Development of Automatic Followspot System with Robust and Real-time Tracking Algorithm
Date Issued
2007
Date
2007
Author(s)
Wu, Chun-Han
DOI
zh-TW
Abstract
An automated followspot tracking system with a robust and real-time tracking algorithm was developed. The proposed image tracking algorithm has two advantages: robustness and real-time processing. Our approach is divided into three parts: image acquisition, tracking, and spot following. In the beginning, image sequences are captured by a machine vision system. Operators select the upper body and the lower body of an actor to be tracked. The actor’s movement information is extracted through a series of image processings and then sent to the tracking part. There are two most important methods in our tracking algorithm. The first method is the interlocked dual-feature mean shift which considers both color and spatial difference features. We adopt this method because failure occurs when we use the mean shift approach with only one single feature, which considers only color feature, if the actor passes by another actor in the same color of his half body. However, the interlocked dual-feature mean shift could overcome the shortcoming. The second method is the updated Kalman filters which estimate system noise and measurement noise, and then update the corresponding parameters. The estimated states consist of position, velocity and acceleration of the actor. The estimated position is sent not only to the followspot controller for lighting but also back to the interlocked dual-feature mean shift for updating the centers of searching regions in the next sampling time. Also, the estimated velocity is employed to adjust dynamically the searching region. Results show that the approach with the updated Kalman filter is more robust than the non-updated one because the rate of successful tracking is highly promoted. The maximum tracking velocity is up to 111.3 pixel/sec, which is sufficient for tracking characters on stage. The algorithm improves the disadvantages of current followspot system, such as high price and inconvenience. Consequently, the developed system is more economical, manpower-saving, and easy to setup and operate.
Subjects
即時影像追蹤
機器視覺
均值移動演算法
卡爾曼濾波器
模型
估測
追蹤燈
自動化
real-time video tracking
machine vision
mean shift
Kalman filter
model
estimation
followspot
automation
Type
thesis
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