指導教授：李明穗臺灣大學：資訊工程學研究所匡載君Kuang, Chai-ChunChai-ChunKuang2014-11-262018-07-052014-11-262018-07-052014http://ntur.lib.ntu.edu.tw//handle/246246/261469如果要將文件或書本數位化，我們通常會因為方便以及可以快速取得選擇使用數位相機而非掃描機。但是用相機拍照得到的影像會有很多問題，像是反光 (specular reflection)、不均勻的照明所形成的亮暗不均 (non-uniform illumination)、透視投影或是文件本身的彎曲所造成的扭曲 (perspective and geometric distortions)。為了解決這些問題，過去幾十年提出了很多的方法。不過這些方法都只能一次解決其中的一個或兩個問題。 本篇論文提出了一個較完整的系統可以一次解決上面所提到的三個問題。其基於在同一個角度拍攝閃光與非閃光影像。利用閃光與非閃光影像組合成反光消除的影像。接著再使用影像增強 (image enhancement) 的方法去除不均勻照明所形成的亮暗不均。最後再利用邊界內差 (boundary interpolation) 的方法矯正透視投影和文件彎曲所造成的扭曲。 實驗結果顯示本論文的方法可以在不使用特殊硬體設備以及沒有使用者輸入的情況下，將影像矯正成沒有反光、沒有亮暗不均也沒有透視投影或文件彎曲所造成的扭曲。Digitizing documents or books by digital cameras are preferred instead of flatbed scanners due to convenience and fast response. However, camera-captured document images have many problems, such as specular reflection, non-uniform illumination, and perspective and geometric distortions. In order to solve these defects, many methods have been proposed in the last decades. Nevertheless, they can only overcome one or two of the drawbacks mentioned above each time. This thesis proposes an integrated system to deal with the three problems based on flash and no-flash image pairs taken at the same angle. Flash and no-flash image pairs are used to compose specular reflection removal images. And then an image enhancement method is applied to remove non-uniform illumination. Finally, boundary interpolation provides an effective solution to perspective and geometric distortions. The experimental results show that our system can restore the frontal-flat views of the documents and remove specular reflection and non-uniform illumination without any specific hardwares or user inputs.口試委員會審定書 ........................... # 誌謝 ........................... i 中文摘要 ........................... ii ABSTRACT ........................... iii CONTENTS ........................... iv LIST OF FIGURES ........................... vi LIST OF TABLES ........................... viii Chapter 1 Introduction ........................... 1 1.1 Introduction ........................... 1 1.2 Thesis Organization ........................... 2 Chapter 2 Related Work ........................... 3 2.1 Specular Reflection Removal ........................... 3 2.2 Non-uniform Illumination Removal ........................... 4 2.3 Perspective and Geometric Correction ........................... 8 Chapter 3 Background ........................... 11 3.1 Mean-value Cloning ........................... 11 3.1.1 Mean-value Coordinates ........................... 11 3.1.2 Mean-value Seamless Cloning ........................... 12 3.2 Image Enhancement ........................... 13 3.2.1 Enhancement of V Component Image ........................... 13 3.2.2 Enhancement of S Component Image ........................... 15 3.3 Bilinear Coons Patch ........................... 15 Chapter 4 Proposed Method ........................... 17 4.1 System Overview ........................... 18 4.2 Registration ........................... 19 4.3 Specularity Removal ........................... 20 4.3.1 Specularity Detection of Flash and No-flash Images ........................... 21 4.3.2 Shadow Detection of No-flash Images ........................... 28 4.3.3 Final Cloning Mask Acquirement and Specularity Removal ........................... 29 4.3.4 Experimental Results of Specularity Removal ........................... 29 4.4 Image Enhancement ........................... 31 4.5 Perspective and Geometric Correction ........................... 33 4.5.1 Boundary Extraction ........................... 34 4.5.2 Aspect Ratio Estimation ........................... 36 4.5.3 Boundary Interpolation ........................... 36 4.5.4 Experimental Results of Perspective and Geometric Correction ........................... 37 Chapter 5 Experimental Results ........................... 38 5.1 Resultant Images ........................... 38 5.2 Comparison ........................... 44 Chapter 6 Conclusion and Future Work ........................... 46 6.1 Conclusion ........................... 46 6.2 Discussion and Future Work ........................... 46 REFERENCE ........................... 483159389 bytesapplication/pdf論文公開時間：2019/07/29論文使用權限：同意有償授權(權利金給回饋學校)文件影像處理閃光與非閃光影像反光消除不均勻照明消除透視投影和文件彎曲矯正thesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/261469/1/ntu-103-R01922061-1.pdf