本論文透過水下光傳遞之能量衰減分析，討論雷射光傳遞的能量衰減數據並建構符合水下雷射光能量與距離的關係曲線，推算雷射光源與目標物間的距離。其中，雷射光源相較其他光源能夠提供較高的能量外，具有極小的光束角度，可以降低散射效應影響光能量傳遞之衰減，於光能量分析上擁有極大的優勢。本論文提出兩種相異的測距模型建構方法：(1)光衰理論法，使用光衰理論推算光傳遞時能量損失的情況，討論影響傳遞之吸收係數、初始光能量及濁度和散射係數間的關係，獲取理論相關參數建構水下測距模型。(2)實驗擬合法，透過實際於水量測的光能量數據，直接進行模型之擬合，並討論擬合函數的距離預測性。實際水下測距，在較低濁度之1.12-1.18NTU時，光衰理論法之藍光雷射整體測距誤差為0.4129m，紅光雷射整體測距誤差為0.3184m；實驗擬合法最佳模型之藍光雷射整體測距誤差為0.0493m，紅光雷射的整體測距誤差為0.071m。在較高濁度之2.38-2.41NTU時，光衰理論法之藍光雷射整體測距誤差為0.8831m，紅光雷射整體測距誤差為0.1994m；實驗擬合法最佳模型之藍光雷射整體測距誤差為0.1454m，紅光雷射的整體測距誤差為0.1299m。最後，本論文提出之實驗擬合法的模型能有效降低水下測距的整體誤，並優於光衰理論法，整體測距誤差皆小於0.15m。若於較乾淨之水質濁度，其測距誤差可再降低至小於0.08m，印證本論文提出運用水下光能量衰減模型之測距系統的可行性，為水下測距領域提供新型態的被動測距方式。

In this thesis, an underwater laser ranging system is constructed through the energy attenuation analysis of underwater light transmission. Compared with other light sources, the laser light source can provide higher energy, and has a very small beam angle. We propose two different methods for constructing ranging models: (1) the optical attenuation method, which uses theories to calculate the energy loss during light transmission, and obtains theoretical parameters to construct an underwater ranging model. (2) the experimental fitting method, which directly fits the model through the light energy data measured in the water. In the underwater ranging experiment, when the turbidity is 1.12-1.18NTU, the overall ranging error of the blue laser by the optical attenuation method is 0.4129m, and the red laser is 0.3184m. The overall ranging error of blue laser by the experimental fitting method is 0.0493m, and the red laser is 0.071m. When the higher turbidity is 2.38-2.41NTU, the overall ranging error of the blue laser by the optical attenuation method is 0.8831m, and the red laser is 0.1994m. The overall ranging error of blue laser by the experimental fitting method is 0.1454m, and the red laser is 0.1299m. Finally, the model of the experimental fitting method proposed can effectively reduce the overall error of underwater ranging, and is better than the optical attenuation method, and the overall ranging error is less than 0.15m. If the turbidity of the water, the ranging error can be further reduced to less than 0.08m. We confirmed the feasibility of the ranging system using the underwater light energy attenuation model, and provides a new type of passive ranging method for the underwater ranging field.

[1] C. Li, C. Guo, W. Ren, R. Cong, J. Hou, S. Kwong and D. Tao, “An Underwater Image Enhancement Benchmark Dataset and Beyond”, IEEE Transactions on Image Processing, Vol. 29, pp.4376-4389, 2019.
[2] G. Schirripa Spagnolo, L. Cozzella and F. Leccese, “Underwater Optical Wireless Communications: Overview”, Sensors, Vol. 20, no. 8, pp.2261, 2020.
[3] F. A. Furfari, “A different kind of chemistry: a history of tungsten halogen lamps”, IEEE Industry Applications Magazine, Vol. 7, no. 6, pp.10-17, 2001.
[4] J. F. Waymouth, “Metal halide lamps”, Proceedings of the IEEE, Vol. 59, no. 4, pp.629-633, 1971.
[5] 堅玉，「國內金鹵燈生產設備的現狀與發展」，照明工程學報，Vol. 14，no. 1，pp.27-29、50，2003。
[6] G. Held, “Introduction to light emitting diode technology and applications”, CRC press, pp.5,18-20, 2016.
[7] J. R. Curran, “A strategy for the use of light emitting diodes by autonomous underwater vehicles“, Massachusetts Institute of Technology, Department of Ocean Engineering, Doctoral dissertation, 2004.
[8] I. Vasilescu, C. Detweiler and D. Rus, “Color-accurate underwater imaging using perceptual adaptive illumination”, Autonomous Robots, Vol. 31, no. 2, pp.285, 2011.
[9] 陳志宇，「水下LED色彩補償照明模組之設計與評估」，國立成功大學，系統及船舶機電工程學系，碩士論文，2019。
[10] 蔡旻靜，「多光色LED照明系統於水下物體色彩還原之設計與實現」，國立成功大學，系統及船舶機電工程學系，碩士論文，2020。
[11] S. Jiang and S. Georgakopoulos, “Electromagnetic Wave Propagation into Fresh Water”, Journal of Electromagnetic Analysis and Applications, Vol. 3, no. 7, pp.6, 2011.
