使用可動式投影機之互動式多重解析度曲面顯示裝置之校正方法

曲面大型觸控螢幕很適合用在展示、教學上,比起平面螢幕,曲面螢幕可以同時讓更多人共同操作,並且在空間設計上也更加靈活而生動。為了在投影出大畫面的同時提高使用者關注的小區域內的解析度以呈現內容細節,我們可以在投影全畫面的廣角投影機之外,增加設置數台高解析度而投影面積較小的投影機,並在高解析度投影機前裝設一面反射鏡,以一台可精確控制兩軸旋轉角度的運動控制器旋轉鏡子到指定角度,使得投影機的光線經過鏡子反射後可以投影到螢幕的任意位置。要計算出經過反射之後能將內容正確投影在曲面螢幕上的投影畫面是非常具挑戰性的。現有的方法只將可動投影機應用在平面投影上, 在反射鏡旋轉到某些取樣角度處進行局部的校正,並使用內插法計算非取樣角度處的投影模型。若要將這種方法應用在曲面螢幕上,必須將每個取樣角度間的距離縮小到使該區間內的曲面變化逼近平面,大幅提高了所需取樣角度的數量,使得校正過程過分耗時耗力。本篇論文提出一種以重建單純物理模型的方式,在軟體中模擬投影機光線在實際空間中的路徑而得到能正確投影的畫面,並且設計一套自動化測量物理模型中參數的方法,以建造出快速校正的投影系統。完成之程式架構能抓取視窗內容,並套用校正參數使其能正確的投影到曲面螢幕上,同時將紅外線攝影機拍攝觸控曲面的影像進行幾何矯正並抓取使用者觸控的位置傳遞給外部程式處理互動內容,讓互動內容設計人員可以直接使用此架構處理投影觸控系統的種種細節,以專注在其互動內容之開發。關鍵字:多重解析度 (Multi-Resolution)、多點觸控 (Multi-Touch)、可動式投影機 (Steerable Projector)、曲面顯示裝置 (Curved Display Sys- tem)、幾何校正 (Geometric Calibration)、物理模型 (Physics Model)

關鍵字

多重解析度；多點觸控；可動式投影機；曲面顯示裝置；幾何校正；物理模型

並列摘要

Curved multi-touch screen is very useful in the purpose of exhibition and demonstration. Compared with planar screen, a curved interactive screen al- lows more users to interact simultaneously in a limited space, and makes the interior design of the exhibition room more flexible. Using a single projec- tor for the whole screen area provides a coarse scene with very low resolu- tion. In order to express more content details, we can add a high-resolution projector along with the large-area projector to project in a smaller area of user's attention. A mirror controlled by pan-tilt-unit is installed in front of the high-resolution projector. By rotating pan and tilt angles, the high-resolution projection area can be moved to any location on the screen. It is very challenging to calculate the projecting image that display the content correctly on a curved screen after PTU-controlled mirror reflection. Existing calibration method use the steerable projector on planar screen only. They sample some pan-tilt angles and calculate the homography between screen and projector at that angle, just like in calibration of fixed projector. When the projector rotate to un-sampled angle, they interpolate the homogra- phy from nearby sample angles. To deal with a curved screen by this method, we have to make the sample angles very close enough that the small piece of curve between them approaches planar. This significantly increases the required number of sample angles, and let the calibration procedure too time- consuming. In this paper, we propose a new method for calibration by reconstructing the physics model of the devices, and simulate the light path of projector in 3D rendering software to get a projecting image which can project the content on the curved screen correctly. For estimating the parameters in the model, we propose a method that can do the whole procedure fast and automatically. With this method we can build a projecting system with very fast and effortless calibration. To utilize the calibration result, we implement a program that can capture the content of other window, and warp the image by the calibrated parameters to project it correctly on the curved screen. This program also warp the IR- camera image and detect finger touches in curved screen's 2D coordinate to send back to the interactive content application. For an interactive content designer, our program can handle all the details about the interactive display system, thus enables he or she to focus on the content development. Key words: Multi-Resolution, Multi-Touch, Steerable Projector, Curved Display System, Geometric Calibration, Physics Model

並列關鍵字

Multi-Resolution ； Multi-Touch ； Steerable Projector ； Curved Display System ； Geometric Calibration ； Physics Model

參考文獻

[2] Yan-Yu Chang. i-m-tube: Interactive multi-resolution tubular display. Master's thesis, National Taiwan University, July 2009.

[3] Mark Ashdown and Yoichi Sato. Steerable projector calibration. In Computer Vision

[4] Zhengyou Zhang. Flexible camera calibration by viewing a plane from unknown orientations. In Computer Vision, 1999. The Proceedings of the Seventh IEEE

[1] Jin-Yao Lin, Yen-Yu Chen, Ju-Chun Ko, HuiShan Kao, Wei-Han Chen, Tsun-Hung Tsai, Su-Chu Hsu, and Yi-Ping Hung. im-tube: an interactive multi-resolution tubular display. In Proceedings of the 17th ACM international conference on Multimedia,

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pages 253--260. ACM, 2009.

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使用可動式投影機之互動式多重解析度曲面顯示裝置之校正方法

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