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標題: | 具平玻璃介面成像系統水下物像對應及物點定位品質分析 Analysis of Underwater Object-to-Image Correspondence and Object Point Positioning Quality by Using Flat-Refractive Imaging System |
作者: | 王俊凱 Chun-Kai Wang |
指導教授: | 趙鍵哲 Jen-Jer Jaw |
關鍵字: | 水下攝影測量,具平玻璃介面成像系統,多介質,定位誤差,交會幾何,多視角, Underwater photogrammetry,Flat-refractive imaging system,Multi-media,Positioning error,Intersection geometry,Multi-view, |
出版年 : | 2024 |
學位: | 碩士 |
摘要: | 水下攝影測量的拍攝方式可分為自空氣往水中拍攝、或逕於水中拍攝,本研究探討後者並將相機置於防水殼中作業,此成像系統稱之為具平玻璃介面成像系統,優勢為此成像系統於拍攝位置的選擇具有較高靈活度,並且具有平面玻璃介面,可承受較大水壓,有機會裝配較高規格之相機以獲取較深之水下環境影像。異於單介質環境,此系統之成像路徑涵蓋水、玻璃及空氣三種介質,在折射效應影響下,光線行經於多介質成像環境中會產生偏折,不僅需有完善之內外方位及畸變差參數資訊,還有玻璃介面相關參數,包括玻璃厚度、透視中心到玻璃介面的距離、玻璃傾角、介質折射係數及其誤差等因素必須加入物像對應關係中探討,才能獲致具平玻璃介面成像系統正確的光線路徑。
而良好之定位品質為攸關三維點雲模型精度的關鍵之一,又三維定位品質受前述各影響因子的誤差影響,此外,因拍攝之靈活度,使用者可設定符合需求之攝像幾何,因此本研究欲整合各因子的參數誤差並搭配不同交會幾何之配置,分析對於雙像前方交會定位品質之影響。本研究首先採模擬實驗進行分析,自行模擬物點及符合實務且中庸之相關配置,並引入各參數誤差,在單像分析階段以真值物點至具誤差之單條光線間的距離做為實際精度,以真值物點於具誤差之單條光線上的投影點透過誤差傳播計算理論精度;雙像分析則以廣義最小二乘平差進行共軛光線之交會解算,使用理論精度與實際精度作為定位成果進而驗證模式合理性。而後佐以實際實驗,初步驗證實務工作的可執行性與有效性。此外,於模擬實驗及實際實驗階段皆納入不同交會角度以及多視角之分析於物像對應探討中。 Flat-refractive imaging system, one of the camera geometry of underwater photogrammetry involves the multi-medium environment during the imaging. Accordingly, refraction effect plays an important role in the object-to-image correspondence of flat-refractive imaging system. In order to employ the appropriate specification of the camera system, and support a better implementation when carrying out underwater photogrammetry using flat-refractive imaging system, this study focuses on the positioning quality in object space caused by influential factors through the actual imaging path. Moreover, clarifying the sensitivity of parameters in the object-to-image correspondence, as well as exploring the flexibility of different intersection geometry and multi-view configurations, is also one of the research objectives. The parameters related to flat-refractive imaging system discussed in this research include glass thickness, glass distance, glass interface tilt, and refractive index of air, glass, and water. Analysis of single ray and two rays are used in the simulated experiments. For the quality assessment of single-ray analysis, the empirical accuracy which is calculated from the projection distance from the object point to the ray traced into the water resulting from erroneous parameters and theoretical precision which is calculated by error propagation are analyzed. As for the quality assessment of two-ray analysis, intersection computation of conjugate imaging rays with refraction correction based on generalized least-squares adjustment is conducted to support the quality assessment for both theoretical precision and empirical accuracy. Subsequently, actual experiments are carried out to validate the feasibility and effectiveness of the object-to-image correspondence, and ascertain the consistency of quality between actual experiments and simulated experiments. Additionally, the analyses involving different intersection angles and multi-view are incorporated in both simulated and actual experiments to highlight the flexible camera geometry of flat-refractive imaging system. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/92669 |
DOI: | 10.6342/NTU202400529 |
全文授權: | 同意授權(限校園內公開) |
顯示於系所單位: | 土木工程學系 |
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