[1] [1] Nakamura J. Image Sensors and Signal Processing for Digital Still Cameras［M］. Xu J T, Gao J, Nie H M, trans. Beijing: Tsinghua University Press, 2015.

[3] [3] Chen Y. Study of CMOS vertical integrated pixel and image sensor［D］. Hangzhou: Zhejiang University, 2009.

[4] [4] Jia X H, Zhang Q Y, Duan X D, et al. Medical endoscopes—Capsule endoscopes: YY 1298–2016［S］. Beijing: China Standard Press, 2018.

[5] [5] Jia X H, He T, Yan Q L, et al. Medical endoscopes—rigid endoscope—Part 1: optical properties and test methods: YY 0068.1–2008［S］. Beijing: China Standard Press, 2009.

[6] [6] Jia X H, Yan Q L, Wen Y. Evaluation base and method of medical rigid endoscope distortion［J］. Acta Optica Sinica, 2006, 26(8): 1226–1230.

[7] [7] Liu M C, Zhang L, Liu P P, et al. Design of lens for 3 mega-pixel mobile phone camera［J］. Journal of Applied Optics, 2008, 29(6): 944–948.

[8] [8] Gu J D, Xiang Y. Optical system design of electronic endoscope［J］. Journal of Changchun University of Science and Technology (Natural Science Edition), 2015, 38(2): 18–20, 24.

[9] [9] Wang J H, Lu J H, Xu M. Optical design of the single-chip capsule endoscopt with harmonic diffraction surface［J］. Laser & Optoelectronics Progress, 2012, 49(12): 122203.

[10] [10] Zhu J W, Ding G L. Design of an ultra-small wide-angle medical endoscope lens［J］. Laser & Optoelectronics Progress, 2014, 51(9): 181–186.

[11] [11] Zhang Y H, Huang Z H. The progress of capsule endoscope technology［J］. Modern Instruments, 2006, 12(4): 4–7.

[13] [13] Guo X, Zhang W, Su J H, et al. Design of a focus-tunable capsule endoscope system［J］. Acta Photonica Sinica, 2015, 44(5): 0522004.

[14] [14] Ye B, Wang L Q, Shi Y, et al. High resolution miniaturized CMOS camera module for medical electronic endoscope［J］. Acta Photonica Sinica, 2010, 39(11): 1951–1955.

[15] [15] Ding Q, Wang H N. An imaging technique of microcapsule endoscope using a GRIN lens［J］. Acta Photonica Sinica, 2004, 33(7): 889–892.

[16] [16] Tseng Y C, Han P, Hsu H C, et al. A flexible FOV capsule endoscope design based on compound lens［J］. Journal of Display Technology, 2016, 12(12): 1–7.

[17] [17] Ouyang M, Jeng W D. Design and analysis of radial imaging capsule endoscope (RICE) system［J］. Optics Express, 2011, 19(5): 4369–4383.