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Real Time Appearance Based Hand Tracking. The 19th International Conference on Pattern Recognition (ICPR) December 7-11, 2008, Tampa Convention Center, Tampa, FL, USA 報告者:彭成瑋 日期: 2009/12/29 指導教授:陳立祥 教授 實驗室:網際網路多媒體應用實驗室. Outline. Introduction Tracking method Experiments Conclusion Q&A.
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Real Time Appearance Based Hand Tracking The 19th International Conference on Pattern Recognition (ICPR) December 7-11, 2008, Tampa Convention Center, Tampa, FL, USA 報告者:彭成瑋 日期:2009/12/29 指導教授:陳立祥 教授 實驗室:網際網路多媒體應用實驗室
Outline • Introduction • Tracking method • Experiments • Conclusion • Q&A
Introduction • Hand tracking is an important problem in the field of human-computer interaction. • Application:sign language recognition or controlling computer games. • Model-based(3D model) and Appearance-based (Image features)
Introduction( Cont. ) • the hand presents a motion of 27 degrees of freedom (DOF), 21 for the joint angles and 6 for orientation and location[11, 10]. • Substantial problems:out-of-plane rotations scale changes, self-occlusions or segmentation accuracy. • Real-time tracking performance • Maximally Stable Extremal Region (MSER) tracking algorithm.
Tracking method • Novel tracking method • Multivariate Gaussians with the Kullback-Leibler distance
Color likelihood • calculate a probability value p(O|xi) for every pixel in the current frame • object-to-be-tracked (hand) O • Kullback-Leibler distance instead of the Bhattacharyya distance • The integral image for Bhattacharyya distance calculation
Color likelihood ( Cont. ) • Mahalanobis Distance • Bhattacharyya Distance
Color likelihood ( Cont. ) • color likelihood value -- p(O|xi) • every pixel –xi • r × c window • color distribution of the hand O in the frame t−1 -- Gaussian • 3×1 mean vector –μO • 3×3 covariance matrix -- Gaussian • multivariate Gaussian --
Maximally Stable Extremal Region (MSER) tracking • (a) Input Image (b) Image histogram (c) MSER result
Modified MSER tracking • (a) Color likelihood (b) MSER detection result
Experiments • 25 frames per second on a 320 × 240 video sequences
Experiments(Cont.) • A simple gesture recognition allows to use the tracker for controlling the mouse pointer and activating mouse-clicks.
Conclusion • Novel real time method for tracking hands through image sequences • Efficiently calculated color similarity maps
Q&A • Q:為什麼選擇使用Appearance-based 來實作. • A:為了符合即時運算之效能考量,因為Model-based使用3D model來辨識,需花費較多運算量。