Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/8755
標題: 全景投影機處理器
Panorama Multiple Projector Processor
作者: 莊元銘
Chuang, Yuan-Ming
關鍵字: Geometric Correction;幾何校正;Multi-Projector System;Hardware Implementation;Image Processing;多投影機系統;硬體實現;影像處理
出版社: 電機工程學系所
引用: [1]R. Raskar, J. V. Baar, P. Beardsley, T. Willwacher, S. Rao, and C. Forlines, “iLamps: Geometrically Aware and Self-Configuring Projectors”, ACM Transactions on Graphics, vol. 22, pp. 809-818, 2003. [2]M. Harville, B. Culbertson, I. Sobel, D. Gelb, A. Fitzhugh, D. Tanguay, “Practical Methods for Geometric and Photometric Correction of Tiled Projector Displays on Curved Surfaces”, Computer Vision and Pattern Recognition Workshop, pp. 5-5, 2006. [3]Wun-Yi Lee, “Low-Cost Smart Projector for Home Entertainment”, MCU-CCE Master''s Thesis, 2007. [4]Paul Bourke, “Edge blending using commodity projectors”, http://local.wasp.uwa.edu.au/~pbourke/texture_colour/edgeblend/, 2004. [5]R. Raskar, J. V. Baarm, J. X. Chai, “A Low-Cost Projector Mosaic with Fast Registration”, Proc. of Asian Conference on Computer Vision, 2002. [6]Heckbert, Paul S., “Fundmentals of Texture Mapping and Image Warping”, Technical Report Identifier: CSD-89-516, June 17, 1989. [7]R. Raskar, P. Beardsley, “A Self-Correcting Projector”, IEEE Computer Society Conference on Computer Vision and Pattern Recognition, vol. 2, pp. 504-508, December 2001 [8]R. Szeliski and H. Shum, “Creating Full view Panoramic Image Mosaics and Environment Maps”, SIGGRAPH, pp. 251-258, August 1997. [9]Andreas Gustafsson ,“Interactive Image Warping”, Information of Technology Helsinky University of Technology Master''s Thesis, May 31, 1993. [10]R. Raskar, G. Welch and H. Fuchs, “Seamless projection overlaps using image warping and intensity blending”, Fourth International Conference on Virtual Systems and Multimedia, Gifu, Japan, 1998. [11]T. Takahashi, N. Numa, T. Aoki, S. Kondo, “A geometric correction method for projected images using SIFT feature points”, Proceedings of the 5th ACM/IEEE International Workshop on Projector camera systems, article no. 4, 2008. [12]L. McMillan, “An image-based approach to three-dimensional computer graphics”, PHD's Thesis, the University of North Carolina at Chapel, 1997. [13]Y.T. Tang, and C.Y. Suen, “Image transformation approach to nonlinear shape restoration”, IEEE Transactions on Systems, Man and Cybernetics, vol. 23, pp. 155-171, 1993. [14]C.A. Glasbey and K.V. Mardia, “A review of image warping methods”, Journal of Applied Statistics, vol. 25, pp. 155-171, April 1998. [15]David A. Forsyth, Jean Ponce, “Computer Vision A modern Approach”, Prentice Hall, 2003. [16]Rafael C. Gonzalez, Richard E, Woods, Steven L. Eddins, “Digital Image Processing Using Matlab, 1st Edition”, Prentice Hall, 2004.
