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  • 學位論文

基於線上學習之視覺追蹤

An online learning based vision tracking

指導教授 : 顏淑惠

摘要


即時的追蹤在電腦視覺中一直以來都是很重要的研究題目,本文裡我們提出了一個改善 Grabner和 Bischof於2006年所發表的On-line Boosting的追蹤方法。我們僅使用了簡單的Haar-like特徵來描述目標,並做篩選將表現比較好的特徵加入feature pool,而之後的強分類器訓練只需考慮這些特徵以有效的減少計算量。為了能適應前景/背景的變化,本文採取sample pool的方法進行分類器的即時更新,所賴以更新的訓練樣本則依照計算出的信任值,信任值高時更新sample pool的正樣本反之則更新負樣本;同時每隔一段時間,feature pool中的弱分類器的門檻值也會重新設定。我們並且使用background subtraction與Kalman filter來避免相似背景與雜訊的影響,並進行目標被遮蔽之後的路徑預測。實驗結果顯示,我們所提出的方法比原先的方法,能保有穩定且令人滿意的結果。

並列摘要


On-line tracking is main topic in computer vision. In this paper, we proposed a method based on On-line Boosting proposed by Grabner and Bischof. We only use Haar –like feature to describe target. We add good features into feature pool and then when training the strong classifier, we only use those features to decrease the computation. To adapt the changing of foreground and background we use sample pool to online update classifiers. When the confidence values are high, we update the positive samples in sample pool and vice versa. Meanwhile, we reset the threshold of weak classifiers every ten frames. We use background subtraction to avoid the effect of similar background and noise and Kalman filter to predict the object trajectory when it was occluded. From the experimental results, our method is more stable and accurate.

參考文獻


[1] M. Dikmen, D. Hoiem and T. Huang, "A Data Driven Method for Feature Transformation," CVPR '12 Proceedings of the 2012 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), pp. 3314-3321, 16 06 2012.
[2] J. Kwon and K. Mu, "A Unified Framework for Event Summarization and Rare Event Detection," IEEE Conference on Computer Vision and Pattern Recognition(CVPR), p. 1266 – 1273, 16-21 6 2012.
[4] K. Fukunaga and L. Hostetler, "The estimation of the gradient of a density function, with applications in pattern recognition," Information Theory, IEEE Transactions on (Volume:21 , Issue: 1 ), pp. 32 - 40, 1 1975.
[6] B. Yang and R. Nevatia, "Online Learned Discriminative Part-Based Appearance Models for Multi-human Tracking," 12th European Conference on Computer Vision, pp. 484-498, 7-13 10 2012.
[7] S. Avidan, "Ensemble Tracking," IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR'05)- Volume 2 , pp. 494-501, 2 2005.

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