- 學位論文
立體匹配演算法使用階層式過度分割與可信度傳遞
Stereo Matching Algorithm using Hierarchical Over-segmentation and Belief Propagation
摘要
在本篇論文中，我們提出了一個從校正好的一組影像得到視差圖的新演算法。我們首先使用影像過度分割來建立以內容為基礎的階層式馬可夫隨機場。這種影像表示方式包含了兩個利於做視覺應用的優點。第一個是階層式馬可夫隨機場的建立，而另一個是正規的圖形結構。前者已經被廣泛地應用於電腦視覺的問題來改進最佳化馬可夫隨機場的效率。後者可以簡化最佳化馬可夫隨機場技術其訊息的傳遞和硬體的實作。在建立完以內容為基礎的階層式馬可夫隨機場後，我們使用階層式可信度傳遞於對稱的立體匹配與遮蔽處理在提出的圖形模型上。最後，引進一個精煉視差圖的方法(例如平面擬合或雙向濾波器)來減少因遮蔽、無紋理區域或是影像上雜訊等等導致視差的錯誤估計。我們的實驗結果展現出我們可以有效率地獲得媲美大部分全局立體匹配演算法的準確度之視差圖。對於真實的影像序列，我們可以先使用強健的自身影像校正前處理來準確地估計出每張影格的深度資訊。
並列摘要
In this thesis, we present a novel algorithm to infer disparity map from given a pair of rectified images. We first employ image over-segmentation to construct a Content-based Hierarchical Markov Random Field (CHMRF). This image representation contains two advantages for vision applications. One is the hierarchical MRF construction, and the other is the regular graph structure. The former has been widely applied to computer vision problems to improve the efficiency in MRF optimization. The latter can simplify the message passing and hardware implementation of MRF optimization techniques. After the construction of CHMRF, we perform symmetric stereo matching and occlusion handing using Hierarchical Belief Propagation (HBP) based on the proposed graphical model. Finally, a refinement process for the disparity map is introduced (e.g. plane fitting or bilateral filtering) to reduce the disparity errors caused by occlusion, textureless region or image noise, etc. Our experimental results show that we can efficiently obtain disparity maps of comparable accuracy when compared to most global stereo algorithms. For real stereo video sequences, we are able to accurately estimate the depth information for each frame with the pre-processing of robust self image rectification.