非平面投影畫面變形校正之研究

A Calibration of Deformed Projection on Non-planar Surfaces

余俊傑(Chun-Chieh Yu)

指導教授 ： 曾百由

國立臺北科技大學/機電學院/機電整合研究所/碩士(2011年)

https://doi.org/10.6841/NTUT.2011.00440

摘要

本論文利用Bezier,B-Spline演算法改善投影機投影在非平面畫面變形修正的問題。當投影機投影俯仰角度過大時，投影在平面會有變形的梯形畫面，此時觀賞者所欣賞的影像畫面是有變形問題。同樣地，在全景環幕電影播放時，投影機投影至環狀圓柱面上，觀賞者位於環狀形中央區，所看到的影像畫面也有同樣問題。環幕電影是一種相當特殊的電影，製作上是由多部攝影機同步全景角拍攝影像，事先須已知播放場景大小、投影機投影焦距長才能作影像彎曲合成為全景影像，接著由多部投影機同步不同角度播放在環狀圓柱面上，進行投影機調整接合畫面，相鄰的畫面彼此之間有重疊與接合的問題。因此我們希望影像輸出的畫面能有所調整以滿足投影在任意曲面上的需求，本研究利用Bezier或B-Spline演算法，重新計算曲面形狀，再將影像重新修正投影至曲面上。在重新計算影像調整時，如有畫素短少情形，可以增加線性插值密度或使用插補法方式作修正。

關鍵字

Bezier ； B-Spline ； 相關係數 ； 圖樣比對 ； 非平面投影

並列摘要

This thesis aims to improve the distorted image correction by making use of Bezier curve or B-Spline curve compensating calculation especially for distortion of image projected onto a non-planar surface. When an image projection is done by the projector at an excessive pitch angle, the projected image on the projection surface turns into trapezoidal non-rectangular shape; the image frame seen by the audience has a distortion problem. Likewise, the same distortion problem happens to the image frame viewed by the viewer sitting in the central area of the circular movie theater while watching movie images projected onto the surface of the circular column during a panorama circular-screen movie show.Circular-screen movie film as a unique category is technically demanding in production requiring multiple cameras to shoot panorama images synchronously to the prior known data including the display screen size and the projector’s projection focal length in order to undergo the image warping process for synthesizing the panorama image, and next to have the panorama images projected on to the circular column screen surface synchronously by multiple projectors for undergoing the process of stitching the image by adjusting the projectors; and here stitching the neighboring images together requires techniques to address the overlapping and perfectly matching issues.Hence, this thesis seeks possibility of making certain adjustment in the frame of the image output to satisfy the demands of projecting images on curved surface, and thus this thesis finds the solution of making use of Bezier or B-Spline curve compensating calculations to firstly recalculating the shape on the curved surface and then projecting the images onto the curved projection surface after having gone through the correction process. Furthermore, a correction for addressing the pixel shortage encountered during recalculation of the curved surface can be done by either increasing the density of linear interpolation or making use of data imputation.

並列關鍵字

Bezier ； B-Spline ； Correlation Coefficient ； Template Matching ； Non-planar Projection

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