Khan Tareq H, Wahid Khan A
Department of Electrical and Computer Engineering, University of Saskatchewan, Saskatoon, SK S7N5A9, Canada.
Sensors (Basel). 2014 Nov 4;14(11):20779-99. doi: 10.3390/s141120779.
In this paper, a new low complexity and lossless image compression system for capsule endoscopy (CE) is presented. The compressor consists of a low-cost YEF color space converter and variable-length predictive with a combination of Golomb-Rice and unary encoding. All these components have been heavily optimized for low-power and low-cost and lossless in nature. As a result, the entire compression system does not incur any loss of image information. Unlike transform based algorithms, the compressor can be interfaced with commercial image sensors which send pixel data in raster-scan fashion that eliminates the need of having large buffer memory. The compression algorithm is capable to work with white light imaging (WLI) and narrow band imaging (NBI) with average compression ratio of 78% and 84% respectively. Finally, a complete capsule endoscopy system is developed on a single, low-power, 65-nm field programmable gate arrays (FPGA) chip. The prototype is developed using circular PCBs having a diameter of 16 mm. Several in-vivo and ex-vivo trials using pig's intestine have been conducted using the prototype to validate the performance of the proposed lossless compression algorithm. The results show that, compared with all other existing works, the proposed algorithm offers a solution to wireless capsule endoscopy with lossless and yet acceptable level of compression.
本文提出了一种用于胶囊内镜（CE）的新型低复杂度无损图像压缩系统。该压缩器由一个低成本的YEF颜色空间转换器和结合了哥伦布-莱斯编码与一元编码的可变长度预测器组成。所有这些组件都针对低功耗、低成本且本质无损进行了大量优化。因此，整个压缩系统不会导致任何图像信息丢失。与基于变换的算法不同，该压缩器可以与以光栅扫描方式发送像素数据的商用图像传感器接口，从而无需大容量缓冲存储器。该压缩算法能够分别以78%和84%的平均压缩率处理白光成像（WLI）和窄带成像（NBI）。最后，在单个低功耗65纳米现场可编程门阵列（FPGA）芯片上开发了一个完整的胶囊内镜系统。该原型是使用直径为16毫米的圆形印刷电路板开发的。使用该原型对猪肠道进行了多次体内和体外试验，以验证所提出的无损压缩算法的性能。结果表明，与所有其他现有工作相比，所提出的算法为无线胶囊内镜提供了一种无损且压缩水平可接受的解决方案。
