The image compression module can realize high near-lossless compression rate (3.69) and high image quality (46.2 dB). The proposed system supports multi-spectral imaging, including white light imaging and autofluorescence imaging, at a maximum frame rate of 24 fps and with a resolution of 400 × 400. Tests and in vivo trials in pigs have proved the feasibility of the entire system, but further improvements in capsule control and compression performance inside the ASIC are needed in the future.
近年来，无线胶囊内镜（WCE）已成为一种用于无痛检查人体胃肠道疾病的先进工具。然而，系统小型化、提高图像数据传输速率以及降低胶囊的功耗仍然是关键挑战。本文设计并制造了一种具有低功耗控制和处理专用集成电路（ASIC）的视频胶囊内镜系统。在设计中，通过采用微图像传感器、一种开关键控调制速率为20 Mbps的新型射频发射器以及一种包含时钟管理模块、高效图像压缩模块和电源管理单元的ASIC结构来解决这些挑战。这里开发了一种基于ASIC的原型胶囊，其尺寸为Φ11 mm×25 mm。测试结果表明，所设计的ASIC比大多数其他WCE系统消耗的功率要少得多，并且其每帧的总功耗最低。图像压缩模块可以实现高近无损压缩率（3.69）和高图像质量（46.2 dB）。所提出的系统支持多光谱成像，包括白光成像和自发荧光成像，最大帧率为24 fps，分辨率为400×400。在猪身上进行的测试和体内试验证明了整个系统的可行性，但未来需要对ASIC内部的胶囊控制和压缩性能进行进一步改进。
