未校正立體像機之自動化影像對正技術

Automated Image Rectification of Uncalibrated Stereo Cameras

張鈺偉(Yu-Wei Zhang)

指導教授 ： 林巍聳

國立臺灣大學/電機資訊學院/電機工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.02121

摘要

用立體機器視覺擔任行動機器人的運動導向時，需由不同視角的影像求取立體的空間資訊，而影像對正可以把左右影像轉換成對正的影像，使每一對水平掃描線都與共極線吻合，如此一來，在對正過的左右影像中搜尋對應點時，只需在相同水平的掃描線中搜尋即可，搜尋對應點的工作因而變成比較有效率的一維演算。要達成影像對正，至少必須知道左右影像上的八對對應點，才能求解對正的轉換矩陣，前人的研究是用人工挑選出這八對對應點，本研究則發展出一套自動化的彩色樣本對應法來找到足夠的對應點，彩色樣本用顏色、亮度和形狀來區別，對應點即取為所估測對應的彩色樣本的形心，這套自動化的對正方法已經用兩組立體攝影機的實驗結果證實為有效而且精準。

關鍵字

立體機器視覺 ； 對應點 ； 影像對正 ； 共極線 ； 立體攝影機

並列摘要

Using machine stereovision for the guidance of mobile robot needs to extract the 3D information from images captured at different viewpoints. The image rectification can transform the associated images into a format, which have the horizontal image lines coinciding with the epipolar lines. Thus the stereo matching can search in the rectified images simply along epipolar lines, which is basically one-dimensional. Rectification of uncalibrated images needs to know no less than eight pairs of corresponding points to estimate the homographies. Conventional approach presented in literature provides the corresponding points by manual selections. This research develops an automated method of matching color patterns to find the required number of corresponding points. A pair of corresponding points is estimated as the centroid of a pair of corresponding color patterns. The patterns are discriminated by according to their color, intensity and shape. This automated approach is shown to be efficient and accurate. Experimental results from two sets of binocular camera are shown.

並列關鍵字

epipolar lines ； stereovision ； rectification ； homographies ； uncalibrated

參考文獻

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