[12] J. M. Rüeger, “Electronic distance measurement: An introduction”, Springer Science & Business Media, pp.1-47, 2012.
[13] L. Mullen, V. M. Contarino, A. Laux, B. Concannon, J. Davis, M. Strand and B. Coles, “Modulated laser line scanner for enhanced underwater imaging”, SPIE's International Symposium on Optical Science, Engineering, and Instrumentation, Vol. 3761, 1999.
[14] A. Laux, L. Mullen, P. Perez and E. Zege, “Underwater laser range finder”, SPIE Defense, Security, and Sensing, Vol. 8372, 2012.
[15] B. Peng, D. Jin, C. Ji, C. Pei and L. Sun, “An underwater laser three-dimensional imaging system”, SPIE-Sixth Symposium on Novel Photoelectronic Detection Technology and Application, Vol. 11455, 2020.
[16] S. Shatara and X. Tan, “An Efficient, Time-of-Flight-Based Underwater Acoustic Ranging System for Small Robotic Fish”, IEEE Journal of Oceanic Engineering, Vol. 35, no. 4, pp.837-846, 2010.
[17] 祝琨、楊唐文、阮秋琦、王紅波和韓建達，「基於雙目視覺的運動物體實時跟踪與測距」，機器人，Vol. 31，no. 4，pp.327-334，2009。
[18] X. Sun, Y. Jiang, Y. Ji, W. Fu, S. Yan, Q. Chen, B. Yu and X. Gan, “Distance Measurement System Based on Binocular Stereo Vision”, IOP Conference Series: Earth and Environmental Science, Vol. 252, no. 5, pp.052051, 2019.
[19] C. Lin, L. Xu and Z. Liu, “Digitization of Free-Swimming Fish Based on Binocular Stereo Vision”, Vol. 2, pp.363-368, 2015.
[20] 陳沖，「水的光學特性及其對水下成像的影響分析」，應用光學，Vol. 21，no. 4，pp.39-46，2000。
[21] J. E. Tyler, “Ocean analysis by means of Beer’s law”, Applied Optics, Vol. 15, no. 10, pp.2565-2567, 1976.
[22] L. Yan and Y. Lu, “Construction and Analysis of Light Energy Transfer Model Based on Underwater Environment”, Atlantis Press, pp.1239-1245, 2017.
[23] S. Q. Duntley, “Light in the Sea*”, Journal of the Optical Society of America, Vol. 53, no. 2, pp.214-233, 1963.
[24] J. D. Ingle Jr and S. R. Crouch, “Spectrochemical analysis”, Old Tappan, NJ (US); Prentice Hall College Book Division, United States, 1988.
[25] Y. Peng and P. C. Cosman, “Underwater Image Restoration Based on Image Blurriness and Light Absorption”, IEEE Transactions on Image Processing, Vol. 26, no. 4, pp.1579-1594, 2017.
[26] A. Yamashita, M. Fujii and T. Kaneko, “Color Registration of Underwater Images for Underwater Sensing with Consideration of Light Attenuation”, Proceedings 2007 IEEE International Conference on Robotics and Automation, pp.4570-4575, 2007.
[27] C. Liu and W. Meng, “Removal of water scattering”, 2010 2nd International Conference on Computer Engineering and Technology, Vol. 2, pp.V2-35-V32-39, 2010.
[28] J. Metz, “The geometry of Snell's law”, The Physics Teacher, Vol. 52, no. 3, pp.177-177, 2014.
[29] D. Drosdoff and A. Widom, “Snell’s law from an elementary particle viewpoint”, American Journal of Physics, Vol. 73, no. 10, pp.973-975, 2005.
[30] F. Bryant, “Snell's Law of Refraction”, Physics Bulletin, Vol. 9, no. 12, pp.317-317, 1958.
[31] W. Benenson, J. Harris, H. Stoecker and H. Lutz, “Handbook of Physics”, Springer Verlag, America, pp.335-408, 2002.
[32] P. D. T. Huibers, “Models for the wavelength dependence of the index of refraction ofwater”, Applied Optics, Vol. 36, no. 16, pp.3785-3787, 1997.
[33] Y. Zhang, Y. Guo, H. Wei, L. Lou, H. Song, P. Yang and C. Liu, “Influence of water on underwater distance measurement by a laser range finder”, OCEANS 2017 – Aberdeen, pp.1-5, 2017.
[34] W. Gomaa, A. El-Sherif and Y. El-Sharkawy, “Underwater laser detection system”, SPIE, Vol. 9342, 2015.
[35] 蘇紅雨、楊華元、余浩然、余德萍、龔嵐和李波，「海水光譜吸收/散射係數測量儀的研製」，中國測試技術，Vol. 33，no. 6，pp.5-9，2007。
[36] 鄧孺孺、何穎清、秦雁、陳啟東和陳蕾，「分離懸浮質影響的光學波段(400-900 nm)水吸收係數測量」，遙感學報，Vol. 16，no. 1，pp.174-191，2012。