本論文運用影像處理方法來降低背景光線及散射效應對水下雷射測距系統性能之影響，同時利用田口品質方法提高水下雷射測距的重現性。在影像處理法方面，本論文運用影像最小平方近似、亮度調整、對比調整、以及影像三原色處理來降低背景光線對測距品質的影響，同時利用亮度重心法來提昇雷射光點座標的量測精度，此外，本論文也探討測距系統加掛濾鏡對測距品質的影響。為了以最少的實驗次數找出影像處理方法的參數特性及最佳參數水準組合，同時考量水中濁度與環境照度對測距品質的影響，本論文利用實驗設計程序來規劃相關實驗，將各種影像處理法的控制因子和雜訊因子配置於直交表上，並依據直交表的因子水準配置擷取後續分析所需之測距影像，
接著利用田口品質方法進行實驗訊雜比的計算與變異分析，找出各演算處理法的最佳因子水準組合，然後由實驗的結果探討各影像處理法提昇測距品質的成效，最後進行實驗驗證，以確定各影像處理法都能使測距系統在不同濁度照度條件下，達到最佳的量測品質。此外，本論文也探討影像處理法降低散射效應的可行性，並進一步分析此方法對於降低雷射散射影像的條件限制。由實驗的結果可知，測距系統加掛濾鏡可以很有效地提高測距品質。而本論文提出之影像最小平方近似處理方法對測距品質的提昇則優於使用外掛濾鏡以及其他的影像處理方法，且經濾鏡濾波後的影像，還可經最小平方近似處理再進一步提昇測距品質。此外，當散射亮點的面積小於雷射光點且其分佈較稀疏時，使用最小平方近似處理也能有效降低散射效應。

This paper attempts to use image processing methods to reduce the influences of ambient
light and scattering effect on the performance of an underwater range finder. The Taguchi method, as well, is employed to increase the repeatability of underwater range finding. In this study, the image processing methods of the least-squares approximation, brightness and contrast adjustment, and primary color processing are presented. The illumination center is also used to estimate the position of the laser spot in the image. In addition, a bandpass optical filter at the receiving end is used to investigate the effects of filters on the quality of range finding. To verify the effectiveness of the proposed image processing methods, a series of DOE process runs are carried out to study effects of the design parameters on quality of range finding. For each image processing method, its corresponding control factors and levels are assigned to an inner orthogonal array. To make the proposed image processing methods robust against noises, both environmental illumination and turbidity are forced into the experiments by utilizing an outer orthogonal array. Images for processing are then captured under different noise conditions in accordance with the allocation of the outer noise array. And, according to the layout of the inner array, the S/N ratio of each treatment combination is calculated. After that, the optimum combination of control factors is predicted through the analysis of variance. Then, the confirmation experiments are carried out to verify that the combination of control factors at the perceived best levels is valid. Based on the results of experiments and analyses, it is found that the least-squares approximation is better than other proposed image processing methods for increasing the quality of range finding. Moreover, the effect
of increasing quality of range finding by using the least-squares approximation is superior to that of using a bandpass optical filter. Even though a range finding system has incorporated a bandpass optical filter for filtering out unwanted noises, the quality of range finding can still be increased distinctly while the algorithm of the least-squares approximation is employed. As well, the least-squares approximation is feasible to reduce the scattering effects in the laser images if the size of the sparse backscattering light spot is smaller than that of the target light spot.

目錄………………………………………………………………… i
第一章 緒論……………………………………………………… 1
1.1 研究背景…………………………………………………… 1
1.2 文獻回顧…………………………………………………… 2
1.3 研究目的…………………………………………………… 4
1.4 論文架構…………………………………………………… 5
第二章 研究方法………………………………………………… 6
2.1 影像最小平方近似處理法………………………………… 6
2.1.1 影像處理流程……………………………………… 6
2.1.2 影像處理演算法…………………………………… 7
2.2 影像三原色法……………………………………………… 11
2.3 濾鏡濾波法………………………………………………… 14
2.4 雷射光點位置演算法……………………………………… 15
2.5 影像亮度與對比…………………………………………… 17
第三章 實驗設計與規劃………………………………………… 21
3.1 實驗設備…………………………………………………… 22
3.2 品質特性…………………………………………………… 26
3.3 實驗因子選擇……………………………………………… 27
3.3.1 控制因子…………………………………………… 27
3.3.2 雜訊因子…………………………………………… 28
3.4 直交表選擇與影像擷取…………………………………… 32
3.5 散射影像…………………………………………………… 37
第四章 實驗結果………………………………………………… 39
4.1 影像最小平方近似處理 ………………………………… 39
4.1.1 原始影像…………………………………………… 40
4.1.2 濾鏡濾波影像……………………………………… 42
4.2 影像最小平方近似處理與亮度對比調整………………… 44
4.2.1 原始影像…………………………………………… 44
4.2.2 濾鏡濾波影像……………………………………… 45
4.3 三原色處理………………………………………………… 47
4.3.1 原始影像…………………………………………… 49
4.3.2 濾鏡濾波影像……………………………………… 50
4.4 結論………………………………………………………… 54
第五章 驗證實驗………………………………………………… 56
5.1 最小平方近似處理………………………………………… 56
5.1.1 原始影像…………………………………………… 56
5.1.2 濾鏡濾波影像……………………………................... 59
5.2 最小平方近似處理與亮度對比調整……………………… 61
5.2.1 原始影像…………………………………………… 61
5.2.2 濾鏡濾波影像……………………………………… 62
5.3 三原色處理………………………………………………… 63
5.3.1 原始影像…………………………………………… 63
5.3.2 濾鏡濾波影像……………………………………… 65
5.4 散射光濾除效果之可行性分析…………………………… 67
第六章 討論與結論……………………………………………… 70
附錄A 田口方法………………………………………………… 81
A.1 品質特性………………………………………………… 81
A.2 直交表…………………………………………………… 83
A.3 實驗設計程序(DOE process）…………………………… 87

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