基於流場相似度進行影片運鏡模擬

Flow Field Similes

蘇品靜(Pin-Ching Su)

指導教授 ： 陳煥宗

國立清華大學/電機資訊學院/資訊工程學系/碩士(2013年)

摘要

本論文提出了一個基於流場相似度將專業影片的運鏡模式和拍攝風格傳遞至非專業影片的想法。給定一段非專業的影片及一段參考的流場，我們的目標是計算出一系列的平面轉換並套用至該非專業影片，使其修正後的流場與參考流場相似。此參考的流場可能來自於一段真正的影片或者是合成的結果。我們制定了一個在稀疏對應點上的非線性最佳化問題，透過讓輸出影片流場和參考流場的差異達到最小的方式為影片的每一個影格找到最適合的轉換。我們的實驗結果展示了透過讓輸出影片的流場與參考的流場相似，能夠創造出不同類型的攝影機運鏡方式與拍攝風格，從簡單的影片穩定效果到更複雜的特效，如平滑的縮放、抗模糊快速移動、同時旋轉變焦、跟蹤拍攝和推軌變焦。

關鍵字

影片編輯 ； 流場 ； 影像變形

並列摘要

This paper introduces the idea of flow field similes for transferring better camera movements and shooting styles from a reference flow field to carelessly shot videos. Given an input video and a reference flow field, we aim to compute a series of homography transformations to warp the input video, so that the flow of the output video will closely resemble the reference flow. The reference flow field may be derived from a real video or synthetically generated. We formulate a nonlinear optimization problem over sparse feature correspondences to find the required transformation for each video frame, through minimizing the difference between the intended reference flow field and the flow field of the output video frame. We show that, by enforcing the flow field of output video to resemble the reference flow field, we are able to create different types of camera movements and shooting styles, from the simplest effect of video stabilization to more complex ones like smooth zooming, anti-blur fast panning, zooming while rotating, tracking shot, and dolly zoom.

並列關鍵字

video editing ； optical flow ； image warping

參考文獻

[1] Simon Baker, Daniel Scharstein, J. P. Lewis, Stefan Roth, Michael J. Black, and Richard Szeliski. A database and evaluation methodology for optical flow. In ICCV, pages 1-8, 2007.

[2] Michael J. Black and P. Anandan. The robust estimation of multiple motions: Parametric and piecewise-smooth flow fields. Computer Vision and Image Understanding, 63(1):75-104, 1996.

[3] Thomas Brox, Andres Bruhn, Nils Papenberg, and Joachim Weickert. High accuracy optical flow estimation based on a theory for warping. In ECCV (4), pages 25-36, 2004.

[4] Thomas Brox and Jitendra Malik. Large displacement optical flow: Descriptor matching in variational motion estimation. IEEE Trans. Pattern Anal. Mach. Intell., 33(3):500-513, 2011.

[5] Andres Bruhn, Joachim Weickert, and Christoph Schnorr. Lucas/kanade meets horn/schunck: Combining local and global optic flow methods. International Journal of Computer Vision, 61(3):211-231, 2005.