标题: | 环场扫描式胶囊内视镜之设计与验证 Implementation and verification of radial imaging capsule endoscope (RICE) |
作者: | 郑伟德 Jeng, Wei-De 欧阳盟 Mang, Ou-Yang 电控工程研究所 |
关键字: | 环场扫描式胶囊内视镜;锥状镜;环场扫描;小肠出血;Radial imaging capsule endoscope;Cone mirror;Radial imaging;Small bowel bleeding |
公开日期: | 2015 |
摘要: | 本研究提出新一代胶囊内视镜‘环场扫描式胶囊内视镜’,利用环场扫描之特色来改善传统前看式胶囊内视镜之缺点。环场扫描式胶囊内视镜透过利用一个锥状镜、环形透明观景窗以及光学聚焦系统来实现环场扫描之特色。透过光学软体模拟,有效改善弧史(Sagittal)以及子午(Tangential)平面之像差。最终完成之设计达到焦数为4.2,视角为65.08度,以及第四到第六视场之光点大小均小于17 um,与传统前看式比起来光点大小改善达50 %,并且弧史平面之第五视场其MTF在空间频率为100 lp/mm时,从原本7 %提升到 36 %。另外在照明系统之设计部分,由于环场扫描式胶囊内视镜会受到杂散光影响降低照明均匀度。但透过本研究之优化设计后,例如改变LED之位置,切掉部分锥状镜之锥尖部分,甚至透过多层镀膜,照明均匀度从原本12 %提升到69 %。在影像处理方面,本研究提出三个方法,意即平均绝对误差、均方误差、以及皮尔森相关系数法来进行影像相似度之比对,以进行影像之缝合。缝合结果可以发现皮尔森相关系数法之演算法最为强健,不会受到影像某部分之亮度有剧烈变化而受到影响。并且透过皮尔森相关系数法,其缝合之结果之原本影像之讯杂比高达80.69 dB。本研究甚至透过临床活体实验进行验证,将所拍摄之小猪肠道内影像进行缝合,发现此演算法可运用于复杂之肠道环境。最后,针对环场扫描式胶囊内视镜之色差部分,提出色彩校正之演算法,避免因为色差造成误诊。由于环场扫描式胶囊内视镜之光学系统会造成色差,为了解决此问题本研究提出系数法与复数多项式映射法来将失真之色彩点映射到正确之色彩点。透过系数法与复数多项式映射法将原本高达21.45之色差(CIE DE2000)改善到1.53,透过复数多项式映射法可改善至1.32,此色差值已经低于人眼可辨识之色差1.5。 本研究提出环场扫描式胶囊内视镜,透过全景拍摄之设计,可以轻易地撷取更多小肠内部影像资讯,避免传统前看式胶囊内视镜容易因视角有限造成死角问题。此设计对于小肠出血诊断非常重要,对于诊断率之提高有一定之帮助。 In this study, the radial imaging capsule endoscope (RICE) system was proposed. It differs from the conventional front imaging capsule endoscope (FICE) system. RICE uses a cone mirror, a radial window shell and a focus optical module to implement a radial imaging system. In minimizing the sagittal and tangential aberrations, the optical module of the RICE achieved an F-Number of 4.2, a viewing angle of 65.08°, and the spot sizes from 4th to 6th fields are less than 17 um. For the illumination system, this study proposed an optimal design to improve the uniformity of the illumination. The illumination uniformity in the RICE was increased from its original value of 0.128 up to 0.69. For the image processing, three algorithms, mean absolute error (MAE), mean square error (MSE), Pearson correlation coefficient, were used to stitch the images together. The Pearson correlation coefficient method was the most effective algorithm because it yields the highest peak signal to noise ratio (PSNR) of higher than 80.69 dB compare to original image. Furthermore, this algorism was verified by a clinical animal experiment. Finally, color calibration was carried out. Before color calibration, the color difference in RICE was 21.45 (CIE DE2000). Through the proposed conformal mapping, the color difference was substantially reduced to 1.32, and the color difference is imperceptible for human eye because it is lower than 1.5. In summary, this study developed a prototype of RICE, which yielded panoramic view, largely increases the capability to access the small bowel without losing any information. This is very important for diagnosis of obscure small bowel bleeding, hence, improve the diagnostic yield. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT079912812 http://hdl.handle.net/11536/126565 |
显示于类别: | Thesis |