臺灣博碩士論文加值系統

現代無線通訊技術的蓬勃發展已經與我們生活息息相關，人們對無線通訊技術的需求與日俱增，無奈可用的無線電頻譜有限。近年來，可見光通訊（VLC）備受關注，許多文獻指出，由於多出來的的可見光頻譜，可見光通訊有成為未來5G無線通訊理想解決方案的潛力。
在本篇論文中，我們以LED作為訊號傳送端，並以手機的互補式金屬氧化物半導體(Complementary metal-oxide-semiconductor, CMOS)相機作為訊號接收端來模擬可見光通訊系統，我們會介紹CMOS感測器所具有的滾動式快門效應以及如何應用在可見光通訊，接著說明解調前的前置處理以及如何解調可以有效改善誤碼率(BER)。然後，我們將其作更貼近實際的應用，把LED換成燈箱廣告看板作為訊號傳送端，並對測試結果進行討論。最後是結論與未來展望。

The rapid development of modern wireless communication technologies allow people to connect to the Internet nearly anywhere and anytime. The bandwidth demand for wireless communication is growing rapidly. Unfortunately, there is limited available electromagnetic spectrum in the traditional radio-frequency (RF) communications. Visible light communication (VLC) has attracted much attention in recent years. Many literatures indicate that VLC could be a promising solution for the 5G and beyond mobile wireless communication due to the availability of extra electromagnetic spectra in the visible light region.
In this thesis, we use a light-emitting-diode (LED) as the transmitter and the mobile phone embedded complementary-metal-oxide-semiconductor (CMOS) camera as the signal receiver in the VLC system. We will introduce the rolling shutter effect of the CMOS sensor and how this effect can be applied to VLC. Then, we illustrate different demodulation schemes to improve the bit-error-rate (BER). Afterwards, we apply the proposed scheme to a practical application. We use the advertisement light box backlight LED as a transmitter, and discuss the experiment results when different advertisements are posted on it. Finally, conclusion and future works are presented.

摘要 I
ABSTRACT II
誌謝 III
表目錄 V
圖目錄 VII
第一章 緒論 1
1-1前言 1
1-2研究動機 1
1-3章節提要 3
第二章 可見光通訊以LED作為發射端CMOS感測器作為接收端 5
2-1 前言 5
2-1-1 LED 5
2-1-2 比較CCD與CMOS影像感測器 5
2-1-3 滾動式快門效應(Rolling shutter effect) 8
2-2 實驗架構與解調流程 11
2-2-1 實驗架構 11
2-2-2 同步 12
2-2-3 解調流程 13
2-3 二值化的前置處理 16
2-3-1 減緩高光溢出效應之處理方法(Blooming Mitigation Scheme) 16
2-3-2 線性內插法 18
2-3-3 改善消光比之影像處理(Sharpen by Smoothing) 19
第三章 解調NRZOOK與誤碼率 22
3-1 閥值(THRESHOLDING) 22
3-1-1 二次函數曲線閥值法 22
3-1-2 Bradley Adaptive Scheme 23
3-1-3 Quick Adaptive Scheme 24
3-1-4 改良後的Quick Adaptive Scheme (Modified Quick Adaptive Scheme) 25
3-1-5 極值平均法(Extreme Value Average Thresholding) 27
3-2 實驗結果與討論 29
3-2-1 封包內為96 bits的誤碼率 30
3-2-2 封包內為128 bits的誤碼率 34
第四章 有背景雜訊的NRZOOK之解調 41
4-1 實驗架構 42
4-2 解調流程 43
4-3 實驗變因 44
4-4 實驗結果與討論 47
第五章 結論與未來發展 62
5.1 結論 62
5.2 未來展望 62
參考文獻 63
著作列表 65

[1] C. W. Chow, et al, "Digital Signal Processing for Light Emitting Diode Based Visible Light Communication, " (Invited paper) IEEE Photon. Soc. Newslett., 26, 9-13 (2012).
[2] https://axiang.cc/archives/19318
[3] Haas Harald et al., "What is LiFi?", Journal of Lightwave Technology, vol. 34.6, pp. 1533-1544, 2016.
[4] https://en.wikipedia.org/wiki/Triple_play_(telecommunications)
[5] Roberts, Richard D. "Undersampled frequency shift ON-OFF keying (UFSOOK) for camera communications (CamCom)." Wireless and Optical Communication Conference (WOCC), 2013 22nd. IEEE, 2013.
[6] Soon, Tan Jin. "QR code." Synthesis Journal 2008 (2008): 59-78.
[7] Hao, Tian, Ruogu Zhou, and Guoliang Xing. "COBRA: color barcode streaming for smartphone systems." Proceedings of the 10th international conference on Mobile systems, applications, and services. ACM, 2012.
[8] Burchardt, Harald, et al. "VLC: Beyond point-to-point communication." IEEE Communications Magazine 52.7 (2014): 98-105.
[9] Danakis, Christos, et al. "Using a CMOS camera sensor for visible light communication." Globecom Workshops (GC Wkshps), 2012 IEEE.
[10] http://kcs.kcjh.ptc.edu.tw/~spt/computer/digital-image/CCD-CMOS.htm\
[11] http://blog.xuite.net/brian923/getter/
[12] http://www.masters.tw/18871/
[13] http://alan594.tian.yam.com/posts/23144912
[14] Liang, Chia-Kai, Li-Wen Chang, and Homer H. Chen. "Analysis and compensation of rolling shutter effect" Image Precessing, IEEE Transactions on 17.8 (2008): 1323-1330.
[15] Rajagopal, Niranjini, Patrick Lazik, and Anthony Rowe. "Visual light landmarks for mobile devices." Proceedings of the 13th international symposium on Information processing in sensor networks. IEEE Press, 2014
[16] Chow, Chi-Wai, Chung-Yen Chen, and Shih-Hao Chen. "Enhancement of signal performance in LED visible light communications using mobile phone camera." IEEE Photonics Journal 7.5 (2015): 1-7.
[17] Richard D. Roberts "Undersampled frequency shift ON-OFF keying (UFSOOK) for camera communications (CamCom)" Wireless and Optical Communication Conference (WOCC), 2013 22nd. IEEE 2013.
[18] Chia-Wei Chen, Chi-Wai Chow, Yang Liu, and Chien-Hung Yeh. "Efficient demodulation scheme for rolling-shutter-patterning of CMOS image sensor based visible light communications." Optics Express 25.20 (2017): 24362-24367.
[19] Yang Liu, Kevin Liang, Hung-Yu Chen, Liang-Yu Wei, Chin-Wei Hsu, Chi-Wai Chow, and Chien-Hung Yeh. "Light encryption scheme using light-emitting diode and camera image sensor, " IEEE Photonics Journal, 8.1(2016).
[20] Chi-Wai Chow, Chung-Yen Chen, and Shih-Hao Chen, “Visible light communication using mobile-phone camera with data rate higher than frame rate,” Opt. Express 23(20), 26080–26085 (2015).
[21] Bradley, Derek, and Gerhard Roth. "Adaptive thresholding using the integral image." Journal of graphics, gpu, and game tools 12.2 (2007): 13-21.
[22] Wellner, Pierre D. "Adaptive thresholding for the DigitalDesk." Xerox, EPC1993-110 (1993).