摘要: 
由於近年來投影機的大量生產連帶促使其價格變得更為平易近人,加上投影機有著與同等價位的電視難以匹敵的大尺寸畫面,再配合投影機技術不斷演化後其無論是在解析度或是色彩飽合度上都已達到相當水準,使得投影機的應用已經開始從原本的商用展場、大型簡報室等等逐漸普及到一般教室甚至是家庭劇院中。這些現象都在在顯示投影機已從原先的專業產品蛻變成一般消費型電子商品,因此如何更進一步提升投影機的應用範圍,也成為近年來最重要的課題之一。
本文第一章首先探討現行的多投影機影像幾何修正系統,其大部分都是以電腦後製或是安裝高階顯示卡的方式完成,不僅成本十分昂貴,對於電腦的依附程度也是相當地高。為改善這樣的狀況,本研究提出以易參數化之橢圓柱面做為投影面模型,並以低成本硬體實現多投影機影像幾何修正系統。
在使用多投影機拼接投影時,往往會出現未密合之間隙或是重疊的亮帶。第二章引入影像柔邊技術以消除這類情況,此技術透過漸層各投影機之重疊區亮度,使其拼接後的影像看來平順連續。而為了後續發展的影像幾何修正演算法,投影機的內部構造與光學特性也將在本章中討論。
在了解影像柔邊技術與投影機特性後,第三章首先探討投影在非平面時投影畫面變形的原理,再透過投影機特性建立橢圓柱面投影模型,推導出正投影之影像幾何修正演算法。接著更進一步修改模型使其符合實際使用上需求,並以此推導出更具一般性的側投影之影像幾何修正演算法。而為減少硬體執行上的負擔,再將演算法進行必要的化簡,經觀察化簡後之計算量,提出以查表方式更進一步降低計算亮。最後概略介紹本系統之運作流程與各模組的功能。
為更進一步實現多投影機影像幾何修正系統,在第四章將進行模擬分析與數個實際投影實驗。影像柔邊實驗主要為驗證影像柔邊技術理論與實際投影是否相符;Fixed-Point分析則可做為建表精準度之參考;為轉換實際物理量與數位影像單位而進行影像單位轉換實驗;單投影機投影橢圓柱面實驗主要為驗證影像幾何修正演算法的正確性;最後將以雙投影機投影橢圓柱面實驗驗證多投影機影像幾何修正系統。第五章針對各項實驗結果與演算法缺失,提出可能的改進方式。
本研究提出以低成本硬體實現多投影機幾何修正系統,不僅降低對電腦的依附程度,更進一步降低投影環境對投影機的限制。預計本研究的成果將為投影機的應用帶來更寬廣的視野。

Friendly price, large-screen, and high quality of resolution and colorfulness make projectors appear not only in exhibitions and meeting rooms but also in classrooms and home theaters. This shows that projectors have become commercial manufactures from professional products. Therefore, how to improve the application of projectors turns into one of the most important topics these years.
First, the chapter one of this paper discusses the available systems of multi-projectors-geometric-correction, but most of them use either computer-retouching or high performance graphic processors which are highly dependent on computers and very expansive. To improve the situation this paper provide a solution which models curved projecting surface on the lateral surface of cylindroid and implements the system of multi-projectors-geometric-correction with low-cost hardware.
Either a gap between the images or a double bright seam usually appears when sewing multiple projection images. “Edge Blending” is introduced in chapter two to remove the double bright seam. This technique decreases the pixel in overlap region of each projector to make the projection smooth. In addition, the structure and optics properties of projectors are mentioned in this chapter, too.
The distortion of projections on non-plat surface is first described in chapter three. Through the properties of projectors, we construct a projection model which takes the lateral surface of cylindroid as projecting surface and develop a geometric correction algorithm. Further, we modify the model to make it more practical and develop an algorithm with more generality. To reduce the operation, the algorithm is simplified, but the operation is still too complex to implement, therefore the look-up-table is proposed. We introduce our system in the last of this chapter.
In chapter four, the results of simulations and practical projecting experiments are demonstrated. The experimental results in chapter four and the drawback of the algorithm are discussed in chapter five. The conclusion and future work are also proposed in this chapter, too.
This paper provides a solution which implements the system of multi-projectors-geometric-correction. This system reduces not only the dependence on computers but also the limitation from the projecting surrounding. We expect that the results of this study will provide a wide application for projectors.
URI: http://hdl.handle.net/11455/8755
其他識別: U0005-0208201016184100
Appears in Collections:電機工程學系所

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